{"T9": {"n": 9, "t": "Grand All-Subject", "d": "Oct 8 2026", "q": [{"n": 1, "s": "A 28-year-old pregnant woman undergoes a 75 g oral glucose tolerance test at 26 weeks. Her results are: fasting 95 mg/dL, 1-hour 175 mg/dL, 2-hour 150 mg/dL. What is the diagnosis and management implication?", "o": [["A", "Normal glucose tolerance — no follow-up"], ["B", "Pre-existing type 2 diabetes"], ["C", "Impaired glucose tolerance only — observe"], ["D", "Gestational diabetes (OGTT thresholds met) — diet then insulin if needed"]], "c": ["D)", "Gestational diabetes (OGTT thresholds met) — diet then insulin if needed"], "co": "Gestational diabetes — OGTT thresholds (fasting ≥92, 1h ≥180, 2h ≥153)", "ct": "Analysis/synthesis", "w": "Gestational diabetes is diagnosed by a 75 g OGTT at 24-28 weeks using IADPSG thresholds: fasting ≥92 mg/dL, 1-hour ≥180, or 2-hour ≥153 — meeting ANY one suffices. Management begins with diet/exercise; insulin (or metformin) is added if glycemic targets are not met. Women with GDM need postpartum glucose testing (future T2DM risk).", "d": "Pregnancy OGTT meeting ANY threshold (92/180/153) = GDM → diet, insulin if targets unmet", "t": "Population-specific — GDM OGTT thresholds (92/180/153), screen 24-28w", "f": "GDM: OGTT at 24-28w; any of fasting ≥92/1h ≥180/2h ≥153 = GDM → diet then insulin", "r": "Gestational diabetes: 75g OGTT (fasting ≥92, 1h ≥180, 2h ≥153); diet ± insulin; postpartum test", "x": [["A) Normal glucose tolerance — no follow-up", "Meeting a threshold diagnoses GDM; this is not normal tolerance."], ["B) Pre-existing type 2 diabetes", "Pre-existing diabetes is diagnosed by elevated glucose BEFORE pregnancy, not a GDM OGTT."], ["C) Impaired glucose tolerance only — observe", "These values meet diagnostic thresholds, not just 'impaired' — treatment is indicated."]]}, {"n": 2, "s": "A 55-year-old man develops hyponatremia 4 days after a subarachnoid haemorrhage. He is clinically volume-depleted with low urine sodium. Which diagnosis is most likely?", "o": [["A", "SIADH"], ["B", "Hypothyroidism"], ["C", "Nephrogenic diabetes insipidus"], ["D", "Cerebral salt wasting"]], "c": ["D)", "Cerebral salt wasting"], "co": "Cerebral salt wasting — SAH + hyponatremia + volume depletion", "ct": "Analysis/synthesis", "w": "Cerebral salt wasting follows CNS injury (subarachnoid haemorrhage) and causes natriuresis leading to volume depletion and hyponatremia. The key discriminator from SIADH is the volume status: CSW is hypovolemic, SIADH is euvolemic. CSW is treated with volume repletion (fluids + salt), whereas SIADH is treated with fluid restriction.", "d": "SAH + hyponatremia + VOLUME DEPLETION = cerebral salt wasting (vs SIADH which is euvolemic)", "t": "Opposite — CSW (hypovolemic) vs SIADH (euvolemic)", "f": "CNS injury + hyponatremia + volume depletion = cerebral salt wasting → saline", "r": "CSW = natriuresis after CNS injury with volume depletion; SIADH is euvolemic", "x": [["A) SIADH", "SIADH is euvolemic with concentrated urine, not volume-depleted."], ["B) Hypothyroidism", "Hypothyroidism causes mild hyponatremia but not acute after SAH."], ["C) Nephrogenic diabetes insipidus", "Diabetes insipidus causes hypernatremia, not hyponatremia."]]}, {"n": 3, "s": "A 48-year-old man with heavy alcohol use presents with jaundice, tender hepatomegaly, and a Maddrey discriminant function of 40. He has no gastrointestinal bleeding or sepsis. What is the most appropriate treatment?", "o": [["A", "Pentoxifylline"], ["B", "Observation alone"], ["C", "Immediate liver transplant"], ["D", "Prednisolone"]], "c": ["D)", "Prednisolone"], "co": "Alcoholic hepatitis — Maddrey DF >32 → corticosteroids", "ct": "Analysis/synthesis", "w": "A Maddrey discriminant function >32 defines severe alcoholic hepatitis, for which prednisolone reduces short-term mortality — provided there is no active infection, GI bleeding, or renal failure. Pentoxifylline is no longer recommended; transplant requires abstinence.", "d": "Alcoholic hepatitis + Maddrey DF >32 (severe) → prednisolone (reduces mortality)", "t": "Unit/Number — Maddrey >32 threshold for steroids", "f": "Alcoholic hepatitis + Maddrey >32 = prednisolone (after excluding infection/bleed)", "r": "Severe alcoholic hepatitis (Maddrey >32) → prednisolone; screen for infection/bleed first", "x": [["A) Pentoxifylline", "Pentoxifylline is not recommended; it does not reduce mortality."], ["B) Observation alone", "Severe alcoholic hepatitis (DF >32) warrants treatment, not observation."], ["C) Immediate liver transplant", "Transplant requires a period of abstinence and is not the immediate step."]]}, {"n": 4, "s": "A 52-year-old man presents with migratory arthralgia, chronic diarrhoea, and weight loss. Small-bowel biopsy shows PAS-positive foamy macrophages in the lamina propria. What is the most appropriate initial treatment?", "o": [["A", "Metronidazole for 7 days"], ["B", "Oral glucocorticoids"], ["C", "Gluten-free diet"], ["D", "Ceftriaxone followed by trimethoprim-sulfamethoxazole"]], "c": ["D)", "Ceftriaxone followed by trimethoprim-sulfamethoxazole"], "co": "Whipple disease — Tropheryma whipplei, PAS+ macrophages → prolonged antibiotics", "ct": "Analysis/synthesis", "w": "Whipple disease is caused by Tropheryma whipplei, presenting with arthralgia, diarrhoea, and weight loss; PAS-positive foamy macrophages are diagnostic. Treatment is prolonged — IV ceftriaxone initially, then oral trimethoprim-sulfamethoxazole for about a year.", "d": "Arthralgia + diarrhoea + PAS+ macrophages = Whipple disease → prolonged antibiotics (ceftriaxone then TMP-SMX)", "t": "Treatment misdirection — short antibiotic course vs prolonged therapy", "f": "Arthralgia + diarrhoea + PAS+ macrophages = Whipple → prolonged antibiotics (1 year)", "r": "Whipple = arthralgia + diarrhoea + PAS+ macrophages → prolonged antibiotics", "x": [["A) Metronidazole for 7 days", "A 7-day metronidazole course is inadequate — Whipple requires prolonged therapy to prevent relapse."], ["B) Oral glucocorticoids", "Glucocorticoids do not treat the infection."], ["C) Gluten-free diet", "A gluten-free diet treats coeliac disease, not Whipple disease."]]}, {"n": 5, "s": "A 20-year-old man with newly diagnosed Burkitt lymphoma develops oliguria 24 hours after starting chemotherapy. Labs show potassium 6.8 mmol/L, phosphate 7.5 mg/dL, uric acid 14 mg/dL, and calcium 6.0 mg/dL. What is the most likely diagnosis?", "o": [["A", "Rhabdomyolysis"], ["B", "Contrast nephropathy"], ["C", "Acute interstitial nephritis"], ["D", "Tumour lysis syndrome"]], "c": ["D)", "Tumour lysis syndrome"], "co": "Tumour lysis syndrome — post-chemotherapy AKI with hyperK + hyperPO4 + hyperuricemia + hypocalcemia", "ct": "Analysis/synthesis", "w": "Tumour lysis syndrome follows chemotherapy of rapidly proliferating tumours (Burkitt, ALL), releasing intracellular contents: hyperkalaemia, hyperphosphataemia, hyperuricaemia, and secondary hypocalcaemia, causing AKI. Prevention is hydration, allopurinol/rasburicase; treatment of hyperkalaemia is urgent.", "d": "Chemotherapy + oliguria + hyperK + hyperPO4 + hyperuricemia + hypocalcemia = tumour lysis syndrome", "t": "Clinical Mimic — TLS vs rhabdomyolysis (chemotherapy context + uric acid)", "f": "Post-chemo AKI + hyperK + hyperPO4 + hyperuricemia = tumour lysis syndrome", "r": "TLS = post-chemo AKI with hyperK, hyperPO4, hyperuricemia, hypocalcemia → hydration + rasburicase", "x": [["A) Rhabdomyolysis", "Rhabdomyolysis has muscle injury and myoglobinuria, not the chemotherapy context."], ["B) Contrast nephropathy", "Contrast nephropathy follows contrast exposure, not chemotherapy."], ["C) Acute interstitial nephritis", "AIN is drug-hypersensitivity with eosinophilia, not this metabolic pattern."]]}, {"n": 6, "s": "A diabetic man has a painless plantar ulcer with a warm foot and easily palpable pedal pulses. A second patient has a painful, cool foot with absent pulses and rest pain. How do these ulcers differ?", "o": [["A", "Both are purely infectious"], ["B", "Both are venous"], ["C", "First is arterial, second is neuropathic"], ["D", "First is neuropathic (sensory loss, good perfusion); second is ischaemic (poor perfusion)"]], "c": ["D)", "First is neuropathic (sensory loss, good perfusion); second is ischaemic (poor perfusion)"], "co": "Diabetic foot ulcer — neuropathic (warm, pulses) vs ischaemic (cool, absent pulses)", "ct": "Interpretation", "w": "Diabetic foot ulcers are classified by aetiology: neuropathic ulcers occur in insensate feet (painless, warm, with palpable pulses, often plantar), while ischaemic ulcers stem from peripheral arterial disease (painful, cool, absent pulses, rest pain, often at pressure points/tips). Mixed ulcers are common. Management differs — neuropathy needs offloading; ischaemia needs revascularisation. (Wagner grade assesses depth/infection separately.)", "d": "Painless + warm + palpable pulses = neuropathic ulcer; painful + cool + absent pulses = ischaemic", "t": "Opposite — neuropathic (warm, pulses present) vs ischaemic (cold, pulses absent)", "f": "Painless warm foot with pulses = neuropathic ulcer; painful cold foot no pulses = ischaemic", "r": "Neuropathic foot ulcer: painless, warm, palpable pulses; ischaemic: painful, cool, absent pulses (PAD)", "x": [["A) Both are purely infectious", "Infection is a complication, not the primary classification of these ulcers."], ["B) Both are venous", "Venous ulcers occur in the gaiter area with oedema/varicosities, not this picture."], ["C) First is arterial, second is neuropathic", "The attributions are reversed — the painless warm one is neuropathic, not arterial."]]}, {"n": 7, "s": "A patient on furosemide with vomiting and metabolic alkalosis has serum potassium of 2.8 mmol/L. Which combination of mechanisms explains the hypokalemia?", "o": [["A", "Only dietary deficiency"], ["B", "Only transcellular shift from insulin"], ["C", "Magnesium excess"], ["D", "Renal K loss (diuretic) + GI loss (vomiting) + shift into cells (alkalosis)"]], "c": ["D)", "Renal K loss (diuretic) + GI loss (vomiting) + shift into cells (alkalosis)"], "co": "Hypokalemia — multifactorial (renal + GI loss + alkalosis shift)", "ct": "Interpretation", "w": "Hypokalemia here arises from three mechanisms: loop diuretic causes renal potassium wasting, vomiting causes gastric loss, and metabolic alkalosis drives extracellular K into cells. Recognizing the multifactorial cause guides both replacement and correction of the underlying driver (stop diuretic, treat vomiting/alkalosis).", "d": "Diuretic + vomiting + alkalosis = combined renal/GI K loss plus intracellular shift", "t": "Treatment misdirection — replacing K without addressing the cause", "f": "Hypokalemia with diuretic + vomiting + alkalosis = combined losses + shift; fix the driver", "r": "Hypokalemia = renal loss (diuretics) + GI loss (vomiting) + shift (alkalosis/insulin)", "x": [["A) Only dietary deficiency", "Dietary deficiency alone rarely causes severe hypokalemia this rapidly."], ["B) Only transcellular shift from insulin", "Insulin shift is one factor; the dominant losses here are renal and GI."], ["C) Magnesium excess", "Magnesium excess does not cause hypokalemia; magnesium DEFICIENCY is associated."]]}, {"n": 8, "s": "A 35-year-old non-smoker presents with emphysema predominantly in the lung bases and mild transaminitis. Liver biopsy shows PAS-positive, diastase-resistant globules in hepatocytes. What is the most likely diagnosis?", "o": [["A", "Chronic obstructive pulmonary disease from smoking"], ["B", "Cystic fibrosis"], ["C", "Non-alcoholic fatty liver disease"], ["D", "Alpha-1 antitrypsin deficiency"]], "c": ["D)", "Alpha-1 antitrypsin deficiency"], "co": "Alpha-1 antitrypsin deficiency — PAS+ globules, basal emphysema", "ct": "Analysis/synthesis", "w": "Alpha-1 antitrypsin deficiency causes early-onset panacinar (basal) emphysema and liver disease from accumulated misfolded AAT in hepatocytes (PAS-positive, diastase-resistant globules). The combination of basal emphysema in a non-smoker plus these globules is diagnostic.", "d": "Non-smoker + basal emphysema + PAS-positive diastase-resistant globules = alpha-1 antitrypsin deficiency", "t": "Clinical Mimic — alpha-1 vs smoking-related COPD (basal vs apical emphysema)", "f": "Non-smoker + basal emphysema + PAS+ globules = alpha-1 antitrypsin deficiency", "r": "Alpha-1 antitrypsin deficiency = basal emphysema + PAS+ diastase-resistant hepatic globules", "x": [["A) Chronic obstructive pulmonary disease from smoking", "Smoking-related emphysema is apical and occurs in smokers, without the hepatic globules."], ["B) Cystic fibrosis", "Cystic fibrosis causes bronchiectasis and pancreatic insufficiency, not basal emphysema with hepatic globules."], ["C) Non-alcoholic fatty liver disease", "NAFLD shows steatosis (fat), not PAS-positive diastase-resistant globules."]]}, {"n": 9, "s": "A 28-year-old woman with chronic diarrhoea and weight loss has a negative anti-tTG IgA test, but coeliac disease is still suspected. Which additional test should be checked?", "o": [["A", "Anti-gliadin antibody"], ["B", "Serum vitamin B12"], ["C", "Faecal elastase"], ["D", "Total serum IgA level"]], "c": ["D)", "Total serum IgA level"], "co": "Coeliac disease — IgA deficiency causes false-negative anti-tTG", "ct": "Interpretation", "w": "Selective IgA deficiency (present in 2-3% of coeliac patients) makes anti-tTG IgA falsely negative. When coeliac is suspected despite a negative anti-tTG IgA, measure total IgA; if deficient, use IgG-based serology (anti-tTG IgG or deamidated gliadin peptide IgG) and proceed to biopsy.", "d": "Negative anti-tTG IgA + suspected coeliac → check total IgA (IgA deficiency causes false negatives)", "t": "One-word discriminator — IgA deficiency behind a negative anti-tTG", "f": "Negative anti-tTG but still suspicious = check total IgA (then IgG-based tests + biopsy)", "r": "IgA deficiency → false-negative anti-tTG IgA → check total IgA, use IgG serology", "x": [["A) Anti-gliadin antibody", "Anti-gliadin antibody is outdated and less specific than anti-tTG."], ["B) Serum vitamin B12", "Vitamin B12 does not explain a negative anti-tTG."], ["C) Faecal elastase", "Faecal elastase tests pancreatic function, not coeliac serology."]]}, {"n": 10, "s": "A 55-year-old hypertensive man has sudden vertigo, vomiting, ataxia and headache. He is drowsy. CT shows a cerebellar haemorrhage (3 cm) with early obstructive hydrocephalus. What is the most appropriate management?", "o": [["A", "Medical observation with serial imaging"], ["B", "IV thrombolysis"], ["C", "Urgent posterior fossa surgical decompression"], ["D", "Intravenous steroids and observation"]], "c": ["C)", "Urgent posterior fossa surgical decompression"], "co": "Cerebellar haemorrhage — surgical decompression for mass effect", "ct": "Analysis/synthesis", "w": "A large cerebellar haemorrhage with mass effect, hydrocephalus, or declining conscious level can cause rapid brainstem compression and herniation; urgent surgical decompression (and often EVD) is life-saving.", "d": "Cerebellar bleed + drowsiness/hydrocephalus = surgical emergency", "t": "Treating a haemorrhage 'medically' as if it were ischaemic, or awaiting resolution", "f": "Cerebellar haemorrhage + hydrocephalus/decreasing GCS = operative emergency, not a wait-and-see lesion", "r": "Cerebellar haemorrhage with hydrocephalus, mass effect or reduced consciousness needs urgent posterior fossa decompression; do not delay with observation.", "x": [["A) Medical observation with serial imaging", "observation risks rapid brainstem compression/herniation once hydrocephalus or drowsiness appears"], ["B) IV thrombolysis", "thrombolysis is for ischaemic stroke and is absolutely contraindicated in haemorrhage"], ["D) Intravenous steroids and observation", "steroids do not relieve acute posterior fossa mass effect from haemorrhage and delay definitive surgery"]]}, {"n": 11, "s": "A 48-year-old overweight man has a fasting glucose of 110 mg/dL and a 2-hour post-glucose value of 150 mg/dL on OGTT. HbA1c is 5.9%. What is the correct classification and first step?", "o": [["A", "Diabetes mellitus — start metformin"], ["B", "Normal — no action needed"], ["C", "Gestational diabetes"], ["D", "Prediabetes (impaired fasting glucose / impaired glucose tolerance) — lifestyle modification"]], "c": ["D)", "Prediabetes (impaired fasting glucose / impaired glucose tolerance) — lifestyle modification"], "co": "Prediabetes — IFG (fasting 100-125) / IGT (2h 140-199); lifestyle first", "ct": "Interpretation", "w": "Prediabetes is defined by intermediate values: impaired fasting glucose (fasting 100-125 mg/dL), impaired glucose tolerance (2-h OGTT 140-199 mg/dL), or HbA1c 5.7-6.4%. It is not yet diabetes, so first-line management is intensive lifestyle modification (diet, exercise, weight loss) to prevent progression; metformin is reserved for high-risk individuals. Annual screening is advised.", "d": "Fasting 110 (IFG) + 2h 150 (IGT) + HbA1c 5.9% = prediabetes → lifestyle, not metformin yet", "t": "Unit/Number — IFG 100-125, IGT 2h 140-199, HbA1c 5.7-6.4% = prediabetes", "f": "Fasting 100-125 / 2h 140-199 / HbA1c 5.7-6.4% = prediabetes → lifestyle first", "r": "Prediabetes: IFG (100-125), IGT (2h 140-199), HbA1c 5.7-6.4%; lifestyle modification first-line", "x": [["A) Diabetes mellitus — start metformin", "These values are below diabetes thresholds; metformin is not first-line for prediabetes generally."], ["B) Normal — no action needed", "Prediabetes warrants lifestyle intervention to prevent progression."], ["C) Gestational diabetes", "GDM is pregnancy-specific; this is an OGTT in a non-pregnant adult."]]}, {"n": 12, "s": "A 70-year-old woman on a thiazide diuretic for hypertension presents with confusion. Serum sodium is 122 mmol/L. She is clinically volume-depleted. Which mechanism best explains the hyponatremia?", "o": [["A", "Syndrome of inappropriate ADH (SIADH)"], ["B", "Cerebral salt wasting"], ["C", "Thiazide-induced volume depletion with impaired free-water excretion"], ["D", "Adrenal insufficiency"]], "c": ["C)", "Thiazide-induced volume depletion with impaired free-water excretion"], "co": "Hypovolemic hyponatremia — thiazide causes Na loss and volume depletion", "ct": "Interpretation", "w": "Thiazides cause natriuresis → volume depletion → non-osmotic ADH release → water retention and hyponatremia. The patient is hypovolemic (not euvolemic as in SIADH). Urine sodium is typically low (<20 mmol/L) because the kidney conserves Na in the context of volume depletion. Management is volume repletion.", "d": "Thiazide + volume depletion + low U Na = hypovolemic hyponatremia (not SIADH, which is euvolemic)", "t": "Clinical Mimic — thiazide hyponatremia (hypovolemic) vs SIADH (euvolemic, high U Na)", "f": "Diuretic + volume depletion + low U Na = hypovolemic hyponatremia → replace volume", "r": "Thiazide hyponatremia = volume depletion; SIADH = euvolemic with high urine Na", "x": [["A) Syndrome of inappropriate ADH (SIADH)", "SIADH is euvolemic with inappropriately high urine sodium (>20-30)."], ["B) Cerebral salt wasting", "Cerebral salt wasting also causes volume depletion but follows SAH, not diuretics."], ["D) Adrenal insufficiency", "Adrenal insufficiency causes hyponatremia with hyperkalemia, not isolated thiazide use."]]}, {"n": 13, "s": "A 6-month-old exclusively breastfed infant develops a rash around the mouth and perineum, diarrhoea, and failure to thrive. Which deficiency is most likely?", "o": [["A", "Iron deficiency"], ["B", "Vitamin A deficiency"], ["C", "Vitamin D deficiency"], ["D", "Zinc deficiency"]], "c": ["D)", "Zinc deficiency"], "co": "Zinc deficiency — acrodermatitis enteropathica pattern", "ct": "Interpretation", "w": "Zinc deficiency (hereditary acrodermatitis enteropathica or dietary) causes a characteristic periorificial and acral dermatitis, diarrhoea, and failure to thrive. Breast milk can be low in zinc in some mothers. Treatment is zinc supplementation.", "d": "Periorificial + acral rash + diarrhoea + failure to thrive in infancy = zinc deficiency", "t": "Clinical Mimic — zinc (periorificial rash) vs other micronutrient deficiencies", "f": "Periorificial rash + diarrhoea + failure to thrive = zinc deficiency (acrodermatitis enteropathica)", "r": "Zinc deficiency = periorificial/acral rash + diarrhoea + failure to thrive → zinc supplementation", "x": [["A) Iron deficiency", "Iron deficiency causes pallor and microcytic anaemia, not periorificial dermatitis."], ["B) Vitamin A deficiency", "Vitamin A deficiency causes night blindness and xerophthalmia, not periorificial rash."], ["C) Vitamin D deficiency", "Vitamin D deficiency causes rickets (bony changes), not dermatitis."]]}, {"n": 14, "s": "A 55-year-old man with cirrhosis presents with confusion and asterixis. Serum ammonia is elevated. In the liver, ammonia is detoxified by combining with which molecule to form glutamine?", "o": [["A", "Aspartate"], ["B", "Alanine"], ["C", "Glutamate"], ["D", "Pyruvate"]], "c": ["C)", "Glutamate"], "co": "Hepatic encephalopathy — ammonia detoxification via glutamine synthetase", "ct": "Interpretation", "w": "In the liver (and muscle), glutamine synthetase converts ammonia + glutamate into glutamine, the main non-toxic carrier of ammonia. In cirrhosis this pathway is impaired, so ammonia rises and crosses into the brain, causing hepatic encephalopathy.", "d": "Ammonia + glutamate → glutamine (glutamine synthetase) is the liver's detoxification pathway", "t": "Synonym Swap — glutamate vs glutamine vs aspartate", "f": "Ammonia + glutamate = glutamine (glutamine synthetase) — the NH3→glutamine pair", "r": "NH3 detoxified to glutamine via glutamine synthetase (glutamate is the acceptor)", "x": [["A) Aspartate", "Aspartate feeds the urea cycle (with citrulline → argininosuccinate), not glutamine formation."], ["B) Alanine", "Alanine carries ammonia from muscle to liver (glucose-alanine cycle), not the acceptor for glutamine."], ["D) Pyruvate", "Pyruvate is not the nitrogen acceptor for ammonia detoxification."]]}, {"n": 15, "s": "A 58-year-old type 2 diabetic has persistent fasting hyperglycaemia on maximal oral therapy. Which insulin regimen is most appropriate to start?", "o": [["A", "Three-times-daily prandial rapid-acting only"], ["B", "Stop all oral agents and start biphasic twice daily immediately"], ["C", "IV insulin infusion as outpatient"], ["D", "Once-daily basal (long-acting, e.g. glargine) to target fasting glucose"]], "c": ["D)", "Once-daily basal (long-acting, e.g. glargine) to target fasting glucose"], "co": "Insulin initiation — start basal (long-acting) for fasting hyperglycaemia", "ct": "Interpretation", "w": "When oral therapy no longer controls glycaemia, especially with predominant fasting hyperglycaemia, the standard initiation step is adding a once-daily basal (long-acting, e.g., glargine/detemir) insulin while continuing oral agents. This is simpler and lower-hypo-risk than jumping to multiple daily injections. Rapid-acting/prandial or biphasic regimens are added later if post-prandial control remains poor. IV insulin is for inpatient acute management.", "d": "Persistently high fasting glucose on orals → add once-daily basal (glargine) first", "t": "Treatment ladder — start basal (glargine) for fasting hyperglycaemia, not MDI first", "f": "Fasting hyperglycaemia on orals → add once-daily basal insulin (glargine) first", "r": "Insulin start: once-daily basal (long-acting) for fasting hyperglycaemia; prandial added later", "x": [["A) Three-times-daily prandial rapid-acting only", "Prandial-only without basal leaves fasting glucose uncontrolled."], ["B) Stop all oral agents and start biphasic twice daily immediately", "Immediate biphasic MDI is more complex than needed as a first step."], ["C) IV insulin infusion as outpatient", "IV insulin is inpatient/acute, not an outpatient initiation."]]}, {"n": 16, "s": "A 60-year-old man on amiodarone for atrial fibrillation develops thyrotoxicosis with a low uptake on radioactive iodine scan. What is the most likely mechanism?", "o": [["A", "Type 1 (iodine-induced excess synthesis)"], ["B", "Graves disease"], ["C", "Type 2 amiodarone-induced thyroiditis (destructive)"], ["D", "Subacute thyroiditis"]], "c": ["C)", "Type 2 amiodarone-induced thyroiditis (destructive)"], "co": "Amiodarone thyroid — type 2 = destructive thyroiditis (low uptake), steroids", "ct": "Analysis/synthesis", "w": "Amiodarone causes two patterns: type 1 (iodine-induced excess hormone synthesis in nodular glands, HIGH uptake, treat with antithyroid drugs) and type 2 (destructive thyroiditis from amiodarone toxicity, LOW uptake, treat with steroids). A low uptake scan points to type 2. Distinguishing them guides therapy.", "d": "Amiodarone + thyrotoxicosis + LOW RAI uptake = type 2 (destructive); type 1 (high uptake) = iodine excess", "t": "Opposite — type 1 (high uptake, antithyroid) vs type 2 (low uptake, steroids)", "f": "Amiodarone thyrotoxicosis: low uptake = type 2 (destructive, steroids); high uptake = type 1 (antithyroid)", "r": "Amiodarone thyroid: type 2 = destructive (low uptake) → steroids; type 1 = iodine excess (high uptake) → antithyroid", "x": [["A) Type 1 (iodine-induced excess synthesis)", "Type 1 shows HIGH uptake and is treated with antithyroid drugs, not steroids."], ["B) Graves disease", "Graves would show diffuse high uptake and TSAb, not amiodarone exposure."], ["D) Subacute thyroiditis", "Subacute (de Quervain) thyroiditis is post-viral, not drug-induced."]]}, {"n": 17, "s": "A 68-year-old man with no renal disease has a reported potassium of 6.9 mmol/L, but he is asymptomatic with a normal ECG. Repeat testing after a drawing technique change shows 4.4 mmol/L. What happened?", "o": [["A", "True hyperkalemia now resolved"], ["B", "Laboratory error in calibration"], ["C", "Medication-induced shift"], ["D", "Pseudohyperkalemia from hemolysis/fist clenching"]], "c": ["D)", "Pseudohyperkalemia from hemolysis/fist clenching"], "co": "Pseudohyperkalemia — artifact from hemolysis or prolonged tourniquet/fist clenching", "ct": "Interpretation", "w": "Pseudohyperkalemia arises from potassium release during or after blood draw — hemolysis, prolonged tourniquet, or repeated fist clenching. The patient is asymptomatic with a normal ECG, and a carefully drawn repeat is normal. Recognizing this prevents unnecessary (and dangerous) treatment. True hyperkalemia is rarely asymptomatic at 6.9 mmol/L.", "d": "Asymptomatic 'hyperkalemia' + normal ECG + normal repeat = pseudohyperkalemia (artifact)", "t": "One-word discriminator — pseudohyperkalemia (artifact, asymptomatic)", "f": "Asymptomatic high K + normal ECG + normal repeat = pseudohyperkalemia (draw artifact)", "r": "Pseudohyperkalemia = artifact (hemolysis/fist clench); true hyperK is rarely asymptomatic at 6.9", "x": [["A) True hyperkalemia now resolved", "A value that normalises with technique change is artifact, not a resolved true state."], ["B) Laboratory error in calibration", "Calibration error would affect other electrolytes, not just K."], ["C) Medication-induced shift", "Medication shift would not resolve simply with a better draw technique."]]}, {"n": 18, "s": "A 40-year-old man with severe anorexia is started on aggressive enteral nutrition after a period of starvation. Within 2 days he develops weakness and cardiac arrhythmia. Which electrolyte disturbance is the most likely cause?", "o": [["A", "Hyperkalaemia"], ["B", "Hypernatraemia"], ["C", "Hypermagnesaemia"], ["D", "Hypophosphataemia"]], "c": ["D)", "Hypophosphataemia"], "co": "Refeeding syndrome — hypophosphataemia", "ct": "Analysis/synthesis", "w": "Refeeding syndrome occurs when carbohydrate refeeding after starvation triggers an insulin surge, driving phosphate (plus potassium and magnesium) into cells, causing hypophosphataemia with weakness, arrhythmia, and cardiac failure. Prevention is slow, gradual refeeding with phosphate monitoring.", "d": "Rapid refeeding after starvation → insulin surge → intracellular shift → hypophosphataemia → arrhythmia", "t": "Severity under-recognition — refeeding complication missed after starting feeds", "f": "Refeeding after starvation → watch phosphate (and K/Mg); refeed slowly", "r": "Refeeding syndrome = hypophosphataemia (and low K/Mg) after rapid refeeding → slow, monitored refeeding", "x": [["A) Hyperkalaemia", "Refeeding causes hypokalaemia (intracellular shift), not hyperkalaemia."], ["B) Hypernatraemia", "Hypernatraemia is not the classic refeeding disturbance."], ["C) Hypermagnesaemia", "Refeeding causes hypomagnesaemia, not hypermagnesaemia."]]}, {"n": 19, "s": "A 45-year-old man with hepatitis B-related cirrhosis is under surveillance. What is the most appropriate screening strategy for hepatocellular carcinoma?", "o": [["A", "Annual CT abdomen"], ["B", "Six-monthly MRI liver"], ["C", "Six-monthly ultrasound with alpha-fetoprotein"], ["D", "Annual ultrasound alone"]], "c": ["C)", "Six-monthly ultrasound with alpha-fetoprotein"], "co": "Hepatocellular carcinoma — surveillance in cirrhosis", "ct": "Interpretation", "w": "Patients with cirrhosis are screened for hepatocellular carcinoma every 6 months with ultrasound, with or without alpha-fetoprotein. CT/MRI are diagnostic (used when a lesion is found), not surveillance tools.", "d": "Cirrhosis (HBV) → 6-monthly ultrasound + AFP for HCC surveillance", "t": "Unit/Number — 6-monthly interval + US over CT/MRI for screening", "f": "Cirrhosis = HCC surveillance with 6-monthly US (+AFP); CT/MRI only to characterise a lesion", "r": "HCC surveillance in cirrhosis = 6-monthly ultrasound (+AFP)", "x": [["A) Annual CT abdomen", "Annual CT is not the surveillance standard and CT is a diagnostic, not screening, tool."], ["B) Six-monthly MRI liver", "MRI is diagnostic (not screening) and too costly for routine surveillance."], ["D) Annual ultrasound alone", "The standard interval is 6-monthly, not annual; AFP may be added."]]}, {"n": 20, "s": "A 12-year-old girl with recurrent urinary tract infections and hypertension has renal scarring on DMSA scan, most prominent at the upper and lower poles. What is the most likely underlying problem?", "o": [["A", "Posterior urethral valves"], ["B", "Renal artery stenosis"], ["C", "Autosomal dominant polycystic kidney disease"], ["D", "Vesicoureteral reflux"]], "c": ["D)", "Vesicoureteral reflux"], "co": "Reflux nephropathy — VUR causes polar renal scarring", "ct": "Interpretation", "w": "Vesicoureteral reflux causes reflux nephropathy: infected urine refluxes into the kidney, producing focal scarring at the poles (intrarenal reflux), recurrent UTIs, hypertension, and progressive CKD. Diagnosis is by micturating cystourethrography; management includes antibiotic prophylaxis and surgical correction for high-grade reflux.", "d": "Recurrent UTIs + HTN + polar scarring on DMSA = vesicoureteral reflux (reflux nephropathy)", "t": "Clinical Mimic — reflux nephropathy (polar scarring) vs other CKD causes", "f": "Recurrent UTIs + HTN + polar scarring = vesicoureteral reflux (reflux nephropathy)", "r": "VUR → reflux nephropathy: recurrent UTIs + polar renal scarring + HTN", "x": [["A) Posterior urethral valves", "Posterior urethral valves cause obstruction in male infants, not polar scarring."], ["B) Renal artery stenosis", "Renal artery stenosis causes hypertension without recurrent UTIs."], ["C) Autosomal dominant polycystic kidney disease", "ADPKD causes cysts, not polar scarring."]]}, {"n": 21, "s": "A 70-year-old man with septic shock has a high anion gap metabolic acidosis, elevated lactate (8 mmol/L), and low bicarbonate. Which is the primary mechanism?", "o": [["A", "Type B lactic acidosis from metformin"], ["B", "Ketoacidosis"], ["C", "Methanol ingestion"], ["D", "Type A lactic acidosis from tissue hypoperfusion"]], "c": ["D)", "Type A lactic acidosis from tissue hypoperfusion"], "co": "Lactic acidosis — type A from hypoperfusion/shock (MUDPILES 'L')", "ct": "Interpretation", "w": "Lactic acidosis is divided into type A (tissue hypoperfusion / hypoxia / shock — the common, dangerous form in sepsis) and type B (metabolic, e.g., metformin, malignancies, toxins). The elevated lactate with shock points to type A; treatment is restoring perfusion, not just buffering. Within MUDPILES, 'L' = lactate.", "d": "Shock + high AG acidosis + high lactate = type A lactic acidosis (hypoperfusion)", "t": "Severity under-recognition — lactate as perfusion marker in shock", "f": "Shock + high AG + high lactate = type A lactic acidosis → restore perfusion", "r": "Type A lactic acidosis = hypoperfusion/shock (treat perfusion); type B = metformin/toxins", "x": [["A) Type B lactic acidosis from metformin", "Metformin causes type B lactic acidosis, not shock-driven type A."], ["B) Ketoacidosis", "Ketoacidosis has ketones; lactate here is the driver."], ["C) Methanol ingestion", "Methanol causes high AG acidosis with an osmolal gap and ocular toxicity."]]}, {"n": 22, "s": "A 19-year-old non-obese woman with a strong family history of diabetes (autosomal dominant) presents with mild hyperglycaemia. She is not ketosis-prone and her C-peptide is normal. Which feature best fits maturity-onset diabetes of the young (MODY)?", "o": [["A", "Obesity with insulin resistance"], ["B", "Autoantibodies positive, prone to ketoacidosis"], ["C", "Young onset, lean, autosomal dominant inheritance, often sulfonylurea-responsive"], ["D", "Pancreatic exocrine insufficiency"]], "c": ["C)", "Young onset, lean, autosomal dominant inheritance, often sulfonylurea-responsive"], "co": "MODY — young, lean, AD inheritance, sulfonylurea-responsive", "ct": "Interpretation", "w": "MODY is a monogenic (usually HNF1A/glucokinase) autosomal dominant form of diabetes presenting in young, often lean individuals who are C-peptide positive (not ketosis-prone). It is frequently responsive to sulfonylureas rather than insulin. The autosomal dominant family history and lack of obesity/autoimmunity distinguish it from type 1 and type 2 diabetes.", "d": "Young lean diabetic + autosomal dominant family history + C-peptide intact = MODY (not T1/T2)", "t": "Clinical Mimic — MODY (young, lean, AD, C-peptide+) vs type 1 (autoimmune) / type 2 (obese)", "f": "Young lean diabetic + AD family history + intact C-peptide = MODY (sulfonylurea-responsive)", "r": "MODY: young, lean, autosomal dominant, C-peptide positive; often sulfonylurea-responsive (HNF1A)", "x": [["A) Obesity with insulin resistance", "Obesity/insulin resistance suggests type 2 diabetes, not the typical MODY profile."], ["B) Autoantibodies positive, prone to ketoacidosis", "Autoantibodies and ketoacidosis suggest type 1 diabetes, not MODY."], ["D) Pancreatic exocrine insufficiency", "Exocrine insufficiency suggests type 3c (pancreatogenic) diabetes."]]}, {"n": 23, "s": "A 9-year-old boy has slowed growth, bitemporal hemianopia, and a calcified suprasellar mass on CT. What is the most likely diagnosis?", "o": [["A", "Pituitary adenoma"], ["B", "Meningioma"], ["C", "Glioma of the optic nerve"], ["D", "Craniopharyngioma"]], "c": ["D)", "Craniopharyngioma"], "co": "Craniopharyngioma — child, calcified suprasellar mass, bitemporal hemianopia", "ct": "Interpretation", "w": "Craniopharyngioma is a benign but locally aggressive tumour arising from Rathke pouch, typically in children/young adults, presenting with a calcified suprasellar mass causing bitemporal hemianopia (chiasmal compression) and hypothalamic/pituitary hormone deficiencies (growth failure). Treatment is surgical resection, often with radiotherapy; diabetes insipidus commonly follows.", "d": "Child + calcified suprasellar mass + bitemporal hemianopia + growth failure = craniopharyngioma", "t": "Clinical Mimic — craniopharyngioma (calcified suprasellar, child) vs pituitary adenoma", "f": "Child + calcified suprasellar mass + bitemporal hemianopia = craniopharyngioma", "r": "Craniopharyngioma: child + calcified suprasellar mass + bitemporal hemianopia + hormone deficits", "x": [["A) Pituitary adenoma", "Pituitary adenomas are rarely calcified and usually present in adults, not with this mass in a child."], ["B) Meningioma", "Meningiomas are extra-axial and uncommon in children, and less often calcified suprasellar."], ["C) Glioma of the optic nerve", "Optic nerve glioma causes unilateral vision loss, not bitemporal hemianopia with a calcified mass."]]}, {"n": 24, "s": "In assessing the nutritional status of an acutely ill hospitalised patient, which protein best reflects recent (short-term) nutritional change?", "o": [["A", "Albumin"], ["B", "Ferritin"], ["C", "Transferrin"], ["D", "Prealbumin (transthyretin)"]], "c": ["D)", "Prealbumin (transthyretin)"], "co": "Nutritional assessment — prealbumin vs albumin", "ct": "Interpretation", "w": "Prealbumin (transthyretin) has a half-life of ~2 days, so it reflects recent nutritional change. Albumin has a long half-life (~20 days) and falls in inflammation (a negative acute-phase reactant), making it a poor marker of short-term nutrition in acute illness.", "d": "Prealbumin has a short half-life (~2 days) → reflects recent nutritional change better than albumin", "t": "Unit/Number — half-life (prealbumin 2 days vs albumin 20 days)", "f": "Short-term nutrition marker = prealbumin (2-day half-life); albumin lags and falls in inflammation", "r": "Prealbumin (t½ ~2 days) reflects short-term nutrition; albumin (t½ ~20 days) is confounded by inflammation", "x": [["A) Albumin", "Albumin has a long half-life and falls with inflammation, not reflecting acute nutritional change."], ["B) Ferritin", "Ferritin reflects iron stores, not general nutrition."], ["C) Transferrin", "Transferrin is affected by iron status and has a longer half-life than prealbumin."]]}, {"n": 25, "s": "A 35-year-old man is found to have the following serology: HBsAg positive, anti-HBc IgG positive, anti-HBs negative, HBeAg negative, with normal ALT. What does this profile indicate?", "o": [["A", "Immunity from vaccination"], ["B", "Acute hepatitis B infection"], ["C", "Chronic hepatitis B infection"], ["D", "Resolved hepatitis B infection"]], "c": ["C)", "Chronic hepatitis B infection"], "co": "Hepatitis B serology — chronic infection profile", "ct": "Analysis/synthesis", "w": "HBsAg positive for more than 6 months with anti-HBc IgG and negative anti-HBs indicates chronic hepatitis B infection. Immunity from vaccination shows anti-HBs alone; acute infection shows anti-HBc IgM; resolved infection shows anti-HBs+ and anti-HBc IgG+ with HBsAg negative.", "d": "HBsAg+ + anti-HBc IgG+ + anti-HBs− = chronic infection (HBsAg persists >6 months)", "t": "Synonym Swap — chronic vs resolved vs vaccinated serology", "f": "HBsAg+ anti-HBc+ anti-HBs− = chronic; anti-HBs only = vaccinated; anti-HBs+ HBsAg− = resolved", "r": "Chronic HBV = HBsAg+ (>6mo), anti-HBc IgG+, anti-HBs−", "x": [["A) Immunity from vaccination", "Vaccination produces anti-HBs alone (no HBsAg or anti-HBc)."], ["B) Acute hepatitis B infection", "Acute infection shows anti-HBc IgM positive, not IgG, with HBsAg."], ["D) Resolved hepatitis B infection", "Resolved infection is HBsAg negative with anti-HBs and anti-HBc IgG positive."]]}, {"n": 26, "s": "A 78-year-old woman on digoxin presents with nausea, bradycardia, and a potassium of 6.4 mmol/L. Which is the most appropriate acute management?", "o": [["A", "IV calcium gluconate immediately"], ["B", "Insulin and dextrose alone"], ["C", "Potassium supplementation"], ["D", "Digoxin-specific antibody fragments (Fab); avoid giving calcium"]], "c": ["D)", "Digoxin-specific antibody fragments (Fab); avoid giving calcium"], "co": "Digoxin toxicity — hyperkalemia is a marker; treat with Digoxin-Fab, avoid calcium", "ct": "Analysis/synthesis", "w": "In acute digoxin toxicity, hyperkalemia reflects blocked Na/K-ATPase and correlates with severity; potassium-lowering (especially insulin) and Digoxin-specific antibody fragments (Fab) are indicated. Calcium is traditionally AVOIDED in digoxin toxicity because it can precipitate severe dysrhythmia ('stone heart'). This contrasts with non-digoxin hyperkalemia, where calcium is first-line for ECG changes.", "d": "Digoxin toxicity hyperkalemia = give Digoxin-Fab; AVOID calcium (risk of 'stone heart')", "t": "Treatment misdirection — giving calcium in digoxin toxicity (harmful)", "f": "Digoxin toxicity + high K = Digoxin-Fab; do NOT give calcium (unlike other hyperK)", "r": "Digoxin toxicity hyperkalemia → Digoxin-Fab; avoid calcium (risk of 'stone heart')", "x": [["A) IV calcium gluconate immediately", "Calcium is avoided in digoxin toxicity due to arrhythmia risk."], ["B) Insulin and dextrose alone", "Insulin/dextrose may be used but Fab is definitive; calcium is the key avoided agent."], ["C) Potassium supplementation", "Potassium would worsen toxicity; it is already elevated."]]}, {"n": 27, "s": "A 40-year-old diabetic woman has recurrent early satiety, nausea, vomiting of undigested food, and bloating, with glycaemic instability. Gastroscopy is normal. What is the most likely mechanism?", "o": [["A", "Peptic ulcer disease"], ["B", "Autonomic (vagal) neuropathy causing gastroparesis"], ["C", "Mechanical gastric outlet obstruction"], ["D", "Pancreatic exocrine insufficiency"]], "c": ["B)", "Autonomic (vagal) neuropathy causing gastroparesis"], "co": "Diabetic gastroparesis — autonomic neuropathy, delayed gastric emptying", "ct": "Interpretation", "w": "Diabetic autonomic neuropathy can involve the vagus, causing gastroparesis — delayed gastric emptying with early satiety, nausea, vomiting of old food, and erratic glucose absorption. Endoscopy is typically normal (rule out obstruction/ulcer). Management is glycaemic control, small frequent meals, prokinetics (metoclopramide/erythromycin), and antiemetics.", "d": "Nausea/vomiting undigested food + normal endoscopy + DM = gastroparesis (vagal neuropathy)", "t": "Clinical Mimic — gastroparesis (autonomic neuropathy) vs mechanical obstruction/PUD", "f": "Nausea + vomiting undigested food + normal scope in DM = gastroparesis (vagal neuropathy)", "r": "Diabetic gastroparesis: vagal autonomic neuropathy → delayed emptying; normal endoscopy; prokinetics", "x": [["A) Peptic ulcer disease", "PUD would show a lesion on endoscopy, which was normal here."], ["C) Mechanical gastric outlet obstruction", "Mechanical obstruction would show a luminal block on scope/imaging."], ["D) Pancreatic exocrine insufficiency", "Pancreatic insufficiency causes steatorrhea, not vomiting of undigested food."]]}, {"n": 28, "s": "A 45-year-old woman had a total thyroidectomy for papillary thyroid carcinoma and is on thyroxine. Three months later, while on thyroxine, her thyroglobulin is undetectable but anti-thyroglobulin antibodies are negative. What does this indicate?", "o": [["A", "Definite metastatic recurrence"], ["B", "Inadequate thyroxine dose"], ["C", "No evidence of residual/recurrent disease"], ["D", "Need for repeat surgery now"]], "c": ["C)", "No evidence of residual/recurrent disease"], "co": "Differentiated thyroid Ca — thyroglobulin as tumour marker (undetectable = no disease)", "ct": "Interpretation", "w": "After total thyroidectomy (and usually radioiodine ablation) for differentiated (papillary/follicular) thyroid carcinoma, thyroglobulin is the tumour marker. An undetectable thyroglobulin (with negative anti-thyroglobulin antibodies, which otherwise cause false lows) indicates no residual or recurrent disease. Rising thyroglobulin signals recurrence. TSH is suppressed to reduce stimulation.", "d": "Post-thyroidectomy: undetectable thyroglobulin (+ negative antibodies) = no residual disease", "t": "One-word discriminator — thyroglobulin = differentiated thyroid Ca tumour marker", "f": "Post-op undetectable thyroglobulin (antibodies negative) = no residual thyroid Ca", "r": "Differentiated thyroid Ca: thyroglobulin = tumour marker; undetectable (no Ab) = no recurrence", "x": [["A) Definite metastatic recurrence", "Undetectable thyroglobulin argues against recurrence, not for it."], ["B) Inadequate thyroxine dose", "Thyroglobulin is a tumour marker, not a measure of thyroxine adequacy (TSH is)."], ["D) Need for repeat surgery now", "No evidence of disease does not warrant repeat surgery."]]}, {"n": 29, "s": "A 28-year-old man with known ulcerative colitis presents with fever, tachycardia, abdominal distension, and dilated colon (>6 cm) on abdominal X-ray. What is the most appropriate initial management?", "o": [["A", "Oral loperamide"], ["B", "Oral mesalazine and discharge"], ["C", "Barium enema"], ["D", "IV fluids, IV corticosteroids, and surgical review"]], "c": ["D)", "IV fluids, IV corticosteroids, and surgical review"], "co": "Toxic megacolon — complication of UC", "ct": "Analysis/synthesis", "w": "Toxic megacolon is a life-threatening complication of ulcerative colitis (dilatation >6 cm with systemic toxicity). Management is resuscitation, IV corticosteroids, broad-spectrum antibiotics, and early surgical referral for colectomy if no response. Loperamide and barium are contraindicated.", "d": "UC + fever + tachycardia + colonic dilatation >6 cm = toxic megacolon → IV steroids + resuscitation + surgical review", "t": "Severity under-recognition — 'just diarrhoea' downgrade in a UC patient", "f": "UC + distension + fever + dilated colon = toxic megacolon → IV steroids + surgical review, no loperamide", "r": "Toxic megacolon (UC) → resuscitate + IV steroids + early colectomy if no response", "x": [["A) Oral loperamide", "Loperamide is contraindicated — it worsens dilatation and perforation risk."], ["B) Oral mesalazine and discharge", "Mesalazine and discharge are inadequate for a life-threatening complication."], ["C) Barium enema", "Barium enema risks perforation in a dilated inflamed colon."]]}, {"n": 30, "s": "A pregnant woman with chronic hepatitis B (HBsAg positive) delivers a baby. After giving hepatitis B immunoglobulin, what additional step most effectively prevents transmission?", "o": [["A", "First dose of hepatitis B vaccine within 12-24 hours of birth"], ["B", "Breastfeeding avoidance"], ["C", "Caesarean delivery"], ["D", "Defer vaccination until 6 weeks"]], "c": ["A)", "First dose of hepatitis B vaccine within 12-24 hours of birth"], "co": "Hepatitis B — vertical transmission prevention", "ct": "Interpretation", "w": "For an HBsAg-positive mother, the baby receives hepatitis B immunoglobulin plus the first dose of hepatitis B vaccine within 12-24 hours of birth, followed by the full series. This reduces vertical transmission from ~90% to <5%. Breastfeeding is safe after immunoprophylaxis.", "d": "HBsAg+ mother → HBIG + first vaccine dose within 12-24 hours of birth", "t": "Unit/Number — timing (12-24h) is the discriminator", "f": "HBsAg+ mother = HBIG + vaccine within 12-24h of birth (breastfeeding is safe)", "r": "Hep B vertical: HBIG + first vaccine dose within 12-24h of birth", "x": [["B) Breastfeeding avoidance", "Breastfeeding is not contraindicated once the infant receives HBIG and vaccine."], ["C) Caesarean delivery", "Caesarean delivery does not reduce HBV transmission."], ["D) Defer vaccination until 6 weeks", "Delaying vaccination increases the risk of perinatal infection."]]}, {"n": 31, "s": "A 50-year-old woman undergoes resection of 100 cm of terminal ileum for Crohn disease. Which two deficiencies is she most at risk of developing?", "o": [["A", "Iron and folate deficiency"], ["B", "Vitamin B12 and bile salt malabsorption"], ["C", "Vitamin C and zinc deficiency"], ["D", "Vitamin D and calcium deficiency"]], "c": ["B)", "Vitamin B12 and bile salt malabsorption"], "co": "Ileal resection — B12 and bile salt malabsorption", "ct": "Interpretation", "w": "The terminal ileum is the site of vitamin B12 absorption (intrinsic factor receptor) and bile salt reabsorption. Ileal resection therefore causes B12 deficiency (macrocytic anaemia, neuropathy) and bile salt malabsorption (watery diarrhoea, treated with cholestyramine).", "d": "Terminal ileum absorbs B12 and bile salts → resection causes B12 deficiency + bile salt malabsorption", "t": "Opposite — ileal (B12/bile salt) vs duodenal/jejunal (iron/folate) malabsorption", "f": "Terminal ileum resected = B12 + bile salt deficiency; duodenum = iron; jejunum = folate", "r": "Ileal resection → B12 deficiency + bile salt malabsorption (cholestyramine for diarrhoea)", "x": [["A) Iron and folate deficiency", "Iron (duodenum) and folate (jejunum) are absorbed proximally, not in the ileum."], ["C) Vitamin C and zinc deficiency", "Vitamin C and zinc are not ileum-specific."], ["D) Vitamin D and calcium deficiency", "Vitamin D and calcium absorption are not primarily ileal."]]}, {"n": 32, "s": "A 48-year-old woman on peritoneal dialysis presents with abdominal pain and a cloudy effluent bag. What is the most appropriate initial step?", "o": [["A", "Remove the peritoneal catheter immediately"], ["B", "Switch to haemodialysis permanently"], ["C", "Send effluent for cell count, gram stain, and culture, then start empirical antibiotics"], ["D", "Observe for 48 hours"]], "c": ["C)", "Send effluent for cell count, gram stain, and culture, then start empirical antibiotics"], "co": "Peritoneal dialysis — peritonitis diagnosis and empirical treatment", "ct": "Interpretation", "w": "Peritonitis is the major complication of peritoneal dialysis, presenting with abdominal pain and cloudy effluent (WBC >100/μL). Management is effluent cell count, Gram stain, and culture followed by empirical intraperitoneal antibiotics (covering Gram-positives). Catheter removal is reserved for refractory or fungal peritonitis.", "d": "Cloudy effluent + abdominal pain in PD patient = peritonitis → effluent analysis + empirical antibiotics", "t": "One-word discriminator — cloudy effluent = peritonitis (not catheter removal first)", "f": "PD patient + cloudy effluent + pain = peritonitis → effluent studies + IP antibiotics", "r": "PD peritonitis = cloudy effluent → cell count/culture + empirical IP antibiotics", "x": [["A) Remove the peritoneal catheter immediately", "Catheter removal is reserved for refractory, fungal, or tunnel infections."], ["B) Switch to haemodialysis permanently", "Permanent switch to haemodialysis is not first-line."], ["D) Observe for 48 hours", "Observation delays treatment of a potentially serious infection."]]}, {"n": 33, "s": "A 40-year-old woman in the third trimester develops seizures. Her blood pressure is 160/100 and she has proteinuria. Which magnesium preparation is the treatment of choice for seizure prophylaxis?", "o": [["A", "Calcium gluconate"], ["B", "Magnesium oxide orally"], ["C", "Potassium chloride"], ["D", "Magnesium sulfate"]], "c": ["D)", "Magnesium sulfate"], "co": "Magnesium sulfate — eclampsia / pre-eclampsia seizure prophylaxis", "ct": "Recall", "w": "Magnesium sulfate is the first-line agent for seizure prophylaxis and treatment in pre-eclampsia/eclampsia. It acts as a CNS depressant and vasodilator. Calcium gluconate is the antidote for magnesium toxicity (loss of patellar reflexes, respiratory depression). Magnesium oxide is an oral supplement, not for acute seizures.", "d": "Pre-eclampsia/eclampsia seizures → IV magnesium sulfate (not calcium)", "t": "Treatment ladder — magnesium sulfate for eclampsia; calcium is the ANTIDOTE", "f": "Eclampsia/pre-eclampsia seizures → magnesium sulfate; calcium reverses Mg toxicity", "r": "Eclampsia seizures → IV magnesium sulfate; calcium gluconate is the antidote for Mg toxicity", "x": [["A) Calcium gluconate", "Calcium gluconate reverses magnesium toxicity, not treats eclampsia seizures."], ["B) Magnesium oxide orally", "Oral magnesium oxide is a laxative/supplement, not acute therapy."], ["C) Potassium chloride", "Potassium chloride does not treat eclampsia."]]}, {"n": 34, "s": "A 60-year-old woman started on high-dose oral prednisolone for polymyalgia rheumatica develops fasting hyperglycaemia and glucosuria after 2 weeks. She has no prior diabetes. What is the most likely cause?", "o": [["A", "Type 1 diabetes"], ["B", "Steroid-induced (glucocorticoid) diabetes"], ["C", "Type 2 diabetes newly diagnosed"], ["D", "Phaeochromocytoma"]], "c": ["B)", "Steroid-induced (glucocorticoid) diabetes"], "co": "Steroid-induced diabetes — glucocorticoids raise glucose (hepatic output, insulin resistance)", "ct": "Interpretation", "w": "Glucocorticoids induce hepatic glucose production, reduce peripheral uptake, and cause insulin resistance, producing hyperglycaemia (often post-prandial) — so-called steroid diabetes. It typically resolves after dose reduction/cessation but may need short-term insulin/oral agents while on steroids. Recognising the temporal link prevents misdiagnosis as new type 1/2 diabetes.", "d": "New hyperglycaemia after starting glucocorticoids = steroid-induced diabetes", "t": "Clinical Mimic — hyperglycemia after starting steroids (steroid diabetes) vs new-onset T1/T2", "f": "New hyperglycaemia after glucocorticoid start = steroid-induced diabetes", "r": "Glucocorticoids → hepatic glucose output + insulin resistance → steroid-induced diabetes; monitor glucose", "x": [["A) Type 1 diabetes", "Type 1 would not be temporally linked to steroid initiation."], ["C) Type 2 diabetes newly diagnosed", "New type 2 is possible but the steroid trigger here is the key link."], ["D) Phaeochromocytoma", "Phaeochromocytoma causes episodic hypertension/sweating, not steroid-linked hyperglycaemia."]]}, {"n": 35, "s": "A 55-year-old man with chronic liver disease attends for routine review and is found to have a prolonged prothrombin time. Which supplement most directly addresses this coagulation defect?", "o": [["A", "Folic acid"], ["B", "Vitamin B12"], ["C", "Vitamin C"], ["D", "Vitamin K"]], "c": ["D)", "Vitamin K"], "co": "Vitamin K deficiency in chronic liver disease", "ct": "Recall", "w": "Chronic liver disease impairs fat-soluble vitamin absorption and synthetic function, causing deficiency of vitamin K-dependent clotting factors (II, VII, IX, X) and a prolonged prothrombin time. Vitamin K is the appropriate supplement.", "d": "Prolonged PT in chronic liver disease → vitamin K (fat-soluble vitamin needed for factors II, VII, IX, X)", "t": "Opposite — vitamin K vs other vitamins for coagulopathy", "f": "CLD + prolonged PT = think vitamin K (fat-soluble, factor II/VII/IX/X)", "r": "Vitamin K corrects PT prolongation from factor II/VII/IX/X deficiency in CLD", "x": [["A) Folic acid", "Folic acid treats macrocytic anaemia, not the coagulation defect."], ["B) Vitamin B12", "Vitamin B12 deficiency causes macrocytic anaemia and neuropathy, not PT prolongation."], ["C) Vitamin C", "Vitamin C deficiency causes scurvy, not coagulopathy."]]}, {"n": 36, "s": "A couple presents with infertility. The man has a low semen volume and a left varicocele on exam. Which initial step is most appropriate?", "o": [["A", "Immediate IVF without evaluation"], ["B", "Semen analysis; correct varicocele if present before assisted reproduction"], ["C", "Testosterone replacement"], ["D", "Prostate biopsy"]], "c": ["B)", "Semen analysis; correct varicocele if present before assisted reproduction"], "co": "Male infertility — semen analysis first; varicocele correction improves fertility", "ct": "Interpretation", "w": "Male infertility evaluation begins with semen analysis (count, motility, morphology). A correctable cause such as varicocele should be addressed (varicocelectomy) before pursuing assisted reproduction. Testosterone replacement would SUPPRESS spermatogenesis and worsen infertility. Prostate biopsy is not part of routine infertility workup.", "d": "Infertility workup = semen analysis; varicocele (correctable) is a key reversible cause", "t": "Treatment misdirection — testosterone (suppresses sperm) vs varicocele repair", "f": "Male infertility: semen analysis first; fix varicocele; avoid testosterone (worsens)", "r": "Male infertility: semen analysis; varicocele repair is a reversible cause; testosterone worsens it", "x": [["A) Immediate IVF without evaluation", "IVF without basic evaluation/treatment of reversible causes is premature."], ["C) Testosterone replacement", "Exogenous testosterone suppresses the HPG axis and reduces sperm production."], ["D) Prostate biopsy", "Prostate biopsy is for suspected prostate cancer, not infertility."]]}, {"n": 37, "s": "A 20-year-old presents with a painless, fluctuant swelling in the anterior triangle of the neck, anterior to the sternocleidomastoid. It has been present since childhood and does not move with tongue protrusion. What is it?", "o": [["A", "Thyroglossal duct cyst"], ["B", "Thyroid adenoma"], ["C", "Branchial (pharyngeal) cleft cyst"], ["D", "Carotid body tumour"]], "c": ["C)", "Branchial (pharyngeal) cleft cyst"], "co": "Branchial cleft cyst — lateral neck (anterior triangle), no movement on protrusion", "ct": "Interpretation", "w": "A branchial (second) cleft cyst presents as a soft lateral neck mass in the anterior triangle, anterior to sternocleidomastoid, often noticed in young adults; it does not move with tongue protrusion (that finding localises a thyroglossal cyst). Treatment is surgical excision of the cyst and tract. A branchial SINUS/fistula opens to the skin. Recurrent infection can obscure the diagnosis.", "d": "Lateral neck cyst anterior to SCM, no tongue-protrusion movement = branchial cleft cyst", "t": "Clinical Mimic — branchial (lateral) vs thyroglossal (midline, moves on protrusion)", "f": "Lateral neck cyst, no tongue-protrusion movement = branchial cleft cyst", "r": "Branchial cleft cyst: lateral neck (anterior triangle), no movement on tongue protrusion; excision", "x": [["A) Thyroglossal duct cyst", "A thyroglossal cyst is midline and moves on tongue protrusion."], ["B) Thyroid adenoma", "A thyroid adenoma is a thyroid-gland nodule, not a lateral cervical cyst."], ["D) Carotid body tumour", "Carotid body tumours are at the carotid bifurcation, not simple lateral cysts."]]}, {"n": 38, "s": "A 55-year-old woman with recurrent renal stones is found to have hypercalcaemia with low phosphate and elevated PTH. Which stone type is she forming?", "o": [["A", "Uric acid stones"], ["B", "Cystine stones"], ["C", "Calcium (calcium oxalate / phosphate) stones"], ["D", "Struvite stones"]], "c": ["C)", "Calcium (calcium oxalate / phosphate) stones"], "co": "Primary hyperparathyroidism — hypercalciuria → calcium stones (bones, stones, groans)", "ct": "Interpretation", "w": "Primary hyperparathyroidism causes hypercalcaemia (high Ca, low PO4, high PTH) with hypercalciuria, leading to calcium-containing stones (oxalate or phosphate). The classic mnemonic is 'bones, stones, groans, moans'. Recognising the metabolic profile guides both stone prevention and parathyroid surgery.", "d": "High Ca + low PO4 + high PTH + stones = primary HPT → calcium-containing stones", "t": "Opposite — HPT (high Ca → calcium stones) vs uric acid (low Ca, radiolucent)", "f": "Primary HPT + stones = calcium stones (high Ca/low PO4/high PTH)", "r": "Primary HPT → hypercalciuria → calcium stones (high Ca, low PO4, high PTH)", "x": [["A) Uric acid stones", "Uric acid stones occur with hyperuricaemia, not hypercalcaemia/low phosphate."], ["B) Cystine stones", "Cystine stones are hereditary, not HPT-related."], ["D) Struvite stones", "Struvite stones occur in infected alkaline urine, not HPT."]]}, {"n": 39, "s": "A 66-year-old man undergoes an uneventful right hemicolectomy for colon cancer. Histology reports a moderately differentiated adenocarcinoma extending through the muscularis propria into pericolonic tissue (pT3), with 3 of 14 lymph nodes positive (pN1b) and no metastases (M0). What is the most appropriate further management?", "o": [["A", "Observation alone with surveillance"], ["B", "Adjuvant chemotherapy"], ["C", "Neoadjuvant chemoradiotherapy followed by surgery"], ["D", "Palliative chemotherapy"]], "c": ["B)", "Adjuvant chemotherapy"], "co": "Colon cancer — adjuvant treatment of stage III disease", "ct": "Analysis/synthesis (stage III → adjuvant chemotherapy)", "w": "Positive regional lymph nodes make this stage III colon cancer, for which adjuvant chemotherapy meaningfully improves survival; radiotherapy is not used for colon primaries.", "d": "Node-positive (stage III) colon cancer → adjuvant chemotherapy (e.g., oxaliplatin-based); radiation is for rectal cancer", "t": "Treatment ladder — stage III colon cancer = surgery + adjuvant chemo; radiation belongs to rectal cancer", "f": "Node-positive colon cancer = adjuvant chemo; neoadjuvant radiation = rectal cancer", "r": "Stage III (node-positive) colon cancer → resection + adjuvant chemotherapy", "x": [["A) Observation alone with surveillance", "A: Observation is appropriate for low-risk stage I/II disease, not node-positive (stage III) colon cancer."], ["C) Neoadjuvant chemoradiotherapy followed by surgery", "C: Neoadjuvant chemoradiotherapy is used for locally advanced RECTAL cancer, not for colon primaries."], ["D) Palliative chemotherapy", "D: Palliative chemotherapy is for metastatic disease; this patient is M0."]]}, {"n": 40, "s": "A 1-year-old boy has an undescended right testis that has not spontaneously descended. What is the most important long-term concern and management?", "o": [["A", "No cancer risk; observe until adulthood"], ["B", "Immediate orchiectomy"], ["C", "Increased testicular cancer risk + infertility; orchiopexy before puberty"], ["D", "Hormone therapy cures the cancer risk"]], "c": ["C)", "Increased testicular cancer risk + infertility; orchiopexy before puberty"], "co": "Cryptorchidism — infertility + cancer risk; orchiopexy (not orchiectomy)", "ct": "Interpretation", "w": "Cryptorchidism (undescended testis) carries an increased risk of infertility (impaired spermatogenesis from heat) and of germ-cell tumour development in the undescended testis. Management is orchiopexy (surgical fixation) ideally before puberty to preserve function and allow surveillance — not orchiectomy in a child. Hormonal therapy does not eliminate the cancer risk.", "d": "Undescended testis = infertility + germ-cell cancer risk; fix with orchiopexy (not orchiectomy)", "t": "Treatment misdirection — observe/orchiectomy vs orchiopexy before puberty", "f": "Cryptorchidism → infertility + cancer risk; orchiopexy before puberty (not observe/orchiectomy)", "r": "Undescended testis = infertility + germ-cell cancer risk; orchiopexy before puberty", "x": [["A) No cancer risk; observe until adulthood", "Observation alone misses the cancer/infertility risk; fixation is needed."], ["B) Immediate orchiectomy", "Orchiectomy is not indicated in childhood cryptorchidism."], ["D) Hormone therapy cures the cancer risk", "Hormones do not remove the malignant potential."]]}, {"n": 41, "s": "A 66-year-old man is found on routine screening duplex ultrasonography to have a 75% asymptomatic right internal carotid artery stenosis. He has no history of transient ischaemic attacks or stroke, is an ex-smoker, and has well-controlled hypertension. He remains free of neurological symptoms. What is the most appropriate management?", "o": [["A", "Urgent carotid endarterectomy within 2 weeks"], ["B", "Aggressive medical therapy with regular surveillance"], ["C", "Carotid angioplasty with stenting"], ["D", "Immediate anticoagulation with warfarin"]], "c": ["B)", "Aggressive medical therapy with regular surveillance"], "co": "Asymptomatic carotid stenosis — evidence does not support routine intervention; intensive medical therapy (antiplatelet, statin, blood-pressure control, smoking cessation) with surveillance is standard; CEA within 2 weeks is the rule for symptomatic high-grade stenosis.", "ct": "Interpretation — applying the guideline that separates asymptomatic (medical first) from symptomatic (early CEA) carotid stenosis", "w": "This is an asymptomatic 75% carotid stenosis. With modern medical therapy (antiplatelet, statin, blood-pressure control) the annual stroke risk is low, and routine carotid endarterectomy or stenting in asymptomatic patients has not been shown to confer a net benefit; surveillance plus medical therapy is the standard approach. The 'CEA within 2 weeks' rule is explicitly for symptomatic high-grade (70–99%) stenoses, where periprocedural risk is outweighed by the high early stroke risk.", "d": "The stenosis is asymptomatic — found on screening, no TIAs or stroke; the 2-week endarterectomy rule applies only to symptomatic high-grade stenosis, so medical therapy with surveillance is correct here.", "t": "Guideline Version — applying the symptomatic carotid stenosis rule (CEA within 2 weeks) to an asymptomatic patient", "f": "Symptomatic high-grade stenosis (TIA/stroke ipsilateral, <6 months) → CEA within 2 weeks. Asymptomatic stenosis, even 70–99%, → aggressive medical therapy first; intervention is individualized and rarely routine.", "r": "Asymptomatic carotid stenosis → aggressive medical therapy + surveillance; CEA within 2 weeks is reserved for symptomatic high-grade stenosis.", "x": [["A) Urgent carotid endarterectomy within 2 weeks", "Urgent CEA within 2 weeks is the mandate for symptomatic 70–99% stenosis; this patient has no ipsilateral symptoms, so the urgency and indication do not apply."], ["C) Carotid angioplasty with stenting", "Stenting is used when CEA is high-risk or technically difficult and requires individualisation; it is not the routine choice for an asymptomatic stenosis."], ["D) Immediate anticoagulation with warfarin", "Warfarin has no role in carotid territory disease — antiplatelet therapy (aspirin/clopidogrel) is the antithrombotic of choice, and anticoagulation increases haemorrhagic risk without benefit."]]}, {"n": 42, "s": "During total parathyroidectomy for tertiary hyperparathyroidism, the surgeon implants parathyroid tissue into the forearm muscle. What is the purpose?", "o": [["A", "Treat thyroid disease"], ["B", "Mark the recurrent laryngeal nerve"], ["C", "Preserve parathyroid function and allow future access if needed"], ["D", "Prevent chyle leak"]], "c": ["C)", "Preserve parathyroid function and allow future access if needed"], "co": "Parathyroid autotransplantation — preserves function; forearm site allows re-exploration", "ct": "Interpretation", "w": "In total/subtotal parathyroidectomy (e.g., tertiary HPT, MEN), viable parathyroid tissue is autotransplanted, often into the forearm sternocleidomastoid or brachioradialis, to preserve calcium homeostasis and — being superficial — allow easy re-exploration if graft-dependent hyperparathyroidism recurs. It does not address thyroid disease or nerve/chyle issues.", "d": "Autotransplant parathyroid into forearm = preserve function + accessible if graft hyperfunctions", "t": "Treatment ladder — autotransplant parathyroid (forearm) to preserve function + easy access", "f": "Total parathyroidectomy → autotransplant into forearm (preserve function, accessible if recurrence)", "r": "Parathyroid autotransplant (forearm): preserves function; superficial site allows re-exploration if recurrent", "x": [["A) Treat thyroid disease", "It preserves parathyroid, not thyroid, function."], ["B) Mark the recurrent laryngeal nerve", "It does not mark or protect the RLN."], ["D) Prevent chyle leak", "Chyle leak is unrelated to parathyroid autotransplantation."]]}, {"n": 43, "s": "A 30-year-old man presents with dysuria, fever, and perineal pain; the prostate is tender and boggy on exam. What is the most appropriate initial antibiotic?", "o": [["A", "Oral amoxicillin alone"], ["B", "Topical antifungal"], ["C", "Intravenous acyclovir"], ["D", "Fluoroquinolone (e.g., ciprofloxacin)"]], "c": ["D)", "Fluoroquinolone (e.g., ciprofloxacin)"], "co": "Acute bacterial prostatitis — fluoroquinolone, systemic symptoms", "ct": "Interpretation", "w": "Acute bacterial prostatitis presents with dysuria, fever, perineal pain, and a tender, boggy prostate. It requires antibiotics with good prostatic penetration — fluoroquinolones (or TMP-SMX if sensitive) for 2-4 weeks. It is distinct from chronic prostatitis (pelvic pain without systemic signs). Antifungals/antivirals are not indicated.", "d": "Acute prostatitis (fever + perineal pain + tender prostate) = fluoroquinolone (cover Gram-negatives)", "t": "Treatment ladder — fluoroquinolone (prostate penetration) vs inadequate agents", "f": "Acute prostatitis = fluoroquinolone (Gram-negative cover, tissue penetration)", "r": "Acute bacterial prostatitis: fluoroquinolone (good prostatic penetration); fever + tender prostate", "x": [["A) Oral amoxicillin alone", "Amoxicillin alone may not cover the typical Gram-negative organisms or penetrate prostate."], ["B) Topical antifungal", "This is bacterial, not fungal."], ["C) Intravenous acyclovir", "Acyclovir is for viral (herpes), not bacterial prostatitis."]]}, {"n": 44, "s": "After total thyroidectomy for a 3 cm follicular variant papillary carcinoma with extrathyroidal extension, which adjuvant therapy is indicated?", "o": [["A", "External beam radiotherapy"], ["B", "Chemotherapy"], ["C", "No further treatment"], ["D", "Radioiodine (RAI) ablation of residual tissue"]], "c": ["D)", "Radioiodine (RAI) ablation of residual tissue"], "co": "Differentiated thyroid Ca — adjuvant radioiodine after thyroidectomy", "ct": "Interpretation", "w": "Following total thyroidectomy, radioiodine (I-131) ablation is given for intermediate/high-risk differentiated thyroid cancer (tumour >1-4 cm, extrathyroidal extension, nodal metastases) to destroy residual thyroid tissue and facilitate thyroglobulin surveillance. It is not used for low-risk microcarcinomas. Levothyroxine (TSH suppression) is continued. Chemotherapy and external RT are not routine.", "d": "Post-thyroidectomy for higher-risk differentiated Ca (size/extension) → RAI ablation", "t": "Treatment ladder — RAI ablation after thyroidectomy for higher-risk differentiated Ca", "f": "Differentiated thyroid Ca (size/extension/nodes) → total thyroidectomy + adjuvant radioiodine", "r": "Adjuvant RAI after thyroidectomy for intermediate/high-risk differentiated thyroid Ca (size/ETE/nodes)", "x": [["A) External beam radiotherapy", "External beam RT is reserved for unresectable or anaplastic disease."], ["B) Chemotherapy", "Chemotherapy is not used for differentiated thyroid cancer."], ["C) No further treatment", "Higher-risk features here warrant RAI, not observation."]]}, {"n": 45, "s": "A 70-year-old woman with a urinary catheter develops fever, rigors, and hypotension with a lactate of 3.2 mmol/L. What is the most appropriate immediate management?", "o": [["A", "Oral antibiotics and observe"], ["B", "Catheter removal only"], ["C", "Intravenous antibiotics + vasopressors for septic shock"], ["D", "Fluids alone without antibiotics"]], "c": ["C)", "Intravenous antibiotics + vasopressors for septic shock"], "co": "Urosepsis — source of septic shock; antibiotics + vasopressors", "ct": "Analysis/synthesis", "w": "Urosepsis is a common source of sepsis. When hypotension persists despite fluids with lactate >2 mmol/L, septic shock is present and requires prompt intravenous antibiotics (covering Gram-negatives, e.g., broad-spectrum beta-lactam) and vasopressors (noradrenaline) plus source control (catheter change/drainage). Delaying antibiotics/vasopressors worsens outcome.", "d": "Urosepsis with hypotension + lactate >2 = septic shock → antibiotics + vasopressors (fluids + source control)", "t": "Severity under-recognition — urosepsis as septic shock source; need vasopressors not just fluids", "f": "Urosepsis + hypotension + lactate>2 = septic shock → antibiotics + vasopressors + source control", "r": "Urosepsis causing septic shock: antibiotics + vasopressors (noradrenaline) + source control", "x": [["A) Oral antibiotics and observe", "Oral antibiotics and observation are unsafe in septic shock."], ["B) Catheter removal only", "Catheter removal alone does not treat shock."], ["D) Fluids alone without antibiotics", "Fluids alone without antibiotics/vasopressors fail in septic shock."]]}, {"n": 46, "s": "During thyroid lobectomy, the surgeon must ligate the inferior thyroid artery. Why is careful dissection at this site critical for parathyroid preservation?", "o": [["A", "It supplies the recurrent laryngeal nerve directly"], ["B", "It is the only blood supply to the thyroid"], ["C", "It carries parathyroid venous drainage"], ["D", "The inferior thyroid artery supplies the inferior parathyroids; ligate laterally to preserve them"]], "c": ["D)", "The inferior thyroid artery supplies the inferior parathyroids; ligate laterally to preserve them"], "co": "Inferior thyroid artery — supplies inferior parathyroids; ligate laterally to preserve them", "ct": "Interpretation", "w": "The inferior thyroid artery (branch of the thyrocervical trunk) sends vessels to the inferior parathyroid glands. To preserve parathyroid viability during thyroid surgery, the artery should be ligated laterally (away from the gland) so that its parathyroid branches remain patent; skeletonising too close devascularises the parathyroids, causing hypoparathyroidism. This surgical-anatomy point underpins post-thyroidectomy calcium management.", "d": "Inferior thyroid artery gives branches to inferior parathyroids; ligate distal/lateral to avoid devascularising them", "t": "One-word discriminator — inferior thyroid artery supplies inferior parathyroids (ligate lateral)", "f": "Inferior thyroid artery → inferior parathyroids; ligate laterally to preserve them (avoid hypoCa)", "r": "Inferior thyroid artery supplies inferior parathyroids; ligate laterally to preserve parathyroid viability", "x": [["A) It supplies the recurrent laryngeal nerve directly", "The artery does not supply the RLN; the nerve lies in relation to it but is neural, not perfused by it."], ["B) It is the only blood supply to the thyroid", "The superior thyroid artery also supplies the thyroid; the inferior is not sole."], ["C) It carries parathyroid venous drainage", "It is an arterial supply, not venous drainage, to the parathyroids."]]}, {"n": 47, "s": "A 25-year-old man with a T6 spinal cord injury has recurrent urinary tract infections and incomplete emptying. Which management is most appropriate?", "o": [["A", "Indwelling urethral catheter permanently"], ["B", "Fluid restriction only"], ["C", "Anticholinergic to cause retention"], ["D", "Clean intermittent self-catheterization"]], "c": ["D)", "Clean intermittent self-catheterization"], "co": "Neurogenic bladder — intermittent catheterization to protect upper tracts", "ct": "Interpretation", "w": "Neurogenic bladder from spinal cord injury causes incomplete emptying and high pressures that threaten the upper tracts. Clean intermittent self-catheterization (CISC) empties the bladder, reduces infection, and preserves renal function. Indwelling catheters increase infection and stones; anticholinergics without drainage worsen retention.", "d": "Spinal cord injury neurogenic bladder = clean intermittent catheterization (protects kidneys)", "t": "Treatment ladder — intermittent catheterization (kidney protection) vs indwelling", "f": "SCI neurogenic bladder = clean intermittent self-catheterization (not permanent indwelling)", "r": "Neurogenic bladder (SCI): clean intermittent catheterization protects upper tracts; avoid permanent indwelling", "x": [["A) Indwelling urethral catheter permanently", "Permanent indwelling catheters raise infection and stone risk; CISC is preferred."], ["B) Fluid restriction only", "Fluid restriction does not correct incomplete emptying."], ["C) Anticholinergic to cause retention", "Anticholinergics without drainage worsen retention and pressures."]]}, {"n": 48, "s": "A 45-year-old with a 3 cm aldosterone-producing adrenal adenoma and refractory hypertension is planned for surgery. What is the preferred approach?", "o": [["A", "Open laparotomy routinely"], ["B", "Partial nephrectomy"], ["C", "Percutaneous ablation"], ["D", "Laparoscopic adrenalectomy (after medical optimisation)"]], "c": ["D)", "Laparoscopic adrenalectomy (after medical optimisation)"], "co": "Adrenalectomy — laparoscopic approach for Conn/pheo/Ca after optimisation", "ct": "Interpretation", "w": "Most benign adrenal tumours (aldosterone-producing adenoma, phaeochromocytoma, cortisol-producing adenoma) are removed by laparoscopic adrenalectomy, which is less morbid than open surgery. For Conn syndrome, unilateral adenoma resection is curative of the hypertension source; for phaeochromocytoma, alpha-blockade MUST precede surgery. Partial nephrectomy and ablation are not standard.", "d": "Benign adrenal tumours (Conn, pheo, cortisol) → laparoscopic adrenalectomy (minimally invasive)", "t": "Treatment ladder — laparoscopic adrenalectomy for Conn/pheo/cortisol tumours (optimise first)", "f": "Conn/pheo/cortisol adrenal tumour → laparoscopic adrenalectomy (alpha-block first if pheo)", "r": "Adrenal tumour (Conn/pheo/cortisol): laparoscopic adrenalectomy; alpha-block first if phaeochromocytoma", "x": [["A) Open laparotomy routinely", "Open laparotomy is reserved for large/malignant/invasive lesions, not routine benign tumours."], ["B) Partial nephrectomy", "Partial nephrectomy is for renal, not adrenal, pathology."], ["C) Percutaneous ablation", "Percutaneous ablation is not standard for functional adrenal adenomas."]]}, {"n": 49, "s": "A 64-year-old woman had a curative (R0) resection of a pT3 N0 M0 adenocarcinoma of the sigmoid colon 6 months ago. Which of the following is the most appropriate postoperative surveillance plan?", "o": [["A", "Serum CEA every 3–6 months for 2–3 years plus colonoscopy at 1 year"], ["B", "PET-CT every 6 months for life"], ["C", "Annual serum alpha-fetoprotein with liver ultrasound"], ["D", "Symptom-based surveillance only"]], "c": ["A)", "Serum CEA every 3–6 months for 2–3 years plus colonoscopy at 1 year"], "co": "Colorectal carcinoma — postoperative surveillance (CEA + colonoscopy)", "ct": "Recall (post-resection surveillance schedule)", "w": "After curative resection of colon cancer, surveillance comprises serial CEA measurement and colonoscopy at 1 year (then at 3–5 yearly intervals), detecting recurrence and metachronous lesions.", "d": "Curative resection → serial CEA + colonoscopy at 1 year; PET-CT is not routine surveillance", "t": "Investigation hierarchy — CEA + colonoscopy are the surveillance tools; PET-CT is reserved for suspected recurrence", "f": "Post-op surveillance = CEA + colonoscopy at 1 year; AFP is for hepatocellular cancer", "r": "Curative CRC → CEA 3–6 monthly + colonoscopy at 1 year", "x": [["B) PET-CT every 6 months for life", "B: PET-CT is not a first-line surveillance tool; it characterises suspected recurrence."], ["C) Annual serum alpha-fetoprotein with liver ultrasound", "C: Alpha-fetoprotein monitors hepatocellular carcinoma and germ cell tumours, not colorectal cancer."], ["D) Symptom-based surveillance only", "D: Symptom-based surveillance alone misses early, still-treatable recurrence."]]}, {"n": 50, "s": "During a hysterectomy, the ureter is most commonly injured at which anatomical relationship?", "o": [["A", "At the renal hilum"], ["B", "At the ureterovesical junction only"], ["C", "Where it crosses under the uterine artery ('water under the bridge')"], ["D", "In the posterior abdominal wall lateral to psoas"]], "c": ["C)", "Where it crosses under the uterine artery ('water under the bridge')"], "co": "Iatrogenic ureteric injury — at the uterine artery crossing during pelvic surgery", "ct": "Recall", "w": "The ureter runs in the pelvis crossing BELOW (under) the uterine artery — described as 'water under the bridge' — and this distal segment is the most common site of iatrogenic injury during hysterectomy or colorectal surgery. Awareness prevents ligation/clamping. Injury is repaired with ureteroureterostomy or reimplantation depending on level.", "d": "Ureter injury in hysterectomy = at the uterine artery crossing (distal third, 'water under the bridge')", "t": "One-word discriminator — 'water under the bridge' (ureter under uterine artery)", "f": "Hysterectomy ureter injury = at uterine artery crossing (distal third)", "r": "Ureter runs UNDER the uterine artery ('water under the bridge'); distal third = common iatrogenic injury site", "x": [["A) At the renal hilum", "The renal hilum is not the typical site in hysterectomy."], ["B) At the ureterovesical junction only", "The ureterovesical junction is a site but less common than the uterine artery crossing in pelvic surgery."], ["D) In the posterior abdominal wall lateral to psoas", "The psoas/lateral abdominal wall course is retroperitoneal and less often injured in hysterectomy."]]}, {"n": 51, "s": "A 50-year-old man reports a progressively curved, painful erection with a palpable firm band on the dorsal penis. What is the diagnosis?", "o": [["A", "Penile fracture"], ["B", "Priapism"], ["C", "Balanitis"], ["D", "Peyronie disease (fibrous plaque)"]], "c": ["D)", "Peyronie disease (fibrous plaque)"], "co": "Peyronie disease — fibrous plaque causing penile curvature", "ct": "Recall", "w": "Peyronie disease is fibrosis of the tunica albuginea causing a palpable plaque and penile curvature (often painful initially). It is distinct from penile fracture (traumatic tunical rupture with sudden pain and haematoma), priapism (prolonged erection), and balanitis (glans inflammation).", "d": "Palpable fibrous plaque + curvature = Peyronie disease (tunica albuginea fibrosis)", "t": "One-word discriminator — fibrous plaque = Peyronie", "f": "Palpable penile plaque + curvature = Peyronie disease (not fracture/priapism)", "r": "Peyronie = fibrous tunical plaque → curvature; distinct from fracture (trauma) and priapism", "x": [["A) Penile fracture", "Penile fracture is acute trauma with sudden pain and a 'pop', not a chronic plaque."], ["B) Priapism", "Priapism is a sustained painful erection, not curvature with a plaque."], ["C) Balanitis", "Balanitis is inflammation of the glans, not a tunical plaque."]]}, {"n": 52, "s": "A 65-year-old man with severe pneumonia has been mechanically ventilated for 12 days and is expected to require several more weeks of weaning. He is otherwise haemodynamically stable. Which of the following is the most appropriate intervention to facilitate weaning?", "o": [["A", "Tracheostomy"], ["B", "Percutaneous endoscopic gastrostomy"], ["C", "Conversion to non-invasive ventilation"], ["D", "Continued high-dose sedation with daily sedation breaks"]], "c": ["A)", "Tracheostomy"], "co": "Tracheostomy timing — anticipated prolonged ventilation beyond roughly 10–14 days is an indication for tracheostomy, which eases weaning, suctioning, and communication.", "ct": "Recall — applying the tracheostomy threshold for prolonged ventilation", "w": "Tracheostomy is indicated when prolonged mechanical ventilation (beyond about 10–14 days) is anticipated or when repeated extubation fails. Benefits over translaryngeal intubation include easier weaning, more effective suctioning, less ventilator-associated pneumonia, better mouth care, and the ability to communicate. At day 12 with weeks of ventilation expected, tracheostomy is the intervention that facilitates the weaning pathway.", "d": "Ventilated 12 days + several more weeks expected = the tracheostomy window; the other options do not address the prolonged airway requirement.", "t": "Pattern recognition — prolonged ventilation beyond 10-14 days = tracheostomy", "f": "Ventilation expected beyond ~10–14 days, or failed weaning/extubation ×2, or bulbar dysfunction with aspiration → tracheostomy. Early tracheostomy (<4 days) is not routine unless specific indications exist.", "r": "Anticipated ventilation > 10–14 days → tracheostomy to facilitate weaning.", "x": [["B) Percutaneous endoscopic gastrostomy", "PEG is for long-term enteral feeding in swallowing failure — it addresses nutrition, not the need for prolonged airway support and weaning."], ["C) Conversion to non-invasive ventilation", "Non-invasive ventilation cannot replace an endotracheal tube in a patient who is still failing to breathe adequately — the patient is not ready to come off the tube at all."], ["D) Continued high-dose sedation with daily sedation breaks", "Sedation weaning is part of daily practice but does not address the weeks of planned ventilation — the airway itself must be converted to a more manageable form."]]}, {"n": 53, "s": "A patient with Graves disease is prepared for thyroidectomy. In the days before surgery, Lugol's iodine solution is administered. What is its purpose?", "o": [["A", "Ablate the thyroid with radioiodine"], ["B", "Treat the eye disease"], ["C", "Replace thyroid hormone"], ["D", "Reduce thyroid vascularity and hormone release (easier, safer surgery)"]], "c": ["D)", "Reduce thyroid vascularity and hormone release (easier, safer surgery)"], "co": "Pre-thyroidectomy iodine (Lugol) — reduces vascularity/hormone release", "ct": "Interpretation", "w": "Administration of iodine (Lugol's solution or potassium iodide) for 10-14 days before thyroidectomy in Graves disease exploits the Wolff-Chaikoff effect to reduce thyroid blood flow and hormone release, making surgery technically easier and lowering the risk of thyroid storm and bleeding. It is NOT radioiodine ablation, does not treat orbitopathy, and is not hormone replacement. (Beta-blockers control symptoms; antithyroid drugs achieve euthyroidism.)", "d": "Pre-op Lugol iodine in Graves → reduces gland vascularity and hormone leak at surgery", "t": "Treatment misdirection — pre-op Lugol iodine = reduce vascularity (not RAI/thyroxine)", "f": "Graves pre-thyroidectomy: Lugol iodine → reduce gland vascularity + hormone release (safer op)", "r": "Pre-op Lugol iodine in Graves: reduces thyroid vascularity/hormone release for safer thyroidectomy", "x": [["A) Ablate the thyroid with radioiodine", "Radioiodine ablation is a different therapy, not the pre-surgical iodine preparation."], ["B) Treat the eye disease", "Iodine does not treat Graves orbitopathy."], ["C) Replace thyroid hormone", "It is not thyroid hormone replacement."]]}, {"n": 54, "s": "A 45-year-old male presents with progressive right-sided hearing loss, ringing in the right ear, and a feeling of imbalance for 8 months. Otoscopy is normal. Audiometry shows asymmetric sensorineural hearing loss on the right. Which investigation is the gold standard to confirm the diagnosis?", "o": [["A", "Tympanometry"], ["B", "MRI of the internal auditory meatus with gadolinium"], ["C", "CT temporal bone"], ["D", "Electronystagmography"]], "c": ["B)", "MRI of the internal auditory meatus with gadolinium"], "co": "Acoustic neuroma (vestibular schwannoma) — investigation of choice", "ct": "Recall/interpretation", "w": "Progressive asymmetric sensorineural hearing loss with tinnitus in a middle-aged adult raises acoustic neuroma; contrast-enhanced MRI of the internal auditory meatus is the gold standard to detect a CPA mass.", "d": "Asymmetric SNHL + tinnitus in middle age → rule out CPA tumor → MRI with gadolinium is gold standard", "t": "Investigation hierarchy — choosing the wrong imaging modality", "f": "Unilateral SNHL + tinnitus = MRI IAM, always", "r": "Asymmetric SNHL → MRI IAM with gadolinium to exclude vestibular schwannoma", "x": [["A) Tympanometry", "Tympanometry assesses middle ear function and effusion — the middle ear is normal here (otoscopy normal, loss is sensorineural)."], ["C) CT temporal bone", "CT temporal bone is for bony erosion (cholesteatoma, glomus tumor), not for an intracanalicular soft-tissue mass."], ["D) Electronystagmography", "Electronystagmography tests vestibular function but cannot identify or localize a tumor."]]}, {"n": 55, "s": "A 50-year-old factory worker presents with difficulty hearing conversations in noisy settings. Audiometry shows a bilateral sensorineural hearing loss with a characteristic notch at 4000 Hz. What is the most likely cause?", "o": [["A", "Presbycusis"], ["B", "Noise-induced hearing loss"], ["C", "Ototoxic drug exposure"], ["D", "Otosclerosis"]], "c": ["B)", "Noise-induced hearing loss"], "co": "Noise-induced hearing loss — audiometric pattern", "ct": "Interpretation", "w": "The classic 4 kHz notch on audiometry in a worker with occupational noise exposure is diagnostic of noise-induced hearing loss.", "d": "Bilateral SNHL + 4 kHz notch + occupational noise exposure", "t": "Pattern recognition — the 4 kHz notch is the key", "f": "4 kHz notch = noise; ask about occupation", "r": "SNHL with 4 kHz notch + noise exposure = NIHL", "x": [["A) Presbycusis", "Presbycusis is age-related high-frequency loss but typically without a sharp 4 kHz notch."], ["C) Ototoxic drug exposure", "Ototoxic drugs cause bilateral loss but not the characteristic notch pattern."], ["D) Otosclerosis", "Otosclerosis is a conductive hearing loss, not sensorineural."]]}, {"n": 56, "s": "A newborn is noted to have episodes of cyanosis that improve when she cries. A nasogastric tube cannot be passed through the right nostril. What is the most likely diagnosis?", "o": [["A", "Choanal atresia"], ["B", "Nasal foreign body"], ["C", "Antrochoanal polyp"], ["D", "Congenital rhinitis"]], "c": ["A)", "Choanal atresia"], "co": "Choanal atresia — newborn presentation", "ct": "Interpretation", "w": "Cyclical cyanosis relieved by crying (mouth breathing) plus failure to pass a nasogastric tube in a newborn is choanal atresia.", "d": "Cyclical cyanosis relieved by crying + NG tube cannot pass = choanal atresia", "t": "Age-appropriate differential — newborn changes the answer", "f": "Newborn + cannot pass NG tube = choanal atresia", "r": "Newborn cyclical cyanosis + NG tube obstruction = choanal atresia", "x": [["B) Nasal foreign body", "A foreign body is impossible in a newborn."], ["C) Antrochoanal polyp", "Antrochoanal polyp is a child/adolescent lesion, not neonatal."], ["D) Congenital rhinitis", "Congenital rhinitis does not block NG tube passage."]]}, {"n": 57, "s": "A 2-month-old infant has had inspiratory stridor since birth. It is louder when she is supine and during crying, and softer when she is prone. She feeds well and is gaining weight. What is the most likely diagnosis and expected course?", "o": [["A", "Laryngomalacia — resolves spontaneously by 18–24 months"], ["B", "Subglottic stenosis — requires urgent tracheostomy"], ["C", "Vocal cord paralysis — requires immediate intubation"], ["D", "Croup — treat with nebulized adrenaline"]], "c": ["A)", "Laryngomalacia — resolves spontaneously by 18–24 months"], "co": "Laryngomalacia — most common cause of infant stridor", "ct": "Interpretation", "w": "Inspiratory stridor since birth that worsens supine in a thriving infant is laryngomalacia — the most common cause of infant stridor — and resolves spontaneously by 18–24 months.", "d": "Inspiratory stridor since birth + worse supine + thriving infant = laryngomalacia → conservative", "t": "Age-appropriate differential — benign vs surgical stridor", "f": "Stridor since birth + thriving = laryngomalacia, reassure", "r": "Infant stridor since birth + thriving = laryngomalacia → observe", "x": [["B) Subglottic stenosis — requires urgent tracheostomy", "Subglottic stenosis follows intubation and is persistent, not positional."], ["C) Vocal cord paralysis — requires immediate intubation", "Vocal cord paralysis causes a weak cry and feeding difficulty."], ["D) Croup — treat with nebulized adrenaline", "Croup is acute, barking, and affects older infants (6 months–3 years)."]]}, {"n": 58, "s": "A 50-year-old male presents with a slowly enlarging, pulsatile mass at the angle of the jaw, present for 3 years. It moves laterally but not vertically, and a bruit is audible over it. What is the most likely diagnosis?", "o": [["A", "Carotid body tumor"], ["B", "Branchial cyst"], ["C", "Metastatic lymph node"], ["D", "Thyroglossal cyst"]], "c": ["A)", "Carotid body tumor"], "co": "Carotid body tumor (paraganglioma) — neck mass identification", "ct": "Analysis/synthesis", "w": "A slowly enlarging pulsatile neck mass with a bruit that moves laterally but not vertically is a carotid body tumor (chemodectoma at the carotid bifurcation).", "d": "Pulsatile mass + bruit + moves LATERALLY not vertically = carotid body tumor", "t": "Physical sign discrimination — direction of mobility is the key", "f": "Lateral mobility + bruit = carotid body tumor, not thyroid", "r": "Pulsatile mass + bruit + lateral mobility = carotid body tumor", "x": [["B) Branchial cyst", "Branchial cyst is soft, non-pulsatile, and has no bruit."], ["C) Metastatic lymph node", "A metastatic node is hard and fixed."], ["D) Thyroglossal cyst", "Thyroglossal cyst is midline and moves with tongue protrusion."]]}, {"n": 59, "s": "A 33-year-old woman with bipolar I disorder presents with a 3-week episode of major depression while on her mood stabiliser. Which is LEAST appropriate?", "o": [["A", "Add a second mood stabiliser or lamotrigine"], ["B", "Add an atypical antipsychotic such as quetiapine"], ["C", "Use antidepressant monotherapy alone for her depression"], ["D", "Consider ECT for severe depression"]], "c": ["C)", "Use antidepressant monotherapy alone for her depression"], "co": "Bipolar depression — avoid antidepressant MONOTHERAPY (mania switch risk)", "ct": "Analysis/synthesis", "w": "Bipolar depression should be treated with a mood stabiliser and/or an atypical antipsychotic (quetiapine, lurasidone), and lamotrigine is effective. Antidepressant MONOTHERAPY is avoided because it can precipitate a switch into mania or rapid cycling.", "d": "In bipolar depression, antidepressant monotherapy risks triggering mania/hypomania; use mood stabiliser ± atypical antipsychotic", "t": "Treating a bipolar depression with a plain antidepressant the way you would unipolar MDD", "f": "Bipolar depression = mood stabiliser ± atypical antipsychotic ± lamotrigine; avoid antidepressant monotherapy (mania risk)", "r": "For bipolar depression use a mood stabiliser/atypical antipsychotic; do NOT give antidepressant monotherapy due to risk of switching to mania.", "x": [["A) Add a second mood stabiliser or lamotrigine", "adding a mood stabiliser or lamotrigine is appropriate for bipolar depression"], ["B) Add an atypical antipsychotic such as quetiapine", "quetiapine (and lurasidone) are FDA-approved and effective for bipolar depression"], ["D) Consider ECT for severe depression", "ECT is effective and appropriate for severe bipolar depression"]]}, {"n": 60, "s": "A 28-year-old woman with regular 28-day cycles is investigated for infertility. On cycle day 12, ultrasound shows a mature 20 mm dominant follicle and serum estradiol is appropriately elevated, but serial measurements show no mid-cycle LH surge, and follicular rupture never occurs. Which step of the ovarian cycle is failing?", "o": [["A", "The mid-cycle LH surge, which is required to trigger ovulation"], ["B", "FSH-dependent recruitment and growth of the dominant follicle"], ["C", "Progesterone-mediated secretory transformation of the endometrium"], ["D", "Estrogen negative feedback that limits FSH early in the follicular phase"]], "c": ["A)", "The mid-cycle LH surge, which is required to trigger ovulation"], "co": "LH surge — the trigger of ovulation", "ct": "Recall/interpretation (cycle-day timing and hormone roles)", "w": "A mature dominant follicle with rising estradiol proves the follicular phase succeeded. The missing event is the estradiol-triggered mid-cycle LH surge, which induces follicular rupture and oocyte release; without it, ovulation never occurs despite normal follicular maturation.", "d": "Mature follicle + high estradiol but no LH surge = ovulation fails; FSH and estrogen already did their work", "t": "Negative discrimination — falling estrogen and progesterone are consequences of the missed LH surge, not its cause", "f": "No LH surge = no ovulation; anovulation with a good follicle is LH failure, not FSH failure", "r": "Estrogen-positive feedback triggers the LH surge (day 12-14) leading to ovulation; no surge = no ovulation", "x": [["B) FSH-dependent recruitment and growth of the dominant follicle", "FSH-driven follicular recruitment and growth are intact — the follicle reached 20 mm, so FSH completed its role."], ["C) Progesterone-mediated secretory transformation of the endometrium", "Progesterone-driven secretory transformation is a luteal-phase event that happens AFTER ovulation and cannot explain failure to ovulate."], ["D) Estrogen negative feedback that limits FSH early in the follicular phase", "Estrogen negative feedback on FSH is a normal early-follicular mechanism; suppressing FSH is not the missing ovulation trigger."]]}, {"n": 61, "s": "During exercise, muscle capillaries receive deoxygenated blood. Deoxygenated hemoglobin carries more CO2 and H+ than oxygenated hemoglobin, which enhances CO2 removal from working muscle. Which physiological principle does this describe?", "o": [["A", "The Haldane effect"], ["B", "The Bohr effect"], ["C", "The chloride (Hamburger) shift"], ["D", "Temperature-induced dissociation curve shift"]], "c": ["A)", "The Haldane effect"], "co": "Haldane effect — CO2 transport by deoxygenated hemoglobin", "ct": "Interpretation (naming a mechanism from its description)", "w": "The Haldane effect states that deoxygenated hemoglobin binds CO2 (as carbamino compounds) and H+ more readily than oxyhemoglobin, so tissues where oxygen unloads efficiently pick up CO2. It works in partnership with the Bohr effect.", "d": "Enhanced CO2 carriage by DEOXY-hemoglobin = Haldane; altered O2 affinity by CO2/pH = Bohr", "t": "Synonym Swap — Haldane (CO2 carriage) and Bohr (O2 affinity) trade names", "f": "Haldane = deoxy-Hb carries CO2 and H+; Bohr = H+/CO2 lowers O2 affinity; the pair drives tissue CO2 pickup and lung CO2 release", "r": "Deoxygenated Hb carries more CO2 and H+ (Haldane); oxygenation in the lungs releases CO2", "x": [["B) The Bohr effect", "The Bohr effect is how H+ and CO2 lower hemoglobin's affinity for O2 — the oxygen-side partner of the exchange, not the CO2 carriage property."], ["C) The chloride (Hamburger) shift", "The chloride shift moves Cl- into red cells to balance HCO3- leaving them — a CO2 transport step, but not the enhanced carriage by deoxyhemoglobin."], ["D) Temperature-induced dissociation curve shift", "Temperature shifts the O2 dissociation curve during fever or exercise; it does not describe deoxyhemoglobin's CO2 carriage."]]}, {"n": 62, "s": "A preterm infant develops respiratory distress from surfactant deficiency. Which statement correctly applies the LaPlace relationship to explain why the smallest air sacs are most prone to collapse?", "o": [["A", "Collapsing pressure is higher in smaller alveoli (P = 2T/r), so they empty into larger ones unless surfactant uniformly lowers surface tension"], ["B", "Larger alveoli develop higher collapsing pressure and collapse first"], ["C", "Surface tension increases as radius increases, protecting small alveoli"], ["D", "Surfactant raises surface tension to keep small alveoli expanded"]], "c": ["A)", "Collapsing pressure is higher in smaller alveoli (P = 2T/r), so they empty into larger ones unless surfactant uniformly lowers surface tension"], "co": "LaPlace law and surfactant — alveolar stability", "ct": "Interpretation (applied physical principle)", "w": "LaPlace's law (P = 2T/r) makes smaller alveoli generate higher collapsing pressure. Surfactant lowers surface tension — and packs more densely in small alveoli — so tension is equalized and small sacs do not empty into large ones. Deficiency explains the collapse pattern of neonatal respiratory distress.", "d": "P = 2T/r: smaller radius → higher collapsing pressure; surfactant equalizes tension across differently sized alveoli", "t": "Pattern recognition — LaPlace direction: small alveoli, not large ones, are at risk when surfactant fails", "f": "Surfactant lowers T, stabilizes small alveoli, raises compliance and FRC; LaPlace explains why small sacs collapse first", "r": "P = 2T/r; surfactant lowers T and stabilizes small alveoli, preventing collapse into larger ones", "x": [["B) Larger alveoli develop higher collapsing pressure and collapse first", "LaPlace's law places the higher collapsing pressure in SMALLER radii — large alveoli are the more stable units."], ["C) Surface tension increases as radius increases, protecting small alveoli", "Surface tension is a property of the air-liquid interface and does not 'increase with radius' to protect small alveoli."], ["D) Surfactant raises surface tension to keep small alveoli expanded", "Surfactant LOWERS surface tension; raising it would worsen collapse, which is exactly the failure in deficiency."]]}, {"n": 63, "s": "A healthy 28-year-old primigravida at 20 weeks gestation has renal function testing. Compared with her non-pregnant baseline, which renal physiological change is expected?", "o": [["A", "GFR and renal plasma flow rise substantially, partly because afferent arteriolar resistance falls"], ["B", "GFR falls because progesterone constricts the afferent arteriole"], ["C", "GFR is unchanged — the kidney is spared from hormonal changes in pregnancy"], ["D", "GFR rises only during labour and delivery"]], "c": ["A)", "GFR and renal plasma flow rise substantially, partly because afferent arteriolar resistance falls"], "co": "Pregnancy physiology — GFR and renal plasma flow", "ct": "Interpretation (physiological adaptation in pregnancy)", "w": "From early pregnancy, rising cardiac output and falling afferent arteriolar resistance increase renal plasma flow and GFR by roughly 40-50%, which is why serum creatinine normally falls in pregnancy.", "d": "Pregnancy vasodilates the afferent arteriole → renal plasma flow and GFR up ~40-50% from early in the first trimester", "t": "Opposite — pregnancy raises renal plasma flow and GFR; it does not reduce them", "f": "Serum creatinine falls in normal pregnancy; a 'normal' non-pregnant creatinine can already indicate renal compromise", "r": "Pregnancy → afferent vasodilatation → RPF and GFR +40-50% → lower serum creatinine", "x": [["B) GFR falls because progesterone constricts the afferent arteriole", "Progesterone does not constrict the afferent arteriole; pregnancy is a vasodilated, high-GFR state — the opposite direction."], ["C) GFR is unchanged — the kidney is spared from hormonal changes in pregnancy", "The kidney is a major site of pregnancy adaptation; GFR changes are substantial and measurable from the first trimester."], ["D) GFR rises only during labour and delivery", "The rise begins in the first trimester and plateaus by mid-pregnancy; it is not deferred to labour."]]}, {"n": 64, "s": "A 45-year-old woman has fatigue, cold intolerance, and a diffuse goiter. Serum TSH is 38 µIU/mL (markedly elevated) with a low free T4. Which statement best explains this pattern?", "o": [["A", "Loss of T4 negative feedback on the anterior pituitary allows unrestrained TSH secretion"], ["B", "The pituitary is autonomously secreting excess TSH (secondary disease)"], ["C", "TRH is deficient, so TSH accumulates in the blood"], ["D", "TSH-receptor antibodies stimulate TSH secretion"]], "c": ["A)", "Loss of T4 negative feedback on the anterior pituitary allows unrestrained TSH secretion"], "co": "Thyroid-pituitary negative feedback (primary hypothyroidism)", "ct": "Interpretation (hormone pattern → site of lesion)", "w": "In primary hypothyroidism the thyroid fails, free T4 falls, negative feedback on the pituitary thyrotrophs is lost, and TSH rises markedly in compensation — the correct physiological response to a failing gland, not a pituitary tumor.", "d": "Low T4 with HIGH TSH = failing thyroid gland; the pituitary responds appropriately to lost negative feedback", "t": "Pattern recognition — low T4 with high TSH localizes the failure to the thyroid gland, not the pituitary", "f": "High TSH + low T4 = primary hypothyroidism; low TSH + low T4 = secondary (pituitary); high T4 + low TSH = hyperthyroidism", "r": "Primary hypothyroidism = low T4, high TSH (lost negative feedback); secondary = low T4 with low or inappropriately normal TSH", "x": [["B) The pituitary is autonomously secreting excess TSH (secondary disease)", "An autonomous pituitary TSH source (secondary hyperthyroidism) produces HIGH T4 with high or normal TSH — the mirror pattern."], ["C) TRH is deficient, so TSH accumulates in the blood", "TRH deficiency lowers TSH secretion — TSH would be low, not high; TRH stimulates the pituitary, it does not accumulate."], ["D) TSH-receptor antibodies stimulate TSH secretion", "TSH-receptor antibodies (Graves disease) stimulate the thyroid to overproduce hormone — high T4 with low TSH, the opposite pattern."]]}, {"n": 65, "s": "A healthy 68-year-old man fasts for 14 hours before elective surgery. Blood glucose at induction is 88 mg/dL. Which mechanism is the primary source of this glucose during an overnight fast?", "o": [["A", "Hepatic glycogenolysis, with gluconeogenesis rising as glycogen stores deplete"], ["B", "Glycogenolysis in skeletal muscle, which releases glucose into the blood"], ["C", "Direct release of free glucose from adipose tissue lipolysis"], ["D", "Continued glucose absorption from the small intestine"]], "c": ["A)", "Hepatic glycogenolysis, with gluconeogenesis rising as glycogen stores deplete"], "co": "Fuel homeostasis — hepatic glucose output in the fasting state", "ct": "Analysis/synthesis (fuel source identification in fasting)", "w": "The liver possesses glucose-6-phosphatase and exports glucose from glycogen; as glycogen depletes, glucagon-driven gluconeogenesis takes over. Skeletal muscle lacks glucose-6-phosphatase, so muscle glycogen can never raise blood glucose — it is strictly local fuel.", "d": "The liver exports glucose (glucose-6-phosphatase); muscle cannot — its glycogen is trapped for local use", "t": "Negative discrimination — muscle glycogen is muscle fuel and cannot raise blood glucose", "f": "Fasting blood glucose = hepatic output (glycogenolysis then gluconeogenesis); muscle glycogen never enters the bloodstream", "r": "Overnight fast: hepatic glycogenolysis first, gluconeogenesis second; muscle glycogen cannot release free glucose", "x": [["B) Glycogenolysis in skeletal muscle, which releases glucose into the blood", "Muscle lacks glucose-6-phosphatase, so its glycogen cannot be released as blood glucose — the classic liver-versus-muscle distinction."], ["C) Direct release of free glucose from adipose tissue lipolysis", "Lipolysis releases free fatty acids and glycerol; glycerol feeds gluconeogenesis, but no free glucose comes from adipose tissue."], ["D) Continued glucose absorption from the small intestine", "After 14 hours the gut is empty; the glucose must come from endogenous hepatic production, not absorption."]]}, {"n": 66, "s": "During the absolute refractory period of a neuron, a second stimulus of any strength fails to produce an action potential. Which molecular event explains this?", "o": [["A", "Voltage-gated sodium channels are inactivated and cannot reopen until the membrane repolarizes"], ["B", "Sodium channels are closed but available — only the threshold has risen"], ["C", "The sodium-potassium pump is temporarily reversed"], ["D", "Calcium influx dominates the membrane and excludes sodium entry"]], "c": ["A)", "Voltage-gated sodium channels are inactivated and cannot reopen until the membrane repolarizes"], "co": "Action potential — molecular basis of the absolute refractory period", "ct": "Interpretation (channel-state reasoning)", "w": "During the absolute refractory period, voltage-gated sodium channels are in the inactivated state and cannot reopen regardless of stimulus strength until the membrane repolarizes. This enforces one-way conduction and a maximum firing rate.", "d": "Inactivation — not simple closure — makes the absolute period truly absolute; recovery requires repolarization", "t": "Partial Truth — a stronger stimulus overcomes the raised threshold of the RELATIVE period, but cannot beat inactivation", "f": "Absolute = Na+ channels inactivated (no stimulus fires); relative = some channels recovered (stronger stimulus fires)", "r": "Absolute refractory period = Na+ channels inactivated; relative refractory period = recovering channels fire only to stronger stimuli", "x": [["B) Sodium channels are closed but available — only the threshold has risen", "A higher threshold with available channels describes the RELATIVE refractory period, where stronger stimuli do fire — not the absolute period."], ["C) The sodium-potassium pump is temporarily reversed", "The Na+/K+ ATPase maintains gradients continuously and is never reversed; it does not gate excitability."], ["D) Calcium influx dominates the membrane and excludes sodium entry", "Calcium does not dominate the axonal membrane during refractoriness; the story is entirely sodium-channel inactivation."]]}, {"n": 67, "s": "A 30-year-old woman with myasthenia gravis has normal strength at rest, but her grip visibly fatigues with repeated effort. Which electrophysiological mechanism at the neuromuscular junction accounts for this fatigability?", "o": [["A", "End-plate potential amplitude falls progressively with repetitive stimulation, so transmission eventually fails"], ["B", "Voltage-gated sodium channels in the muscle membrane fail after repeated depolarization"], ["C", "The motor nerve exhausts its acetylcholine vesicle supply within seconds"], ["D", "Calcium release from the sarcoplasmic reticulum becomes deficient with fatigue"]], "c": ["A)", "End-plate potential amplitude falls progressively with repetitive stimulation, so transmission eventually fails"], "co": "Neuromuscular junction — decremental transmission in myasthenia gravis", "ct": "Analysis/synthesis (mechanism mapping in a synaptic disorder)", "w": "In myasthenia gravis, autoantibodies destroy postsynaptic ACh receptors, lowering the transmission safety factor. With repeated stimulation, the end-plate potential decrements until it falls below threshold — the classic electrophysiological and clinical fatigability.", "d": "Autoantibody loss of ACh receptors lowers the safety factor — repetitive stimulation produces decremental end-plate potentials until threshold is missed", "t": "Clinical Mimic — the failure sits at the postsynaptic receptor, not in nerve conduction or the muscle fibre", "f": "MG = postsynaptic receptor loss (decremental EPP); Lambert-Eaton = presynaptic calcium-channel failure (incremental response)", "r": "MG: ACh receptor loss → reduced safety factor → decremental end-plate potentials → fatigable weakness", "x": [["B) Voltage-gated sodium channels in the muscle membrane fail after repeated depolarization", "Muscle membrane sodium channels are normal in MG; the deficit is upstream at the ACh receptor."], ["C) The motor nerve exhausts its acetylcholine vesicle supply within seconds", "The nerve's vesicle supply is adequate; the problem is too few effective receptors to capture the released acetylcholine."], ["D) Calcium release from the sarcoplasmic reticulum becomes deficient with fatigue", "SR calcium release underlies excitation-contraction coupling (relevant to myopathies), not the junctional transmission failure of MG."]]}, {"n": 68, "s": "When the patellar tendon is tapped, the quadriceps is stretched and the knee extends. In this reflex, the Ia afferent from the muscle spindle synapses directly (monosynaptically) on which structure to produce the response?", "o": [["A", "The alpha motor neuron supplying the same (quadriceps) muscle"], ["B", "The gamma motor neuron supplying the same muscle spindle"], ["C", "A Renshaw cell inhibitory interneuron"], ["D", "The alpha motor neuron of the antagonist (hamstring) muscle"]], "c": ["A)", "The alpha motor neuron supplying the same (quadriceps) muscle"], "co": "Spinal reflexes — monosynaptic stretch reflex circuitry", "ct": "Recall/interpretation (reflex circuit tracing)", "w": "The muscle-spindle Ia afferent makes a monosynaptic excitatory synapse on the alpha motor neurons of the same (homonymous) muscle, producing the knee jerk. Antagonist inhibition travels through a spinal interneuron, not a direct Ia synapse.", "d": "Ia → homonymous alpha motor neuron, monosynaptic; antagonist inhibition and Renshaw cells sit behind interneurons; gamma neurons tune spindle length", "t": "Synonym Swap — alpha motor neurons execute the reflex; gamma motor neurons tune spindle length", "f": "Ia = spindle → homonymous alpha (knee jerk); gamma = spindle sensitivity; Renshaw cells = recurrent inhibition of the same alpha neuron", "r": "Stretch reflex: Ia afferent → monosynaptic excitation of the homonymous alpha motor neuron; antagonist inhibited via interneuron", "x": [["B) The gamma motor neuron supplying the same muscle spindle", "Gamma motor neurons (fusimotor) regulate spindle sensitivity in parallel; they are not the direct output of the Ia afferent."], ["C) A Renshaw cell inhibitory interneuron", "Renshaw cells mediate recurrent inhibition of the SAME alpha neuron through collaterals — an interneuron-dependent event, not the direct Ia synapse."], ["D) The alpha motor neuron of the antagonist (hamstring) muscle", "A direct Ia synapse on the hamstring alpha neuron would co-contract the antagonist; reciprocal inhibition is routed through an interneuron."]]}, {"n": 69, "s": "A 62-year-old man with paroxysmal supraventricular tachycardia is given intravenous verapamil. Verapamil blocks calcium channels in cardiac muscle and nodal tissue. Which phase of the cardiac action potential is primarily mediated by calcium influx and therefore targeted by verapamil?", "o": [["A", "Phase 0 — rapid sodium influx"], ["B", "Phase 2 — the plateau, sustained by L-type calcium influx"], ["C", "Phase 3 — potassium efflux during repolarization"], ["D", "Phase 4 — the pacemaker sodium funny current"]], "c": ["B)", "Phase 2 — the plateau, sustained by L-type calcium influx"], "co": "Cardiac action potential — ionic basis of the plateau (phase 2)", "ct": "Recall (phase-to-ion mapping)", "w": "Phase 2 is the plateau, during which L-type calcium channels open and Ca2+ influx balances potassium efflux. Verapamil blocks these calcium channels, shortening the plateau and slowing AV nodal conduction.", "d": "Plateau = calcium entry; verapamil, a calcium-channel blocker, must act at the phase calcium mediates", "t": "Synonym Swap — phase-to-ion mapping: sodium owns phase 0, calcium owns phase 2, potassium owns phase 3", "f": "Phase 0 = Na+ (lidocaine), phase 2 = Ca2+ (verapamil), phase 3 = K+ (amiodarone/sotalol), phase 4 = funny current (ivabradine)", "r": "Phase 2 plateau = L-type Ca2+ influx; calcium-channel blockade acts at phase 2", "x": [["A) Phase 0 — rapid sodium influx", "Phase 0 is the rapid sodium upstroke of working myocytes, blocked by class I agents such as lidocaine, not verapamil."], ["C) Phase 3 — potassium efflux during repolarization", "Phase 3 is potassium-mediated repolarization, targeted by class III agents (amiodarone, sotalol) that prolong the plateau and QT interval."], ["D) Phase 4 — the pacemaker sodium funny current", "Phase 4 is the diastolic funny current (If) of pacemaker cells, targeted by ivabradine — it does not mediate the plateau."]]}, {"n": 70, "s": "A 42-year-old woman feels a painless lump in her right breast 3 weeks after a seat-belt injury in a road traffic accident. Mammography shows an ill-defined opacity; biopsy shows lipid-laden macrophages, hemosiderin-laden cells, and fibrous tissue with no atypical epithelial cells. What is the most likely diagnosis?", "o": [["A", "Invasive ductal carcinoma"], ["B", "Fat necrosis"], ["C", "Fibroadenoma"], ["D", "Sclerosing adenosis"]], "c": ["B)", "Fat necrosis"], "co": "Traumatic fat necrosis of the breast — histologic features", "ct": "Interpretation (histology after trauma)", "w": "A lump appearing shortly after trauma with lipid-laden macrophages, hemosiderin, and fibrosis but no epithelial atypia is traumatic fat necrosis — a benign lesion that clinically mimics carcinoma.", "d": "Post-trauma lump + foamy macrophages + hemosiderin + fibrosis with NO atypia = fat necrosis, not carcinoma", "t": "Clinical Mimic — fat necrosis versus breast carcinoma", "f": "Breast lump after trauma = fat necrosis; biopsy proves benign (foamy macrophages, no atypia)", "r": "Fat necrosis = trauma + saponification + foamy macrophages + hemosiderin; no epithelial malignancy", "x": [["A) Invasive ductal carcinoma", "Carcinoma shows malignant epithelial cells with atypia and invasion — the biopsy explicitly shows no atypical epithelial cells."], ["C) Fibroadenoma", "Fibroadenoma is a well-circumscribed fibroepithelial tumor of young women — not a post-traumatic inflammatory process."], ["D) Sclerosing adenosis", "Sclerosing adenosis is a proliferative benign epithelial lesion with distorted glands and fibrosis — no trauma history or foamy macrophages."]]}, {"n": 71, "s": "A 12-year-old boy presents with a 2-week history of fever and a tender swelling in the left armpit. He has several healing scratches on his left forearm from a new kitten. Excision biopsy of the node shows granulomas with central stellate microabscesses. Which organism is the most likely cause?", "o": [["A", "Bartonella henselae"], ["B", "Francisella tularensis"], ["C", "Brucella melitensis"], ["D", "Yersinia enterocolitica"]], "c": ["A)", "Bartonella henselae"], "co": "Cat-scratch disease — Bartonella henselae; stellate microabscesses in granulomas", "ct": "Interpretation (exposure + nodal histology)", "w": "Regional lymphadenopathy after a cat scratch with granulomas containing central stellate microabscesses is cat-scratch disease, caused by the Gram-negative bacillus Bartonella henselae.", "d": "Kitten scratches + regional lymphadenopathy + granulomas with stellate microabscesses = cat-scratch disease (Bartonella henselae)", "t": "Organism homogeneity — all four are zoonotic bacteria", "f": "Cat scratch + regional node + stellate abscesses = Bartonella henselae", "r": "Cat-scratch disease = Bartonella henselae; granulomas with stellate microabscesses; Warthin-Starry silver stain", "x": [["B) Francisella tularensis", "Francisella tularensis (tularemia) follows rabbit or tick exposure, causing ulceroglandular disease — not the kitten-scratch setting."], ["C) Brucella melitensis", "Brucella causes undulant fever after unpasteurized milk or animal contact — not stellate microabscess granulomas in a child's axillary node."], ["D) Yersinia enterocolitica", "Yersinia enterocolitica causes mesenteric adenitis (pseudoappendicitis) — not axillary nodes after a scratch."]]}, {"n": 72, "s": "A 38-year-old man presents with fever, weight loss, testicular pain, and mononeuritis multiplex. Urinalysis shows hematuria and proteinuria. Renal biopsy shows a small artery whose wall is replaced by smudgy, bright pink, granular material with surrounding neutrophils. What is the most likely vascular change?", "o": [["A", "Hyaline arteriolosclerosis"], ["B", "Fibrinoid necrosis"], ["C", "Atherosclerosis"], ["D", "Medial calcific sclerosis"]], "c": ["B)", "Fibrinoid necrosis"], "co": "Fibrinoid necrosis in systemic vasculitis (polyarteritis nodosa)", "ct": "Interpretation (vessel wall morphology + clinical context)", "w": "Bright pink, smudgy, granular material replacing a small-artery wall is fibrinoid necrosis — the characteristic lesion of active vasculitis such as polyarteritis nodosa, a multisystem disease that presents with mononeuritis multiplex.", "d": "Smudgy eosinophilic fibrin-like material destroying a small-artery wall + mononeuritis multiplex + testicular pain = fibrinoid necrosis (polyarteritis nodosa)", "t": "Severity under-recognition — fibrinoid necrosis in active vascular injury", "f": "Smudgy pink vessel wall + multisystem symptoms = fibrinoid necrosis (vasculitis/malignant HTN), not benign hyaline change", "r": "Fibrinoid necrosis = smudgy eosinophilic fibrin deposition destroying vessel walls in active vasculitis or malignant hypertension", "x": [["A) Hyaline arteriolosclerosis", "Hyaline arteriolosclerosis is bland homogeneous pink thickening of arterioles in benign hypertension — no neutrophils or wall destruction."], ["C) Atherosclerosis", "Atherosclerosis affects large and medium arteries with lipid plaques and fibrosis — not the small-artery wall destruction seen here."], ["D) Medial calcific sclerosis", "Medial calcific sclerosis (Monckeberg) is calcification of the media of muscular arteries — without inflammation or fibrin."]]}, {"n": 73, "s": "A 24-year-old man sustains a closed fracture of the femoral shaft in a motorcycle accident and undergoes intramedullary nailing. About 48 hours later he becomes acutely dyspneic and confused, and a petechial rash appears over his chest and axillae. Oxygen saturation is 84% on room air. What is the most likely mechanism?", "o": [["A", "Fat embolism syndrome"], ["B", "Massive pulmonary thromboembolism from a deep vein thrombosis"], ["C", "Air embolism through the intravenous line"], ["D", "Amniotic fluid embolism"]], "c": ["A)", "Fat embolism syndrome"], "co": "Fat embolism syndrome — post-fracture triad of hypoxia, petechiae, and confusion", "ct": "Analysis/synthesis (timing + clinical triad)", "w": "Dyspnea, confusion, and a petechial rash appearing 24–72 hours after a long-bone fracture are the classic triad of fat embolism syndrome: marrow fat enters the circulation and embolizes pulmonary and cerebral microvasculature.", "d": "Long-bone fracture + 24–72 hours + hypoxia + petechiae + confusion = fat embolism syndrome", "t": "What NOT to do — do not anticoagulate fat embolism like thromboembolic PE", "f": "Fracture + 48 h + petechiae + hypoxia = fat embolism (supportive care, not heparin)", "r": "FES = long-bone fracture + hypoxia + petechiae + confusion; management is supportive (oxygen, early fracture fixation)", "x": [["B) Massive pulmonary thromboembolism from a deep vein thrombosis", "Thromboembolism from DVT gives pleuritic chest pain and is not tightly linked to a fresh fracture, and it lacks the petechial rash of FES."], ["C) Air embolism through the intravenous line", "Air embolism causes sudden collapse during line insertion or removal — not delayed rash and confusion after fracture fixation."], ["D) Amniotic fluid embolism", "Amniotic fluid embolism occurs during labor or the immediate postpartum period — not in a male orthopedic patient."]]}, {"n": 74, "s": "A 60-year-old man with worsening heart failure develops a right-sided pleural effusion. Thoracentesis yields clear, straw-colored fluid: total protein 1.9 g/dL, LDH 80 U/L, specific gravity 1.009, and very few cells. What is the most likely mechanism of this fluid accumulation?", "o": [["A", "Increased capillary permeability from inflammation"], ["B", "Increased hydrostatic pressure"], ["C", "Decreased plasma oncotic pressure"], ["D", "Lymphatic obstruction by tumor"]], "c": ["B)", "Increased hydrostatic pressure"], "co": "Transudate vs exudate — mechanism of a transudative effusion", "ct": "Interpretation (fluid analysis → mechanism)", "w": "The fluid is a transudate (protein below 2.5 g/dL, low LDH, low specific gravity, scant cells). In heart failure it accumulates because increased hydrostatic pressure in the veins drives protein-poor fluid into the pleural space.", "d": "Low protein (<2.5 g/dL) + low LDH + low specific gravity + few cells = transudate → heart failure → increased hydrostatic pressure", "t": "Unit/Number — transudate protein below 2.5 g/dL with low LDH", "f": "Protein <2.5 + LDH low = transudate (hydrostatic/oncotic); protein >3 + LDH high = exudate (permeability/lymphatic)", "r": "Transudate (heart failure) = increased hydrostatic pressure; exudate = increased permeability or lymphatic obstruction", "x": [["A) Increased capillary permeability from inflammation", "Increased capillary permeability produces an EXUDATE — high protein and LDH with cells, as in infection or malignancy."], ["C) Decreased plasma oncotic pressure", "Low oncotic pressure (nephrotic syndrome, cirrhosis) also gives a transudate, but the context here is heart failure — hydrostatic pressure is the operative mechanism."], ["D) Lymphatic obstruction by tumor", "Lymphatic obstruction (malignancy) gives an exudative, often chylous or blood-stained fluid with high protein."]]}, {"n": 75, "s": "A 4-year-old boy has had recurrent pneumonia, suppurative lymphadenitis, and a liver abscess. Cultures grow catalase-positive organisms, including Staphylococcus aureus and Serratia marcescens. On the nitroblue tetrazolium (NBT) test, the neutrophils fail to turn blue. What is the most likely diagnosis?", "o": [["A", "Chronic granulomatous disease"], ["B", "Severe combined immunodeficiency"], ["C", "X-linked agammaglobulinemia"], ["D", "Common variable immunodeficiency"]], "c": ["A)", "Chronic granulomatous disease"], "co": "Chronic granulomatous disease — defective respiratory burst; NBT test", "ct": "Analysis/synthesis (recurrent catalase-positive infections + failed NBT)", "w": "Recurrent infections with catalase-positive organisms and NBT-negative neutrophils indicate chronic granulomatous disease — a phagocyte defect of the NADPH oxidase respiratory burst.", "d": "Recurrent catalase-positive infections + NBT neutrophils that FAIL to reduce the dye = chronic granulomatous disease (NADPH oxidase defect)", "t": "Negative discrimination — the positive diagnosis is a failed (negative) test", "f": "Catalase-positive organisms + no NBT color change = chronic granulomatous disease", "r": "CGD = NADPH oxidase failure → catalase-positive infections; NBT/dihydrorhodamine test shows no respiratory burst", "x": [["B) Severe combined immunodeficiency", "SCID presents in infancy with failure to thrive and infections of ALL classes (bacterial, viral, fungal) — not selectively catalase-positive bacteria with a failing NBT test."], ["C) X-linked agammaglobulinemia", "X-linked agammaglobulinemia causes sinopulmonary infections after 6 months with absent B cells and low immunoglobulins — not deep abscesses from catalase-positive organisms."], ["D) Common variable immunodeficiency", "CVID is a later-onset antibody deficiency with low immunoglobulins — the NBT test would be normal."]]}, {"n": 76, "s": "A 45-year-old man presents with 1 week of high fever and right upper quadrant pain. He had an episode of bloody diarrhea 2 months ago. Ultrasound shows a single large abscess in the right lobe of the liver. Aspiration yields thick, reddish-brown ('anchovy sauce') pus. What is the most appropriate initial management?", "o": [["A", "Percutaneous catheter drainage alone"], ["B", "Metronidazole"], ["C", "Urgent surgical deroofing"], ["D", "Radiological embolization"]], "c": ["B)", "Metronidazole"], "co": "Amebic liver abscess — medical treatment of choice", "ct": "Analysis/synthesis (diagnosis → management)", "w": "A single right-lobe abscess with anchovy-sauce pus after amebic dysentery is an amebic liver abscess; uncomplicated cases are treated medically with metronidazole, with drainage reserved for failure or impending rupture.", "d": "Anchovy-sauce pus + prior bloody diarrhea + single right-lobe abscess = amebic abscess → metronidazole (drainage reserved for complications)", "t": "Treatment misdirection — operating on an amebic abscess", "f": "Anchovy-sauce pus + right lobe + diarrhea history = amebic → metronidazole first", "r": "Amebic abscess = metronidazole; pyogenic abscess = antibiotics + drainage", "x": [["A) Percutaneous catheter drainage alone", "Drainage alone is not the primary treatment of an uncomplicated amebic abscess — medical therapy is first-line."], ["C) Urgent surgical deroofing", "Surgical deroofing is reserved for complicated amebic abscesses (rupture, failure of medical therapy), not initial management."], ["D) Radiological embolization", "Embolization has no role in amebic liver abscess."]]}, {"n": 77, "s": "A 30-year-old man presents with a 2-month history of evening fever, night sweats, and a painless left-sided neck swelling. Excision shows matted lymph nodes; on cut section, soft, yellowish-white material with a cheesy consistency oozes from the surface. What type of necrosis is most likely present?", "o": [["A", "Coagulative necrosis"], ["B", "Liquefactive necrosis"], ["C", "Caseous necrosis"], ["D", "Fat necrosis"]], "c": ["C)", "Caseous necrosis"], "co": "Caseous necrosis — gross morphology of tuberculous lymphadenitis", "ct": "Recall (gross morphology recognition)", "w": "Soft, cheesy, yellowish-white material on the cut surface of matted lymph nodes with fever and night sweats is the classic gross appearance of caseous necrosis, the hallmark of tuberculous lymphadenitis.", "d": "Matted cervical nodes + constitutional symptoms + cheesy yellowish-white material = caseous necrosis (tuberculosis)", "t": "Opposite — caseous necrosis (no ghost outlines) vs coagulative (ghost outlines preserved)", "f": "Cheesy necrotic material = caseous = tuberculous until proven otherwise", "r": "Cheesy amorphous necrosis without ghost architecture = caseous (TB); coagulative necrosis keeps ghost outlines", "x": [["A) Coagulative necrosis", "Coagulative necrosis preserves the outline of dead cells (ghost outlines), as in infarction — not the featureless cheesy debris of caseation."], ["B) Liquefactive necrosis", "Liquefactive necrosis forms pus or cysts from neutrophil digestion — this is dry, cheesy material without pus."], ["D) Fat necrosis", "Fat necrosis appears chalky white with saponification and follows pancreatitis or breast trauma — not matted neck nodes."]]}, {"n": 78, "s": "A 3-year-old child with Down syndrome presents with pallor, bruising, and hepatosplenomegaly. Complete blood count shows thrombocytopenia and circulating blasts with cytoplasmic blebs. Which type of leukemia is characteristically associated with Down syndrome in early childhood?", "o": [["A", "Acute megakaryoblastic leukemia"], ["B", "Chronic myeloid leukemia"], ["C", "Hairy cell leukemia"], ["D", "Adult T-cell leukemia/lymphoma"]], "c": ["A)", "Acute megakaryoblastic leukemia"], "co": "Down syndrome — increased risk of acute megakaryoblastic leukemia (GATA1)", "ct": "Interpretation (syndrome-specific leukemia association)", "w": "Children with Down syndrome have a markedly increased risk of acute megakaryoblastic leukemia, often with GATA1 mutations — blasts with cytoplasmic blebs point to megakaryocytic lineage.", "d": "Down syndrome + blasts with cytoplasmic blebs + thrombocytopenia = acute megakaryoblastic leukemia (GATA1 mutations)", "t": "Age-appropriate differential — the ALL reflex in any child with leukemia", "f": "Down syndrome + myeloid/megakaryoblastic leukemia = AMKL (GATA1), not the usual ALL", "r": "Down syndrome → 10–20× leukemia risk, characteristically AMKL with GATA1 mutation in young children", "x": [["B) Chronic myeloid leukemia", "CML is a disease of adults with BCR-ABL and massive splenomegaly — not the Down-syndrome-associated childhood leukemia."], ["C) Hairy cell leukemia", "Hairy cell leukemia affects adults, with tartrate-resistant acid phosphatase-positive hairy lymphocytes — no Down association."], ["D) Adult T-cell leukemia/lymphoma", "Adult T-cell leukemia/lymphoma is caused by HTLV-1 in adults — not associated with Down syndrome."]]}, {"n": 79, "s": "A 55-year-old man is brought in 1 hour after vomiting a large amount of blood. He is anxious and pale, with cool extremities and a heart rate of 118/min. Blood pressure is 115/70 mmHg and urine output is low. What do these findings indicate?", "o": [["A", "Irreversible shock with end-organ failure"], ["B", "Non-progressive (compensated) hypovolemic shock"], ["C", "Septic shock with systemic vasodilation"], ["D", "Cardiogenic shock with pump failure"]], "c": ["B)", "Non-progressive (compensated) hypovolemic shock"], "co": "Shock stages — non-progressive (compensated) shock", "ct": "Analysis/synthesis (vital signs integration)", "w": "Tachycardia, cool pale skin, and oliguria with a still-normal blood pressure indicate compensated (non-progressive) hypovolemic shock: the baroreceptor vasoconstrictor response is maintaining perfusion pressure for now.", "d": "Tachycardia + cool pale extremities + oliguria with a still-normal blood pressure = compensated shock (baroreceptor response still maintains pressure)", "t": "Severity under-recognition — preserved BP hides early shock", "f": "Normal BP + tachycardia + oliguria + cold skin = compensated shock — do not be reassured", "r": "Compensated shock = BP maintained by tachycardia and vasoconstriction; oliguria and cold skin are the early warning signs", "x": [["A) Irreversible shock with end-organ failure", "Irreversible shock shows refractory hypotension with end-organ damage (anuria, altered consciousness) despite resuscitation — blood pressure is still maintained here."], ["C) Septic shock with systemic vasodilation", "Early septic shock is a WARM shock with bounding pulse and vasodilation — this patient is pale and cold."], ["D) Cardiogenic shock with pump failure", "Cardiogenic shock implies pump failure with pulmonary edema and raised filling pressures — the setting here is acute blood loss."]]}, {"n": 80, "s": "A 24-year-old medical student develops malaise, anorexia, and jaundice. Liver biopsy shows scattered single hepatocytes that are shrunken and deeply eosinophilic, with pyknotic nuclei, and no surrounding inflammatory infiltrate. Which term best describes this hepatocyte change?", "o": [["A", "Coagulative necrosis"], ["B", "Mallory hyaline change"], ["C", "Apoptosis (Councilman bodies)"], ["D", "Fatty change"]], "c": ["C)", "Apoptosis (Councilman bodies)"], "co": "Apoptosis — Councilman bodies in viral hepatitis", "ct": "Recall (morphologic definition)", "w": "Shrunken, deeply eosinophilic single hepatocytes with pyknotic nuclei and no surrounding inflammation are Councilman (apoptotic) bodies — the classic morphologic expression of apoptosis in acute viral hepatitis.", "d": "Scattered single shrunken eosinophilic hepatocytes WITHOUT inflammation = Councilman bodies = apoptosis", "t": "Synonym Swap — Councilman (apoptosis) vs Mallory (alcohol hyaline)", "f": "Single shrunken eosinophilic cell, no inflammation = apoptosis; Mallory bodies occur in alcoholic hepatitis with neutrophils", "r": "Councilman bodies = apoptotic hepatocytes (single cells, eosinophilic, pyknotic, no inflammation)", "x": [["A) Coagulative necrosis", "Coagulative necrosis affects sheets of cells and provokes inflammation — not single scattered hepatocytes."], ["B) Mallory hyaline change", "Mallory hyaline is intracytoplasmic eosinophilic material in ballooned hepatocytes of alcoholic hepatitis, usually with neutrophils."], ["D) Fatty change", "Fatty change shows large cytoplasmic lipid vacuoles pushing the nucleus aside — not shrunken eosinophilic cells."]]}, {"n": 81, "s": "A 47-year-old man is brought in 2 hours after ingesting a large quantity of his wife’s amlodipine tablets. He is hypotensive (78/40 mmHg), bradycardic at 42/min, and confused. The ECG shows sinus bradycardia with a normal QRS duration. Which agent is the specific reversal therapy?", "o": [["A", "IV calcium gluconate"], ["B", "IV sodium bicarbonate"], ["C", "IV flumazenil"], ["D", "IV magnesium sulfate"]], "c": ["A)", "IV calcium gluconate"], "co": "Calcium channel blocker overdose — IV calcium as specific therapy", "ct": "Interpretation (hypotension + bradycardia + normal QRS after a CCB)", "w": "CCB overdose blocks calcium entry into cardiac and vascular smooth muscle, causing hypotension and bradycardia with a normal QRS. IV calcium (gluconate or chloride) is the first-line specific therapy to overcome the blockade.", "d": "Hypotension + bradycardia + NORMAL QRS after amlodipine = CCB toxicity → IV calcium", "t": "Clinical Mimic — CCB overdose masquerading as β-blocker or arrhythmic toxicity", "f": "CCB OD = IV calcium first (high-dose insulin if refractory); glucagon is for β-blockers, not CCBs", "r": "CCB overdose → IV calcium chloride/gluconate first; glucagon serves β-blocker overdose", "x": [["B) IV sodium bicarbonate", "Sodium bicarbonate is for TCA-induced wide-QRS toxicity — the QRS here is normal."], ["C) IV flumazenil", "Flumazenil is a benzodiazepine antagonist and is irrelevant to CCB toxicity."], ["D) IV magnesium sulfate", "Magnesium treats torsades de pointes or deficiency, not calcium channel blockade."]]}, {"n": 82, "s": "A 52-year-old woman on lithium carbonate for bipolar disorder started naproxen for arthritis 10 days ago. She now has vomiting, a coarse tremor, ataxia, and slurred speech. Which of the following best explains her presentation and the appropriate next step?", "o": [["A", "Lithium toxicity from NSAID-induced reduced renal clearance — stop lithium and give IV saline"], ["B", "Lithium toxicity from increased lithium absorption — stop lithium and add a thiazide"], ["C", "Naproxen allergy — give an antihistamine and continue lithium"], ["D", "Lithium therapeutic failure — increase the lithium dose"]], "c": ["A)", "Lithium toxicity from NSAID-induced reduced renal clearance — stop lithium and give IV saline"], "co": "Lithium toxicity — NSAID interaction and management", "ct": "Interpretation (new tremor/ataxia/vomiting after an NSAID is added)", "w": "NSAIDs decrease renal lithium excretion, raising serum lithium into the toxic range. Vomiting, coarse tremor, and ataxia are lithium toxicity; management is stopping lithium and IV normal saline, with hemodialysis for severe cases.", "d": "NSAIDs reduce renal lithium clearance → toxicity (vomiting, coarse tremor, ataxia) → stop lithium + IV saline", "t": "Iatrogenic trap — the newly added NSAID precipitated lithium toxicity", "f": "Lithium + NSAID/ACEi/thiazide = toxicity; check levels, give saline, dialyze for severe neuro signs or very high levels", "r": "New tremor + ataxia on lithium → suspect interaction; NSAIDs raise lithium → stop the drug + IV saline", "x": [["B) Lithium toxicity from increased lithium absorption — stop lithium and add a thiazide", "Thiazides also raise lithium levels — adding one would worsen, not help, the toxicity."], ["C) Naproxen allergy — give an antihistamine and continue lithium", "This is drug toxicity, not an allergic reaction to naproxen."], ["D) Lithium therapeutic failure — increase the lithium dose", "Increasing the lithium dose worsens a life-threatening toxicity."]]}, {"n": 83, "s": "A 75-year-old woman with osteoarthritis who takes aspirin regularly presents with fever, tinnitus, and deep, rapid breathing. Arterial blood gas shows pH 7.48, PaCO2 22 mmHg, and bicarbonate 16 mEq/L; the salicylate level is 55 mg/dL. What is the most important next step in management?", "o": [["A", "IV sodium bicarbonate with potassium supplementation"], ["B", "Oral activated charcoal only"], ["C", "IV phenytoin"], ["D", "Stop aspirin and observe alone"]], "c": ["A)", "IV sodium bicarbonate with potassium supplementation"], "co": "Salicylate poisoning — mixed acid-base picture and urinary alkalinization", "ct": "Interpretation (tinnitus + hyperventilation + mixed respiratory alkalosis/metabolic acidosis on aspirin)", "w": "Tinnitus and hyperventilation in a chronic aspirin user with a mixed respiratory alkalosis–metabolic acidosis is salicylate toxicity. IV sodium bicarbonate alkalinizes the urine, enhancing salicylate excretion and protecting the CNS.", "d": "Tinnitus + hyperpnea + high anion gap acidosis + respiratory alkalosis in an aspirin user = salicylism → alkaline diuresis", "t": "Unit/Number — salicylate level thresholds: alkalinize at this level; dialyze at >100 mg/dL or with CNS signs", "f": "Fever + tinnitus + tachypnea = salicylism; alkaline diuresis; dialysis for severe levels or neuro signs", "r": "Salicylate toxicity → IV NaHCO3 (urinary alkalinization); dialysis for refractory acidosis, very high levels, or CNS signs", "x": [["B) Oral activated charcoal only", "Activated charcoal is an early adjunct; it cannot treat established salicylate toxicity."], ["C) IV phenytoin", "Phenytoin is not indicated in salicylate poisoning."], ["D) Stop aspirin and observe alone", "Stopping aspirin without active elimination is insufficient at a level of 55 mg/dL with acid-base disturbance."]]}, {"n": 84, "s": "A 22-year-old man undergoing emergency surgery with sevoflurane and succinylcholine develops a rapid rise in temperature to 40.2°C, severe generalized muscle rigidity, and tachycardia. End-tidal CO2 rises markedly despite increased ventilation. Which single intervention is most important?", "o": [["A", "IV dantrolene sodium"], ["B", "Ice packs and cold IV fluids alone"], ["C", "Deepening anesthesia with more sevoflurane"], ["D", "IV calcium gluconate"]], "c": ["A)", "IV dantrolene sodium"], "co": "Malignant hyperthermia — dantrolene as the specific treatment", "ct": "Analysis/synthesis (volatile anesthetic + sux + rigidity + hyperthermia + rising ETCO2)", "w": "Exposure to a volatile anesthetic and succinylcholine followed by muscle rigidity, hyperthermia, and rising end-tidal CO2 is malignant hyperthermia. Dantrolene, which blocks calcium release from the sarcoplasmic reticulum, is the specific life-saving treatment, and the trigger agent must be stopped immediately.", "d": "Volatile anesthetic + succinylcholine + rigidity + hyperthermia + rising ETCO2 = malignant hyperthermia → dantrolene + stop trigger", "t": "Treatment misdirection — passive cooling without dantrolene fails; the trigger must be stopped", "f": "Rigidity + hyperthermia + rising ETCO2 on volatile anesthetic/sux = dantrolene NOW and stop the trigger", "r": "Malignant hyperthermia → stop the trigger + IV dantrolene 2.5 mg/kg; cooling is adjunctive", "x": [["B) Ice packs and cold IV fluids alone", "Cooling alone does not treat the underlying hypermetabolism — the patient dies without dantrolene."], ["C) Deepening anesthesia with more sevoflurane", "Continuing the volatile anesthetic worsens the crisis; the trigger must be stopped immediately."], ["D) IV calcium gluconate", "Calcium has no role in MH; dantrolene blocks sarcoplasmic reticulum calcium release."]]}, {"n": 85, "s": "A 29-year-old woman with depression is brought in 90 minutes after ingesting amitriptyline. She is confused and hypotensive, and the ECG shows sinus tachycardia with a QRS duration of 150 ms. What is the most appropriate immediate therapy?", "o": [["A", "IV sodium bicarbonate"], ["B", "IV lidocaine"], ["C", "IV metoprolol"], ["D", "Oral activated charcoal alone"]], "c": ["A)", "IV sodium bicarbonate"], "co": "Tricyclic antidepressant overdose — sodium bicarbonate for QRS widening", "ct": "Analysis/synthesis (wide QRS + hypotension after a TCA)", "w": "TCA overdose blocks myocardial sodium channels, widening the QRS. Sodium bicarbonate provides both sodium and alkalemia, reversing the blockade and preventing ventricular arrhythmias.", "d": "TCA overdose + QRS >140 ms = myocardial sodium-channel blockade → IV sodium bicarbonate (alkalinization) first-line", "t": "Treatment misdirection — antiarrhythmics (lidocaine/β-blockers) are dangerous here; bicarbonate is the antidote", "f": "TCA + wide QRS = IV NaHCO3; lidocaine, amiodarone, and β-blockers worsen the blockade", "r": "TCA poisoning with QRS widening → IV sodium bicarbonate; benzodiazepines for seizures", "x": [["B) IV lidocaine", "Lidocaine adds further sodium-channel blockade and is contraindicated."], ["C) IV metoprolol", "β-blockade worsens hypotension in TCA toxicity."], ["D) Oral activated charcoal alone", "Charcoal is adjunctive and cannot reverse established cardiotoxicity."]]}, {"n": 86, "s": "A 28-year-old woman at 30 weeks of gestation is found to have blood pressure 168/104 mmHg on two occasions. She is otherwise well with no proteinuria. Which antihypertensive is most appropriate, and which class must be avoided?", "o": [["A", "Labetalol — avoid ACE inhibitors"], ["B", "Ramipril — avoid methyldopa"], ["C", "Lisinopril — avoid labetalol"], ["D", "Losartan — avoid nifedipine"]], "c": ["A)", "Labetalol — avoid ACE inhibitors"], "co": "Antihypertensive therapy in pregnancy — drug safety and teratogens", "ct": "Interpretation (safe antihypertensive selection in pregnancy)", "w": "In pregnancy, labetalol, methyldopa, or nifedipine are appropriate first-line antihypertensives, whereas ACE inhibitors and ARBs are teratogenic (oligohydramnios, renal dysgenesis) and must be avoided.", "d": "Pregnancy + hypertension → labetalol/methyldopa/nifedipine are safe; ACE inhibitors and ARBs are teratogenic → avoid", "t": "Negative discrimination — ACE inhibitors and ARBs are the drugs to AVOID in pregnancy, not to dose-adjust", "f": "Pregnancy + hypertension = labetalol/methyldopa/nifedipine; ACE inhibitors and ARBs are never used (fetal renal damage)", "r": "Antihypertensive in pregnancy → labetalol/methyldopa/nifedipine; ACE inhibitors and ARBs contraindicated", "x": [["B) Ramipril — avoid methyldopa", "Ramipril is an ACE inhibitor (teratogenic), and methyldopa is not contraindicated — the pairing is reversed."], ["C) Lisinopril — avoid labetalol", "Lisinopril is teratogenic, while labetalol is safe — the pairing is reversed."], ["D) Losartan — avoid nifedipine", "Losartan is an ARB (teratogenic), while nifedipine is safe — the pairing is reversed."]]}, {"n": 87, "s": "A 61-year-old man with COPD on sustained-release theophylline develops acute bronchitis and is prescribed ciprofloxacin. Three days later he has nausea, palpitations, and a generalized seizure. Which mechanism best explains what happened?", "o": [["A", "Ciprofloxacin inhibits CYP450, raising theophylline levels into the toxic range"], ["B", "Ciprofloxacin induces theophylline metabolism, causing a withdrawal effect"], ["C", "Theophylline inhibits ciprofloxacin elimination, causing fluoroquinolone toxicity"], ["D", "An allergic cross-reaction between the two drugs"]], "c": ["A)", "Ciprofloxacin inhibits CYP450, raising theophylline levels into the toxic range"], "co": "Drug interaction — fluoroquinolone inhibition of theophylline metabolism (CYP1A2)", "ct": "Interpretation (seizure after adding ciprofloxacin to theophylline)", "w": "Ciprofloxacin inhibits CYP1A2, the enzyme that metabolizes theophylline, raising theophylline levels into the toxic range — presenting with nausea, tachycardia, and seizures. Theophylline levels should be monitored and the dose reduced.", "d": "Theophylline + ciprofloxacin → CYP1A2 inhibition → theophylline toxicity (nausea, tachycardia, seizures)", "t": "Opposite — inhibition misread as induction; the direction of the enzyme interaction is the trap", "f": "Ciprofloxacin/levofloxacin + theophylline = check levels; inhibitors RAISE theophylline → seizures", "r": "Ciprofloxacin inhibits CYP1A2 → theophylline levels rise → toxicity; monitor levels and reduce the dose", "x": [["B) Ciprofloxacin induces theophylline metabolism, causing a withdrawal effect", "Ciprofloxacin INHIBITS, not induces, theophylline clearance — levels rise, they do not fall."], ["C) Theophylline inhibits ciprofloxacin elimination, causing fluoroquinolone toxicity", "The toxic drug is theophylline (narrow therapeutic index); this is not fluoroquinolone toxicity."], ["D) An allergic cross-reaction between the two drugs", "This is a pharmacokinetic interaction, not an allergic reaction."]]}, {"n": 88, "s": "A 33-year-old man with treatment-resistant schizophrenia, stable on clozapine for 6 months, presents with sudden high-grade fever and a severe sore throat. His white cell count is 1,800/mm³ with neutrophils 300/mm³. What is the most appropriate next step?", "o": [["A", "Stop clozapine immediately, monitor the FBC, and institute infection precautions"], ["B", "Continue clozapine and treat the sore throat with antibiotics"], ["C", "Reduce the clozapine dose by half and review"], ["D", "Add a second antipsychotic to cover the clozapine gap"]], "c": ["A)", "Stop clozapine immediately, monitor the FBC, and institute infection precautions"], "co": "Clozapine — agranulocytosis and mandatory monitoring", "ct": "Analysis/synthesis (fever + sore throat + severe neutropenia on clozapine)", "w": "Clozapine causes potentially fatal agranulocytosis, most often within the first 6 months. Fever and sore throat with an absolute neutrophil count of 300 require immediate and permanent discontinuation of clozapine, FBC monitoring, and infection precautions.", "d": "Clozapine + fever/sore throat + ANC below 500 = agranulocytosis → STOP clozapine NOW and never restart casually", "t": "Priority inversion — antibiotics for the fever come second; stopping the offending drug comes first", "f": "Clozapine + fever = urgent FBC; agranulocytosis → stop the drug forever + G-CSF/hematology input", "r": "Clozapine agranulocytosis (ANC <500) → stop the drug, reverse isolation, G-CSF, hematology review", "x": [["B) Continue clozapine and treat the sore throat with antibiotics", "Continuing clozapine with severe neutropenia is life-threatening; antibiotics alone do not address the cause."], ["C) Reduce the clozapine dose by half and review", "Dose reduction does not reverse established agranulocytosis — the drug must stop."], ["D) Add a second antipsychotic to cover the clozapine gap", "Antipsychotic coverage is irrelevant in an acute neutropenic crisis."]]}, {"n": 89, "s": "A 14-month-old girl develops a generalised tonic-clonic seizure during a fever of 39.2 C from acute otitis media. The seizure lasts 90 seconds and stops spontaneously; she is drowsy for 15 minutes then fully alert. Neurological examination is normal. Which single feature would mandate a lumbar puncture?", "o": [["A", "Age 14 months"], ["B", "Seizure duration of 90 seconds"], ["C", "Focal seizure features before the generalised phase"], ["D", "Fever of 39.2 C"]], "c": ["C)", "Focal seizure features before the generalised phase"], "co": "Febrile seizures — simple vs complex; indications for lumbar puncture", "ct": "Interpretation (seizure semiology → complex febrile seizure criteria)", "w": "A simple febrile seizure (6 months–5 years, generalised, <15 minutes, one in 24 h, normal exam) needs no LP if well-looking. A focal onset converts it to a complex febrile seizure; meningeal signs, persistent drowsiness, or lack of a clear source are the LP triggers.", "d": "Focal onset or postictal focal neurology makes the seizure complex and raises intracranial infection concern; age <12 months, prolonged >15 min or focal features trigger LP consideration", "t": "Sequence trap — treating the fever as the answer rather than analysing the seizure semiology", "f": "Focal features, >15 min duration, or recurrent seizures within 24 h = complex febrile seizure → evaluate for intracranial infection.", "r": "Complex febrile seizure (focal, prolonged, or recurrent within 24 h) → investigate for meningitis/encephalitis; simple febrile seizure in a well child needs no LP unless meningismus or no identifiable source.", "x": [["A) Age 14 months", "Age alone is not an LP criterion in a well 14-month-old with a clear source and normal exam; <12 months is the usual threshold to consider LP more readily."], ["B) Seizure duration of 90 seconds", "90 seconds is a short, simple febrile seizure; the >15-minute threshold defines prolonged/complex."], ["D) Fever of 39.2 C", "Height of fever does not itself mandate LP; the semiology and examination drive the decision."]]}, {"n": 90, "s": "A 3-year-old boy has had fever for 6 days, bilateral non-exudative conjunctivitis, cracked red lips, strawberry tongue, and an erythematous rash with swelling of the hands and feet. He is irritable and refuses to bear weight. Which is the most appropriate immediate treatment?", "o": [["A", "Oral amoxicillin for 10 days"], ["B", "Intravenous immunoglobulin plus high-dose aspirin"], ["C", "Oral prednisolone alone"], ["D", "Supportive care and observation for 48 more hours"]], "c": ["B)", "Intravenous immunoglobulin plus high-dose aspirin"], "co": "Kawasaki disease — diagnosis and acute treatment", "ct": "Analysis/synthesis (clinical criteria → treatment urgency)", "w": "This meets Kawasaki disease criteria (fever 6 days + conjunctivitis + oral changes + rash + extremity swelling). IVIG 2 g/kg plus high-dose aspirin within 10 days of fever onset reduces coronary artery aneurysm risk; corticosteroids are reserved for IVIG-resistant disease.", "d": "Fever ≥5 days plus four of five mucocutaneous criteria → Kawasaki disease; IVIG within 10 days cuts coronary aneurysm risk significantly", "t": "Missed-diagnosis trap — treating a viral exanthem rather than recognising Kawasaki disease", "f": "Fever ≥5 days + ≥4 of 5 mucocutaneous features (conjunctivitis, oral, rash, extremities, cervical lymphadenopathy) → IVIG + aspirin before day 10.", "r": "Kawasaki disease: IVIG 2 g/kg single dose + high-dose aspirin (80–100 mg/kg/day divided) in the acute phase, then low-dose aspirin after afebrile; echocardiography for coronary aneurysms at 2–6 weeks.", "x": [["A) Oral amoxicillin for 10 days", "Antibiotics play no role; the disease is a vasculitis, not a bacterial infection."], ["C) Oral prednisolone alone", "Corticosteroids are second-line for IVIG-resistant Kawasaki, not first-line acute therapy."], ["D) Supportive care and observation for 48 more hours", "Observation delays definitive therapy and risks coronary aneurysm; the criteria are already met."]]}, {"n": 91, "s": "A 6-week-old infant presents with cough, coryza, and poor feeding for 2 days. Temperature 37.8 C, respiratory rate 62/min, SpO2 91% in room air, and wheeze with fine crackles on auscultation. Which is the most appropriate management?", "o": [["A", "Oral amoxicillin and discharge with advice"], ["B", "Admission with supportive care: nasal suction, feeding support, and oxygen if SpO2 <90%"], ["C", "Inhaled bronchodilators every 4 hours"], ["D", "Systemic corticosteroids for 3 days"]], "c": ["B)", "Admission with supportive care: nasal suction, feeding support, and oxygen if SpO2 <90%"], "co": "Bronchiolitis — admission criteria and supportive management", "ct": "Interpretation (age + oxygen saturation → admission threshold)", "w": "Moderate bronchiolitis (usually RSV) in a 6-week-old: admission is indicated by age <3 months, SpO2 ≤92%, and poor feeding. Care is supportive — nasal suction, small frequent feeds, oxygen when SpO2 <90%. Bronchodilators, steroids, and antibiotics do not change outcomes in typical bronchiolitis.", "d": "Age <12 weeks with SpO2 91% and poor feeding meets admission criteria; management is supportive — no bronchodilators, steroids, or antibiotics routinely", "t": "Treatment reflex trap — trying asthma-style bronchodilators/steroids for viral bronchiolitis", "f": "Bronchiolitis: age <3 months, SpO2 ≤92%, poor feeding, or apnoea → admit; supportive care only, oxygen if SpO2 <90%.", "r": "Bronchiolitis management is supportive (suction, hydration, oxygen); no routine bronchodilators/steroids/antibiotics; admission for age <3 months, SpO2 ≤92%, poor feeding, or apnoea.", "x": [["A) Oral amoxicillin and discharge with advice", "Antibiotics are not indicated; bronchiolitis is viral and antibiotics do not alter the course unless secondary bacterial infection is proven."], ["C) Inhaled bronchodilators every 4 hours", "Bronchodilators give no sustained benefit in acute viral bronchiolitis and are not routine."], ["D) Systemic corticosteroids for 3 days", "Corticosteroids are ineffective in bronchiolitis and are not recommended routinely."]]}, {"n": 92, "s": "A 9-month-old exclusively breastfed infant presents with pallor and irritability. Hb 8.1 g/dL, MCV 68 fL, low serum ferritin, and normal WBC and platelet counts. At what age should iron supplementation have been started to prevent this deficiency?", "o": [["A", "Birth"], ["B", "4–6 months"], ["C", "12 months"], ["D", "Only after weaning is complete at 18 months"]], "c": ["B)", "4–6 months"], "co": "Iron deficiency anaemia in infants — prevention and supplementation timing", "ct": "Recall (prevention timing)", "w": "Exclusively breastfed term infants deplete maternal iron stores by approximately 4–6 months; complementary iron-rich foods or supplementation is recommended from 4–6 months, especially for breastfed infants. Preterm infants need supplementation earlier (from 2–4 weeks) as their stores are smaller.", "d": "Breast milk iron stores are adequate for about 4–6 months; exclusive breastfeeding beyond this without iron carries risk of deficiency", "t": "Timing trap — assuming exclusive breast milk covers iron needs indefinitely past 6 months", "f": "Iron supplementation for exclusively breastfed term infants from 4–6 months; preterm infants from 2–4 weeks.", "r": "Term breastfed infants: iron supplementation or iron-rich complementary food from 4–6 months; preterm/low-birth-weight infants: 2–4 mg/kg/day elemental iron from 2–4 weeks of age.", "x": [["A) Birth", "Term infants are born with sufficient iron stores; universal supplementation at birth is unnecessary."], ["C) 12 months", "Starting at 12 months is too late — deficiency and developmental effects may already be established."], ["D) Only after weaning is complete at 18 months", "Delaying until 18 months leaves the infant iron-deficient during a critical neurodevelopmental window."]]}, {"n": 93, "s": "A 2-year-old boy has bowing of the legs, widened wrists, and a rachitic rosary. Serum calcium is low-normal, phosphate is low, and alkaline phosphatase is markedly elevated. Which deficiency is most likely and what is the first-line treatment?", "o": [["A", "Vitamin D deficiency; oral vitamin D supplementation"], ["B", "Calcium deficiency; IV calcium infusion"], ["C", "Vitamin C deficiency; ascorbic acid replacement"], ["D", "Phosphorus deficiency; phosphate supplements"]], "c": ["A)", "Vitamin D deficiency; oral vitamin D supplementation"], "co": "Nutritional rickets — diagnosis and treatment", "ct": "Interpretation (biochemistry pattern → deficiency)", "w": "Nutritional rickets from vitamin D deficiency classically shows low/normal calcium, low phosphate, and high ALP with bowing, widened metaphyses (wrist), and rachitic rosary. First-line is oral vitamin D with adequate dietary calcium; biochemical response is monitored after 2–4 weeks.", "d": "Low phosphate + high ALP with clinical rickets = vitamin D deficiency; response to oral vitamin D is first-line", "t": "Cause confusion trap — attributing rickets to calcium alone rather than vitamin D as the primary driver", "f": "Rickets pattern: bowing + wide wrists + low phosphate + high ALP → vitamin D deficiency → oral vitamin D + calcium.", "r": "Rickets: confirm with low phosphate and high ALP (plus low/normal calcium and low 25-OHD); treat with oral vitamin D and ensure calcium intake; recheck in 2–4 weeks.", "x": [["B) Calcium deficiency; IV calcium infusion", "Calcium alone without vitamin D does not correct the underlying deficiency; IV calcium is only for symptomatic hypocalcaemia."], ["C) Vitamin C deficiency; ascorbic acid replacement", "Scurvy causes perifollicular haemorrhage and gingival swelling, not bowing with a rachitic rosary."], ["D) Phosphorus deficiency; phosphate supplements", "Phosphate supplements are not first-line; the condition is driven by vitamin D deficiency, not primary phosphate lack."]]}, {"n": 94, "s": "A 3-week-old infant has poor feeding and prolonged jaundice. Newborn screening TSH is 85 mIU/L (normal <10). Which statement about this infant's condition is correct?", "o": [["A", "The jaundice will resolve without treatment by 8 weeks"], ["B", "Immediate thyroxine replacement prevents intellectual disability"], ["C", "This is physiological jaundice and needs no follow-up"], ["D", "Surgery is required to correct the defect"]], "c": ["B)", "Immediate thyroxine replacement prevents intellectual disability"], "co": "Congenital hypothyroidism — screening and treatment window", "ct": "Interpretation (screening result → urgency)", "w": "Newborn screening detects congenital hypothyroidism (incidence ~1:3,000) via elevated TSH. Prompt thyroxine replacement (before 2 weeks, ideally within the first 10 days) prevents irreversible intellectual disability and growth failure. Prolonged jaundice with poor feeding is a classic presentation in the affected infant.", "d": "Elevated screening TSH = congenital hypothyroidism; thyroxine started early protects neurodevelopment", "t": "Delay trap — treating prolonged neonatal jaundice as breast-milk jaundice without checking screening TSH", "f": "Prolonged jaundice + poor feeding + high TSH = congenital hypothyroidism → thyroxine now; start before age 2 weeks.", "r": "Congenital hypothyroidism: screen with TSH/T4; start levothyroxine immediately if TSH elevated; target normal TSH/free T4 within 2–4 weeks; poor neurodevelopment is preventable with early treatment.", "x": [["A) The jaundice will resolve without treatment by 8 weeks", "This is pathological, not physiological; jaundice from hypothyroidism does not resolve spontaneously by 8 weeks while the deficiency persists."], ["C) This is physiological jaundice and needs no follow-up", "TSH of 85 mIU/L is diagnostic, not physiological; untreated it causes permanent neurodevelopmental damage."], ["D) Surgery is required to correct the defect", "No surgery exists for congenital hypothyroidism; lifelong thyroxine is the treatment."]]}, {"n": 95, "s": "A 15-month-old girl is brought with her first documented urinary tract infection: fever 39 C, vomiting, and E. coli on culture. Which investigation is recommended after this first febrile UTI?", "o": [["A", "Renal biopsy"], ["B", "Renal and bladder ultrasound (within 6 weeks)"], ["C", "Cystoscopy"], ["D", "No imaging is needed after a single UTI"]], "c": ["B)", "Renal and bladder ultrasound (within 6 weeks)"], "co": "UTI in children — imaging after first febrile infection", "ct": "Recall (investigation strategy)", "w": "After a first febrile UTI in a young child, renal and bladder ultrasound is recommended (ideally within 6 weeks of the infection) to look for structural anomalies such as hydronephrosis, obstruction, or renal scarring risk factors. DMSA scans assess scarring; VCUG is considered when ultrasound is abnormal or for recurrent febrile infections, particularly in younger infants.", "d": "First febrile UTI in an infant/young child warrants renal and bladder ultrasound to detect structural abnormality; DMSA/VCUG are used selectively", "t": "Overtesting trap — jumping to VCUG/DMSA for every first infection versus selective use based on ultrasound", "f": "Febrile UTI in a child → renal-bladder ultrasound within 6 weeks; VCUG if abnormal ultrasound, atypical organism, or recurrent infection.", "r": "First febrile UTI in children: renal and bladder ultrasound within 6 weeks; further imaging (DMSA, VCUG) is guided by ultrasound findings, atypical features, or recurrence.", "x": [["A) Renal biopsy", "Biopsy is not part of routine UTI imaging and is reserved for specific parenchymal disease."], ["C) Cystoscopy", "Cystoscopy is not indicated for first UTI; it is used for specific structural/surgical problems."], ["D) No imaging is needed after a single UTI", "Imaging IS recommended after the first febrile UTI in a young child because structural anomalies are detectable and treatable."]]}, {"n": 96, "s": "A 4-day-old term neonate develops bilious vomiting and failure to pass meconium. Abdominal radiograph shows dilated bowel loops with few air-fluid levels. The most likely diagnosis is:", "o": [["A", "Pyloric stenosis"], ["B", "Intestinal obstruction from malrotation with volvulus"], ["C", "Necrotising enterocolitis"], ["D", "Meconium ileus without cystic fibrosis"]], "c": ["B)", "Intestinal obstruction from malrotation with volvulus"], "co": "Neonatal intestinal obstruction — bilious vomiting", "ct": "Analysis/synthesis (bilious vomiting + no meconium → malrotation/volvulus)", "w": "Bilious vomiting with failure to pass meconium in the first days of life is malrotation with volvulus until proven otherwise — a surgical emergency because midgut ischaemia develops within hours. Pyloric stenosis presents at 3–6 weeks with non-bilious projectile vomiting. NEC is typically in preterm infants with abdominal distension and blood in stool.", "d": "Bilious vomiting in a neonate is a surgical emergency until proven otherwise: malrotation with midgut volvulus is the classic cause", "t": "Time-critical trap — treating bilious vomiting as feeding reflux instead of recognising a surgical abdomen", "f": "Bilious vomiting in a neonate = malrotation/volvulus until excluded; request urgent upper GI contrast study and surgical referral.", "r": "Neonatal bilious vomiting = intestinal obstruction until proven otherwise (malrotation/volvulus); urgent surgical evaluation; do not delay with 'wait and see' feeding trials.", "x": [["A) Pyloric stenosis", "Pyloric stenosis presents at 3–6 weeks with non-bilious projectile vomiting and an olive-shaped mass; it does not cause bilious vomiting at day 4."], ["C) Necrotising enterocolitis", "NEC mainly affects preterm infants with abdominal distension, bloody stools, and pneumatosis on x-ray; not the first-line diagnosis in a term 4-day-old with bilious vomiting."], ["D) Meconium ileus without cystic fibrosis", "Meconium ileus typically presents with failure to pass meconium and distension but is strongly associated with cystic fibrosis and fits less with bilious vomiting as the lead feature."]]}, {"n": 97, "s": "A 5-year-old presents with abrupt onset of headache, fever, vomiting, and neck stiffness. A petechial rash appears on the trunk within hours. What is the single most urgent initial action?", "o": [["A", "Lumbar puncture before any antibiotic"], ["B", "IV antibiotics immediately (after blood culture), then LP if stable"], ["C", "CT scan of head before any other step"], ["D", "Oral antibiotics and review in 6 hours"]], "c": ["B)", "IV antibiotics immediately (after blood culture), then LP if stable"], "co": "Meningococcal septicaemia — urgent management", "ct": "Analysis/synthesis (clinical urgency prioritisation)", "w": "Fever, headache, neck stiffness, and a rapidly appearing petechial rash are meningococcal septicaemia until proven otherwise. IV antibiotics (third-generation cephalosporin) must be given immediately after a blood culture, without delaying for LP or CT — early treatment reduces mortality. LP can follow once the child is stabilised and after excluding raised ICP.", "d": "Petechial/purpuric rash + fever + meningism = meningococcal disease; antibiotics must not be delayed for LP or CT", "t": "Wasted-time trap — prioritising LP/CT over antibiotics in a life-threatening presentation", "f": "Fever + rash + meningism = give IV antibiotics now; LP and imaging come after stabilisation.", "r": "Suspected meningococcal disease: IV ceftriaxone immediately after blood culture (do not wait for LP/CT); notify public health; treat close contacts with prophylaxis.", "x": [["A) Lumbar puncture before any antibiotic", "Waiting for LP delays life-saving antibiotics and is unsafe if raised intracranial pressure is present; do LP after stabilisation."], ["C) CT scan of head before any other step", "CT is not required before antibiotics in classic meningococcal presentation and causes unacceptable delay."], ["D) Oral antibiotics and review in 6 hours", "Oral antibiotics and delayed review are dangerous in a rapidly progressive septicaemic illness."]]}, {"n": 98, "s": "An 8-year-old boy has a 3-week history of worsening pain and limping, worse at night, with no trauma. Examination reveals restricted hip movement. He is otherwise afebrile. Which is the most important next investigation?", "o": [["A", "Plain radiograph of the hip followed by MRI if normal or suspicious"], ["B", "Ultrasound-guided hip aspiration immediately"], ["C", "Bone scan only"], ["D", "Observe for 2 more weeks before imaging"]], "c": ["A)", "Plain radiograph of the hip followed by MRI if normal or suspicious"], "co": "Hip pathology in children — Perthes vs septic arthritis", "ct": "Interpretation (gradual pain + limp with restricted movement → imaging strategy)", "w": "Persistent night pain with a limp and restricted hip movement — especially in a school-aged child — must exclude serious pathology: Perthes disease, osteomyelitis, Ewing sarcoma, or a bone tumour. Plain radiograph is the first step; MRI is essential when radiographs are normal or suspicious because it detects early avascular necrosis, infection, and marrow lesions missed on plain film. The afebrile course makes septic arthritis less likely but does not remove the urgency.", "d": "Night pain, limp, restricted movement, afebrile — an ominous presentation that must exclude malignancy/osteomyelitis; MRI is the sensitive confirmatory test", "t": "'It's just a strain' trap — reassuring a child with night pain and restricted movement without imaging", "f": "Night pain + limp + restricted hip motion = image now; if radiograph normal, MRI — do not 'wait and watch'.", "r": "A child with night pain and restricted movement needs urgent imaging: radiograph first, MRI for normal/suspicious films; malignancy and Perthes must be actively excluded.", "x": [["B) Ultrasound-guided hip aspiration immediately", "Aspiration is indicated for suspected septic arthritis (fever, acute painful hip, raised inflammatory markers); the afebrile gradual course makes it less likely as the first step."], ["C) Bone scan only", "Bone scan has largely been replaced by MRI, which gives better anatomical detail and staging."], ["D) Observe for 2 more weeks before imaging", "Observation delays diagnosis of potentially serious and time-sensitive pathology such as Perthes or a bone tumour."]]}, {"n": 99, "s": "A 2-day-old infant has repeated episodes of cyanosis that improve with crying. He feeds poorly and has an intermittent 'sandpaper' quality to breathing. Which condition does this suggest and what is the immediate management?", "o": [["A", "Choanal atresia; oropharyngeal airway and urgent ENT referral"], ["B", "Transient tachypnoea of the newborn; supportive oxygen"], ["C", "Congenital diaphragmatic hernia; immediate intubation"], ["D", "Laryngomalacia; reassurance only"]], "c": ["A)", "Choanal atresia; oropharyngeal airway and urgent ENT referral"], "co": "Bilateral choanal atresia — paradoxical cyanosis", "ct": "Analysis/synthesis (cyanosis relieved by crying → nasal obstruction)", "w": "Paradoxical (cyclic) cyanosis relieved by crying is classic for bilateral choanal atresia — the newborn cannot breathe through the nose. Immediate management is an oral airway (or intubation) to bypass obstruction, with urgent ENT referral for definitive repair. This is a life-threatening airway emergency at birth.", "d": "Cyanosis that improves with crying suggests nasal obstruction: neonates are obligate nose breathers; bilateral choanal atresia is the paradigm", "t": "Pattern recognition trap — missing the 'cyanosis improves with crying' clue that localises obstruction to the nose", "f": "Cyclic cyanosis relieved by crying = choanal atresia; place an oral airway and get ENT now; also check for CHARGE association.", "r": "Bilateral choanal atresia: oral airway/intubation to bypass nasal obstruction, urgent ENT referral; assess for associated anomalies (CHARGE).", "x": [["B) Transient tachypnoea of the newborn; supportive oxygen", "TTN is self-limiting with tachypnoea after birth and clears in 24–48 h; it does not produce cyanosis relieved by crying."], ["C) Congenital diaphragmatic hernia; immediate intubation", "CDH presents with respiratory distress and scaphoid abdomen at birth, not with cyanosis relieved by crying."], ["D) Laryngomalacia; reassurance only", "Laryngomalacia gives inspiratory stridor from the first weeks of life, not cyclical cyanosis in a 2-day-old."]]}, {"n": 100, "s": "A 12-year-old girl has palatal petechiae, an itchy maculopapular rash, and fatigue. Full blood count shows Hb 9.8 g/dL, platelets 42,000/mcL, and atypical lymphocytes on smear. Which is the most likely diagnosis?", "o": [["A", "Immune thrombocytopenic purpura alone"], ["B", "Infectious mononucleosis (Epstein-Barr virus)"], ["C", "Acute lymphoblastic leukaemia"], ["D", "Aplastic anaemia"]], "c": ["B)", "Infectious mononucleosis (Epstein-Barr virus)"], "co": "Infectious mononucleosis — atypical lymphocytes and thrombocytopenia", "ct": "Interpretation (rash + atypical lymphocytosis + thrombocytopenia)", "w": "Fever, fatigue, palatal petechiae, lymphadenopathy, atypical lymphocytes, and mild thrombocytopenia are classic infectious mononucleosis (EBV) — the rash becomes prominent if amoxicillin is given. Ebstein-Barr causes a reactive atypical lymphocytosis; platelet counts drop mildly-to-moderately in about half of cases. ALL and aplastic anaemia produce more severe pancytopenia with lymphoblasts, not atypical reactive lymphocytes.", "d": "Palatal petechiae + itchy rash + atypical lymphocytes in an adolescent = EBV mononucleosis; thrombocytopenia is a recognised feature", "t": "Look-alike trap — confusing reactive atypical lymphocytes with leukaemic blasts", "f": "Adolescent + fever + palatal petechiae + atypical lymphocytosis = EBV; get heterophile antibody/EBV serology, not a bone marrow.", "r": "Infectious mononucleosis: fever, sore throat, lymphadenopathy, atypical lymphocytosis; heterophile antibody confirms; supportive care; avoid amoxicillin due to rash; splenic rupture precautions with contact sports for 3–4 weeks.", "x": [["A) Immune thrombocytopenic purpura alone", "ITP would explain isolated thrombocytopenia but not the atypical lymphocytes, palatal petechiae with rash, or fatigue pattern."], ["C) Acute lymphoblastic leukaemia", "ALL shows cytopenias with circulating blasts and is progressive; the reactive lymphocyte picture and self-limited pattern point away from leukaemia."], ["D) Aplastic anaemia", "Aplastic anaemia gives severe pancytopenia and marrow failure, not an atypical lymphocytosis with a viral syndrome."]]}, {"n": 101, "s": "A 6-year-old with known type 1 diabetes presents with vomiting, abdominal pain, and deep sighing respiration. Blood glucose 480 mg/dL, capillary ketones high, pH 7.15. In addition to IV fluids, what is the correct insulin regimen?", "o": [["A", "IV insulin infusion at 0.05–0.1 units/kg/hour, started after fluid resuscitation"], ["B", "Subcutaneous rapid-acting insulin bolus every 2 hours"], ["C", "IV insulin bolus of 0.3 units/kg immediately"], ["D", "Wait for potassium results before starting insulin"]], "c": ["A)", "IV insulin infusion at 0.05–0.1 units/kg/hour, started after fluid resuscitation"], "co": "Diabetic ketoacidosis — insulin therapy", "ct": "Recall (DKA protocol detail)", "w": "DKA management: IV fluids first (10–20 mL/kg over 1 hour), then continuous IV insulin at 0.05–0.1 units/kg/hour. Insulin should not be given as a bolus in children. Potassium must be checked/withheld appropriately before starting insulin because insulin drives potassium intracellularly and can precipitate hypokalaemia. In adolescence, cerebral oedema is the feared complication, so fluids and glucose adjustment are monitored closely.", "d": "DKA: IV insulin infusion 0.05–0.1 units/kg/h AFTER initial fluid resuscitation; bolus not recommended; potassium check before insulin", "t": "Protocol-order trap — reversing the sequence: fluids before insulin, potassium checked alongside", "f": "DKA child: fluids first (cautious, watch for cerebral oedema), then insulin infusion at 0.05–0.1 U/kg/h; check potassium before insulin.", "r": "DKA: resuscitate with isotonic fluid, then IV insulin infusion 0.05–0.1 units/kg/h; add dextrose when glucose falls below ~250–300 mg/dL; monitor potassium and glucose hourly; watch for cerebral oedema.", "x": [["B) Subcutaneous rapid-acting insulin bolus every 2 hours", "SC rapid-acting boluses are not the standard in DKA; continuous IV infusion gives smoother correction and easier titration."], ["C) IV insulin bolus of 0.3 units/kg immediately", "An IV insulin bolus is not recommended in paediatric DKA because it increases the risk of osmotic shifts and cerebral oedema."], ["D) Wait for potassium results before starting insulin", "Insulin is not withheld waiting for potassium — potassium is checked and corrected alongside because insulin itself alters potassium balance."]]}, {"n": 102, "s": "A 4-year-old has cramps, carpopedal spasm, and is found to have a positive Trousseau sign. Serum calcium 6.2 mg/dL, magnesium 1.2 mg/dL, phosphate 4.8 mg/dL. Which is the most correct initial step?", "o": [["A", "IV calcium gluconate alone"], ["B", "Check and correct magnesium"], ["C", "Oral calcium supplements only"], ["D", "Parathyroid hormone assay before any treatment"]], "c": ["B)", "Check and correct magnesium"], "co": "Hypocalcaemia — magnesium co-deficiency", "ct": "Interpretation (hypocalcaemia with hypomagnesaemia → treat the magnesium)", "w": "Symptomatic hypocalcaemia with carpopedal spasm needs prompt treatment, but associated hypomagnesaemia (Mg <1.5 mg/dL) impairs parathyroid hormone release and makes calcium replacement ineffective. Magnesium must be measured and corrected alongside calcium. IV calcium gluconate is appropriate for acute tetany, but correcting magnesium is essential for a durable response.", "d": "Hypocalcaemia refractory to calcium replacement is frequently due to coexisting hypomagnesaemia; both must be corrected", "t": "Partial-treatment trap — correcting calcium while ignoring the magnesium that perpetuates the hypocalcaemia", "f": "Hypocalcaemia that does not correct = check magnesium; hypomagnesaemia blocks PTH — replace Mg first or together.", "r": "Symptomatic hypocalcaemia: IV calcium gluconate for tetany/seizures, but always check magnesium; if hypomagnesaemia (Mg <1.5 mg/dL), give magnesium sulphate — calcium replacement alone will fail.", "x": [["A) IV calcium gluconate alone", "IV calcium alone treats the immediate symptom but fails if hypomagnesaemia persists, which suppresses PTH release."], ["C) Oral calcium supplements only", "Oral calcium is too slow for active carpopedal spasm — this is an acute symptomatic presentation needing IV therapy."], ["D) Parathyroid hormone assay before any treatment", "PTH assay is part of the workup but must not delay emergent correction of calcium and magnesium."]]}, {"n": 103, "s": "A 28-year-old primigravida at 39 weeks presents with painful, regular uterine contractions every 3 minutes. On vaginal examination the cervix is 6 cm dilated, 90% effaced, membranes intact. What is this phase of labour called and what is the expected cervical dilatation rate in a primigravida?", "o": [["A", "Latent phase; about 0.5 cm/hour"], ["B", "Active phase; at least 1 cm/hour"], ["C", "Second stage; 2 cm per contraction"], ["D", "Transition phase; no fixed rate"]], "c": ["B)", "Active phase; at least 1 cm/hour"], "co": "Stages and phases of labour — active phase dilatation", "ct": "Recall (labour curve norms)", "w": "Active labour begins when the cervix reaches approximately 6 cm with regular painful contractions. The expected active-phase dilatation is at least 1 cm/hour in a primigravida (often faster). The latent phase (before 6 cm) is slower and more variable. This stage runs until full dilatation (10 cm), after which the second stage begins.", "d": "Cervix ≥6 cm with regular contractions = active phase; primigravida active-phase rate is ~1 cm/hour or more", "t": "Definition trap — confusing latent with active phase at the 6 cm threshold", "f": "Active phase = ≥6 cm dilated + regular contractions; primigravida rate ≥1 cm/hour; slower progress is the trigger to assess for dystocia.", "r": "First stage: latent (up to ~6 cm, variable duration) then active (≥6 cm) at ≥1 cm/hour in primigravidas; second stage = full dilatation to delivery; abnormalities of progress prompt partogram review.", "x": [["A) Latent phase; about 0.5 cm/hour", "0.5 cm/hour describes the latent phase, not the active phase at 6 cm dilation."], ["C) Second stage; 2 cm per contraction", "Second stage begins only at full dilatation (10 cm); dilatation is not measured per contraction."], ["D) Transition phase; no fixed rate", "The active phase has defined minimum progress norms, so a fixed expected rate does exist (≥1 cm/h in a primigravida)."]]}, {"n": 104, "s": "A 32-year-old G2P1 at 34 weeks has a blood pressure of 155/105 mmHg and 2+ proteinuria on dipstick. She has a headache and epigastric pain. What is the most appropriate immediate management?", "o": [["A", "Oral labetalol and discharge with home monitoring"], ["B", "Admit, start IV antihypertensive, give magnesium sulphate, and deliver after stabilisation"], ["C", "Immediate caesarean section in the emergency department"], ["D", "Methyldopa only, reassess in one week"]], "c": ["B)", "Admit, start IV antihypertensive, give magnesium sulphate, and deliver after stabilisation"], "co": "Severe pre-eclampsia — emergency management", "ct": "Interpretation (BP + proteinuria + symptoms = severe disease → hospital care)", "w": "Severe pre-eclampsia: BP ≥160/110 (or ≥150/105 on repeated readings) with proteinuria plus headache and epigastric pain signals impending eclampsia. Management is admission, IV antihypertensives (labetalol/hydralazine/nifedipine), magnesium sulphate seizure prophylaxis, corticosteroids for fetal lung maturity if <36 weeks, and delivery after maternal stabilisation (within 24–48 hours at this gestation, balancing fetal maturity).", "d": "Headache and epigastric pain indicate severe pre-eclampsia / impending eclampsia; IV antihypertensive + magnesium sulphate + planned stabilised delivery", "t": "Denial trap — treating severe pre-eclampsia as mild outpatient disease despite red-flag symptoms", "f": "Severe pre-eclampsia (BP ≥160/110, headache, epigastric pain, ≥2+ proteinuria) = admit + IV antihypertensive + MgSO4 + steroids; deliver after stabilisation.", "r": "Severe pre-eclampsia: hospitalise; control BP with IV antihypertensive; MgSO4 for eclampsia prophylaxis; betamethasone if <36 weeks; deliver once stabilised — do not manage outpatient.", "x": [["A) Oral labetalol and discharge with home monitoring", "This is severe disease with warning symptoms; outpatient management with oral medication risks eclampsia and maternal complications."], ["C) Immediate caesarean section in the emergency department", "Immediate caesarean before stabilisation and steroid cover increases maternal-fetal risk; stabilise first."], ["D) Methyldopa only, reassess in one week", "Methyldopa is an oral option for chronic/mild hypertension, not first-line for acute severe pre-eclampsia with warning features."]]}, {"n": 105, "s": "A 26-year-old G1P0 at 41+2 weeks is admitted for induction. The Bishop score is 4. Which method is most appropriate for cervical ripening?", "o": [["A", "Prostaglandin E2 (dinoprostone) intravaginally"], ["B", "Oxytocin infusion immediately"], ["C", "Amniotomy alone"], ["D", "Immediate caesarean section"]], "c": ["A)", "Prostaglandin E2 (dinoprostone) intravaginally"], "co": "Induction of labour — cervical ripening with unfavourable cervix", "ct": "Interpretation (Bishop score guides induction method)", "w": "Induction with an unfavourable cervix (Bishop score ≤6) requires ripening first — prostaglandins (PGE1 misoprostol or PGE2 dinoprostone) soften and dilate the cervix. Oxytocin and amniotomy are used once the cervix is favourable (Bishop ≥7). Prostaglandins are contraindicated in labour and after previous caesarean (scar rupture risk).", "d": "Bishop score ≤6 = unfavourable cervix → ripen with prostaglandins before oxytocin/amniotomy", "t": "Sequence trap — starting oxytocin on an unripened cervix, guaranteeing failed induction", "f": "Bishop ≤6 = ripen with prostaglandins first; oxytocin/amniotomy only after the cervix is favourable (≥7).", "r": "Unfavourable cervix (Bishop ≤6): prostaglandins for ripening. Favourable cervix: oxytocin ± amniotomy. Avoid prostaglandins in prior caesarean/scarred uterus (use mechanical methods like Foley catheter).", "x": [["B) Oxytocin infusion immediately", "Oxytocin without ripening increases failed induction and caesarean rates; it requires a favourable cervix."], ["C) Amniotomy alone", "Amniotomy alone is inadequate for an unripened cervix and adds infection risk if delivery is delayed."], ["D) Immediate caesarean section", "Caesarean is not first-line for postdates with an unfavourable cervix; induction with ripening is standard."]]}, {"n": 106, "s": "A 30-year-old G3P2 has a history of two previous caesarean deliveries. She is now in spontaneous labour at 39 weeks with strong contractions and reports sudden severe abdominal pain over the previous scar. The fetal heart shows persistent decelerations. What is the most likely diagnosis?", "o": [["A", "Placental abruption"], ["B", "Uterine rupture"], ["C", "Cord prolapse"], ["D", "Chorioamnionitis"]], "c": ["B)", "Uterine rupture"], "co": "Uterine rupture — scar rupture in labour", "ct": "Analysis/synthesis (scarred uterus + acute pain + fetal distress = rupture)", "w": "Uterine rupture is a catastrophic complication in a scarred uterus — it presents with sudden severe abdominal/scar pain, loss of fetal station, vaginal bleeding, fetal heart deceleration, and maternal shock. With two previous caesareans (higher scar burden) and this picture, immediate caesarean (often hysterotomy repair or hysterectomy) is required. Placental abruption is not scar-localised and usually involves bleeding + hypertonus.", "d": "Previous caesarean + sudden severe scar pain + fetal heart decelerations during labour = uterine rupture until proven otherwise", "t": "Attribution trap — giving the pain a benign diagnosis in a scarred uterus during labour", "f": "Scarred uterus + sudden severe pain + fetal distress = uterine rupture → immediate laparotomy.", "r": "Suspect uterine rupture with: previous caesarean, sudden severe pain over the scar, vaginal bleeding, fetal distress, loss of station; treat with immediate delivery and laparotomy.", "x": [["A) Placental abruption", "Abruption causes acute pain, bleeding, and fetal distress but is not localised to a previous scar and lacks the scar context."], ["C) Cord prolapse", "Cord prolapse follows membrane rupture with presenting part not engaged; it does not cause scar-localised severe pain."], ["D) Chorioamnionitis", "Chorioamnionitis gives fever, uterine tenderness, and fetal tachycardia — not sudden acute scar pain with decelerations."]]}, {"n": 107, "s": "A 25-year-old woman at 8 weeks gestation has vaginal spotting and ultrasound shows an intrauterine gestational sac with a fetal pole but no cardiac activity (crown-rump length 16 mm, no heartbeat). What is the most appropriate diagnosis and plan?", "o": [["A", "Threatened miscarriage; reassure and repeat scan in 2 weeks"], ["B", "Missed (early) miscarriage; discuss expectant, medical, or surgical management"], ["C", "Ectopic pregnancy; give methotrexate"], ["D", "Normal pregnancy; the heart is not yet visible at this size"]], "c": ["B)", "Missed (early) miscarriage; discuss expectant, medical, or surgical management"], "co": "Early pregnancy loss — missed miscarriage diagnosis", "ct": "Interpretation (CRL without cardiac activity = confirmed miscarriage)", "w": "In the first trimester, a crown-rump length of ≥7 mm with absent cardiac activity is diagnostic of miscarriage — as is a gestational sac ≥25 mm without a yolk sac/fetal pole. At CRL 16 mm the heart should be visible, so a missed (early) miscarriage is confirmed. Management options (expectant, medical with misoprostol, or surgical MVA) are discussed with the woman.", "d": "CRL ≥7 mm with no cardiac activity = definite miscarriage; no need to wait for a repeat scan", "t": "False-hope trap — calling a confirmed missed miscarriage 'threatened' because of scant bleeding", "f": "CRL ≥7 mm + no heartbeat = definite miscarriage; CRL <7 mm ± no heart = repeat scan in 7–14 days.", "r": "Definite miscarriage: CRL ≥7 mm without cardiac activity, or sac ≥25 mm without embryo; offer expectant, medical, or surgical management with counselling.", "x": [["A) Threatened miscarriage; reassure and repeat scan in 2 weeks", "Threatened miscarriage is bleeding with a viable pregnancy; a 16 mm fetus without a heartbeat is a confirmed loss, not a threatened one."], ["C) Ectopic pregnancy; give methotrexate", "There is an intrauterine sac, so ectopic pregnancy is excluded; methotrexate would be wrong and dangerous."], ["D) Normal pregnancy; the heart is not yet visible at this size", "Cardiac activity is normally visible from ~6 weeks / CRL 5–7 mm; its absence at 16 mm is not normal."]]}, {"n": 108, "s": "A 34-year-old G2P1 at 38 weeks has an antepartum haemorrhage with painless bright red bleeding, approximately 300 mL. The uterus is soft and non-tender; fetal heart is reassuring. On ultrasound the placenta lies over the internal os. What is the correct immediate plan?", "o": [["A", "Digital vaginal examination to assess the cervix"], ["B", "Ultrasound-guided assessment, avoid vaginal examination, admit, and plan delivery by caesarean"], ["C", "Artificial rupture of membranes"], ["D", "Prostaglandin induction of labour"]], "c": ["B)", "Ultrasound-guided assessment, avoid vaginal examination, admit, and plan delivery by caesarean"], "co": "Placenta praevia — management", "ct": "Interpretation (painless bleeding + placenta over os = praevia)", "w": "Placenta praevia: painless bright-red antepartum bleeding, soft non-tender uterus, placenta covering the internal os. Vaginal examination is contraindicated (precipitates catastrophic haemorrhage). The plan is admission, no digital examination, gentle ultrasound assessment, corticosteroids if <36 weeks, and caesarean delivery (at 36–37 weeks if bleeding, or earlier if massive).", "d": "Painless bright-red bleeding with a soft uterus and placenta over the os = placenta praevia; NEVER do a vaginal examination — 'do not touch'", "t": "Forbidden-action trap — the digital examination that converts praevia into exsanguination", "f": "Painless antepartum bleeding + placenta over os = praevia; no vaginal exams; admit + caesarean delivery.", "r": "Placenta praevia: no digital vaginal examination; admit, ultrasound assessment, steroids if premature, deliver by caesarean at 36–37 weeks (or earlier for uncontrolled bleeding).", "x": [["A) Digital vaginal examination to assess the cervix", "Vaginal examination in praevia can trigger torrential bleeding; it is absolutely contraindicated without controlled theatre conditions."], ["C) Artificial rupture of membranes", "ARM requires vaginal access and is contraindicated in praevia; it also cannot help when the placenta obstructs the lower segment."], ["D) Prostaglandin induction of labour", "Induction of labour is wrong; placental obstruction of the os mandates caesarean, not vaginal delivery."]]}, {"n": 109, "s": "A 40-year-old G4P3 at 32 weeks is diagnosed with gestational diabetes mellitus. Her fasting blood glucose is 135 mg/dL despite 2 weeks of dietary modification. What is the most appropriate next step?", "o": [["A", "Continue diet alone and recheck in 4 weeks"], ["B", "Start oral metformin or insulin per local protocol"], ["C", "Immediate caesarean section at 32 weeks"], ["D", "Increase dietary carbohydrates to prevent ketosis"]], "c": ["B)", "Start oral metformin or insulin per local protocol"], "co": "Gestational diabetes — escalation from diet to therapy", "ct": "Interpretation (failed dietary control → pharmacotherapy)", "w": "GDM targets: fasting <95 mg/dL and 1-hour postprandial <140 mg/dL (or 2-hour <120 per some guidelines). When diet and exercise fail to control glucose, pharmacological therapy is started — metformin (oral) or insulin (first-line in many settings). Continuing diet alone risks macrosomia, polyhydramnios, and fetal hyperinsulinaemia. Delivery is not indicated at 32 weeks for GDM alone.", "d": "Fasting glucose ≥95 mg/dL (or ≥140 postprandial) despite diet = pharmacological therapy; metformin or insulin", "t": "Protocol-lag trap — persisting with failed diet rather than escalating to medication", "f": "GDM: if fasting ≥95 or postprandial above target after 1–2 weeks of diet, start metformin/insulin; do not delay.", "r": "GDM: diet + exercise first; add metformin or insulin when fasting ≥95 mg/dL or postprandial ≥140 (1 h); monitor fetal growth; deliver at term unless complications.", "x": [["A) Continue diet alone and recheck in 4 weeks", "A further 4 weeks of failed diet exposes the fetus to uncontrolled hyperglycaemia and macrosomia; escalation is due now."], ["C) Immediate caesarean section at 32 weeks", "Preterm delivery at 32 weeks is not indicated for uncontrolled GDM; it causes prematurity complications."], ["D) Increase dietary carbohydrates to prevent ketosis", "Increasing carbohydrate worsens postprandial excursions; the GDM diet restricts and distributes carbohydrate intake."]]}, {"n": 110, "s": "A 29-year-old G1P0 at 40 weeks is in the second stage of labour for 45 minutes. The fetal head is at the perineum and crown visible with each contraction. The woman is pushing effectively. What is the appropriate management?", "o": [["A", "Immediate vacuum delivery"], ["B", "Encourage continued pushing with lateral support and reassess progress"], ["C", "Start oxytocin infusion"], ["D", "Arrange emergency caesarean section"]], "c": ["B)", "Encourage continued pushing with lateral support and reassess progress"], "co": "Normal second stage — expectant management with progress", "ct": "Interpretation (active pushing with visible crown = normal progress)", "w": "In a primigravida the second stage may last up to 2–3 hours with regional anaesthesia (1–2 hours without); active pushing with the head crowning is normal progress. Management is continued encouragement, lateral/squatting support, perineal care, fetal monitoring. Instrumental delivery is indicated for prolonged second stage, maternal exhaustion, or fetal compromise — none present here. Oxytocin does not augment the second stage once fully dilated.", "d": "Visible crown with effective maternal effort = progress; allow continued pushing; instrument delivery is for delay/compromise", "t": "Intervention-reflex trap — escalating to vacuum/caesarean during normal progress", "f": "Second stage: allow up to 2–3 h (with epidural) if reassuring; intervene for lack of descent, maternal exhaustion, or fetal distress.", "r": "Second stage with reassuring fetal status and descent: supportive care, position of choice, directed pushing; instrument if no progress after 1–2 h of pushing or fetal compromise.", "x": [["A) Immediate vacuum delivery", "Vacuum is not indicated with active descent and reassuring fetal heart; it carries morbidity when used without indication."], ["C) Start oxytocin infusion", "Oxytocin augments first-stage contractions; in the second stage, pushing effort (not uterine contractions alone) drives descent."], ["D) Arrange emergency caesarean section", "Caesarean is not indicated during normal-progress second stage with crowning; it is reserved for true obstruction or compromise."]]}, {"n": 111, "s": "A 33-year-old G2P1 at 39 weeks delivers by normal vaginal delivery. Five minutes after delivery of the placenta, the uterus is atonic and there is heavy fresh vaginal bleeding of about 800 mL. The placenta appeared complete. What is the FIRST drug to give?", "o": [["A", "IV oxytocin 10 units (slow bolus or infusion)"], ["B", "IM carboprost (15-methyl PGF2a) 250 mcg"], ["C", "IM ergometrine 0.5 mg"], ["D", "Oral misoprostol 600 mcg"]], "c": ["A)", "IV oxytocin 10 units (slow bolus or infusion)"], "co": "Postpartum haemorrhage — first-line uterotonic", "ct": "Recall (PPH drug ladder)", "w": "Atonic postpartum haemorrhage management is a stepwise ladder: first-line oxytocin (slow IV 10 units, or 10 units IM in settings without IV access); if ineffective, add ergometrine (0.5 mg IM, avoid in hypertension), carboprost (IM, avoid in asthma), or misoprostol. Simultaneously: call for help, massage the uterus, examine for retained tissue/trauma, give fluids, and monitor for coagulopathy. Carboprost/ergometrine are second-line, not first.", "d": "Atonic PPH: first-line oxytocin (10 IU IV/IM) during active management; second-line ergometrine, carboprost, misoprostol", "t": "Drug-order trap — jumping to the second-line uterotonic before oxytocin", "f": "Atonic PPH: oxytocin first, then ergometrine (no hypertension), carboprost (no asthma), misoprostol; treat cause simultaneously.", "r": "PPH: A—airway, B—breathing, C—circulation, D—drugs (oxytocin first), E—evacuate retained tissue, F—foley/tamponade, G—gonadotomy/laparotomy as escalation; document blood loss and trigger massive transfusion early.", "x": [["B) IM carboprost (15-methyl PGF2a) 250 mcg", "Carboprost is a second-line uterotonic (also avoided in asthma); oxytocin comes first."], ["C) IM ergometrine 0.5 mg", "Ergometrine is second-line and contraindicated in hypertension/pre-eclampsia."], ["D) Oral misoprostol 600 mcg", "Misoprostol is an adjunct/rescue uterotonic where injectables are unavailable, not the first-line choice."]]}, {"n": 112, "s": "A 38-year-old G5P4 has prolonged premature rupture of membranes at 33 weeks. She is afebrile but the CTG shows a baseline of 170 bpm with reduced variability. What is the most appropriate management?", "o": [["A", "Expectant management with weekly review"], ["B", "Ampicillin and erythromycin IV, betamethasone, and delivery at 34 weeks"], ["C", "Immediate delivery regardless of gestation"], ["D", "Oral co-amoxiclav and discharge home"]], "c": ["B)", "Ampicillin and erythromycin IV, betamethasone, and delivery at 34 weeks"], "co": "PPROM — antibiotics, steroids, and chorioamnionitis recognition", "ct": "Interpretation (PPROM + fetal tachycardia = chorioamnionitis until proven)", "w": "PPROM at 33 weeks: give parenteral antibiotics (ampicillin + erythromycin in some protocols; local guideline-based) to prolong latency, and betamethasone for lung maturity if not already given. Fetal tachycardia with reduced variability despite maternal wellbeing is a red flag for chorioamnionitis — the decision is to deliver at 34 weeks or emergently if chorioamnionitis is confirmed. Co-amoxiclav is avoided for PPROM (necrotising enterocolitis association in the newborn).", "d": "PPROM <34 weeks: latency antibiotics + corticosteroids; fetal tachycardia with reduced variability = chorioamnionitis → deliver after stabilisation", "t": "Missed-infection trap — attributing fetal tachycardia to prematurity rather than chorioamnionitis", "f": "PPROM + fetal tachycardia/reduced variability = chorioamnionitis → delivery; antibiotics + steroids before.", "r": "PPROM <34 weeks: antibiotics (latency), betamethasone; deliver for chorioamnionitis (fetal tachycardia, uterine tenderness, maternal fever) or at 34 weeks; avoid co-amoxiclav.", "x": [["A) Expectant management with weekly review", "Weekly review ignores a now-abnormal CTG suggesting chorioamnionitis; expectant care would prolong intrauterine infection."], ["C) Immediate delivery regardless of gestation", "Immediate delivery at 33 weeks without steroids and antibiotics needlessly adds prematurity morbidity; stabilise first."], ["D) Oral co-amoxiclav and discharge home", "Discharge is unsafe with a suspicious CTG; co-amoxiclav is specifically avoided in PPROM for NEC risk."]]}, {"n": 113, "s": "A 31-year-old G1P0 at 36 weeks reports reduced fetal movements over the last 24 hours. The non-stress test is reactive but the ultrasound shows an amniotic fluid index of 4 cm. What is the most appropriate next step?", "o": [["A", "Deliver by caesarean today"], ["B", "Admit for fetal surveillance: biophysical profile, CTG, and serial assessment"], ["C", "Reassure and discharge without follow-up"], ["D", "Amnioinfusion in the outpatient setting"]], "c": ["B)", "Admit for fetal surveillance: biophysical profile, CTG, and serial assessment"], "co": "Oligohydramnios at term — surveillance plan", "ct": "Interpretation (reduced movements + oligohydramnios = high-risk surveillance)", "w": "Oligohydramnios (AFI ≤5 cm) at term increases the risk of cord compression and adverse outcome, especially with reduced fetal movements. Management: admission with CTG monitoring, biophysical profile, assessment of growth, and counselling; induction of labour is often recommended at term (37+ weeks) or earlier for abnormal surveillance. A reactive CTG alone is not enough to discharge — the AFI warrants ongoing assessment.", "d": "Oligohydramnios (AFI <5 cm) at term with reduced movements = admit for BPP and CTG surveillance; delivery timing depends on status", "t": "Checklist-only trap — the reactive CTG that lulls you into dismissing oligohydramnios", "f": "AFI ≤5 at term = oligohydramnios → admit, BPP/CTG surveillance, plan induction at 37 weeks or earlier if abnormal.", "r": "Oligohydramnios: confirm with AFI/MPV, assess with BPP and growth scan, monitor CTG; deliver at term or when surveillance is abnormal; counsel on risk of cord compromise.", "x": [["A) Deliver by caesarean today", "Immediate caesarean at 36 weeks is premature; surveillance and planned induction/term delivery are appropriate first."], ["C) Reassure and discharge without follow-up", "Discharging with an abnormal AFI and reduced movements misses the window to prevent cord-related morbidity."], ["D) Amnioinfusion in the outpatient setting", "Amnioinfusion is an intrapartum intervention for variable decelerations, not an outpatient therapy for oligohydramnios."]]}, {"n": 114, "s": "A 27-year-old G1P0 at 28 weeks complains of intense itching, worse at night, with no rash. Liver function tests show a bile acid level of 28 micromol/L. What is the most important fetal risk to counsel about?", "o": [["A", "Congenital infection"], ["B", "Intrahepatic cholestasis of pregnancy — risk of stillbirth and preterm birth"], ["C", "Placenta praevia"], ["D", "Gestational diabetes"]], "c": ["B)", "Intrahepatic cholestasis of pregnancy — risk of stillbirth and preterm birth"], "co": "Intrahepatic cholestasis of pregnancy — fetal risks", "ct": "Interpretation (pruritus + elevated bile acids = ICP)", "w": "Intrahepatic cholestasis of pregnancy presents with pruritus (palms/soles often worst) without rash and elevated total bile acids. Fetal risks: preterm birth, meconium-stained liquor, and stillbirth — risk rises with bile acid levels ≥40 micromol/L. Management: ursodeoxycholic acid (symptom relief/modest bile acid reduction), regular monitoring of bile acids and CTG, and delivery around 36–37 weeks depending on severity (earlier for severe disease).", "d": "Night-time pruritus without rash + bile acids ≥10–14 micromol/L = ICP; main risk is stillbirth, so monitor bile acids and plan early delivery", "t": "Rash-expectation trap — dismissing cholestasis because the itch has no visible rash", "f": "Pruritus without rash in pregnancy = check bile acids; ICP → UDCA, monitor, plan early term delivery; stillbirth risk is the core counselling point.", "r": "ICP: pruritus + bile acids ≥10 micromol/L; manage with UDCA, fetal surveillance, delivery 36–37 weeks (earlier if bile acids ≥40 or symptoms severe); risk of stillbirth drives timing.", "x": [["A) Congenital infection", "Congenital infection would present with fever, rash, or growth issues, not isolated nocturnal pruritus with high bile acids."], ["C) Placenta praevia", "Praevia presents with painless bleeding, not itching with abnormal liver biochemistry."], ["D) Gestational diabetes", "GDM causes polyhydramnios/macrosomia but does not explain pruritus or raised bile acids."]]}, {"n": 115, "s": "A 24-year-old woman presents at 10 weeks with a temperature of 38.9 C, uterine tenderness, and a purulent cervical discharge. She has an intrauterine contraceptive device in situ. What is the most appropriate management?", "o": [["A", "Remove the IUCD before starting antibiotics"], ["B", "Start broad-spectrum antibiotics and remove the IUCD once treatment has begun"], ["C", "Treat the discharge with metronidazole cream only"], ["D", "Watch and review in 48 hours"]], "c": ["B)", "Start broad-spectrum antibiotics and remove the IUCD once treatment has begun"], "co": "Pelvic inflammatory disease with IUCD — antibiotic first approach", "ct": "Interpretation (fever + uterine tenderness + purulent discharge = PID; IUCD in place)", "w": "Acute PID (fever, uterine/cervical motion tenderness, purulent discharge) with an IUCD in situ: start broad-spectrum antibiotics immediately (ceftriaxone + doxycycline ± metronidazole in most protocols), then remove the IUCD shortly after antibiotics begin — removal before antibiotics worsens bacteraemia risk. Admission is required when there is fever, pregnancy, or tubo-ovarian abscess. The woman is 10 weeks pregnant here — pregnancy with PID is an admission criterion.", "d": "In PID with an IUCD, antibiotics are started first; IUCD removal is done after antibiotics have commenced (within 24–48 h), not before", "t": "Order trap — removing the device first and burning the antibiotic window", "f": "PID + IUCD: antibiotics FIRST, then device removal; admit if pregnant, febrile, or abscess suspected.", "r": "PID: broad-spectrum antibiotics (ceftriaxone + doxycycline ± metronidazole); remove IUCD only after antibiotics started; admit pregnant women, febrile patients, or suspected tubo-ovarian abscess.", "x": [["A) Remove the IUCD before starting antibiotics", "Removing the device before antibiotics increases the chance of disseminating infection; treat first."], ["C) Treat the discharge with metronidazole cream only", "Topical metronidazole does not treat upper genital tract infection and ignores the need for systemic coverage."], ["D) Watch and review in 48 hours", "Observation delays care for a febrile pregnant woman with PID — an admission-level condition."]]}, {"n": 116, "s": "A 35-year-old man and his 32-year-old partner present with 2 years of primary infertility. Semen analysis shows sperm count 4 million/mL, normal morphology and motility. Partner's ovulation and tubal patency are normal. What is the most appropriate first-line fertility treatment?", "o": [["A", "Intrauterine insemination with partner sperm"], ["B", "Intracytoplasmic sperm injection (ICSI) with IVF"], ["C", "Continued expectant management for another 12 months"], ["D", "Donor sperm insemination"]], "c": ["B)", "Intracytoplasmic sperm injection (ICSI) with IVF"], "co": "Male factor infertility — ICSI indication", "ct": "Interpretation (severe oligospermia → ICSI)", "w": "Severe oligospermia (<5 million/mL) is a clear male-factor indication for intracytoplasmic sperm injection (ICSI) — a single sperm is injected into each oocyte, overcoming count and function problems. IUI is suited to mild male factor/mild unexplained infertility (counts usually >10–15 million). Expectant management for another year after 2 years of infertility with a severely abnormal count is not appropriate, and donor sperm is only for azoospermia where surgical retrieval fails.", "d": "Sperm count <5 million/mL with normal tubes/ovulation = severe male factor; ICSI is the first-line assisted conception approach", "t": "Mild-to-severe confusion — offering IUI for severe oligospermia that demands ICSI", "f": "Count <5 million/mL = severe male factor → ICSI; IUI only for mild abnormalities; donor sperm for confirmed azoospermia.", "r": "Severe oligospermia (<5 million/mL): IVF with ICSI. Mild male factor/unexplained: IUI (or IVF). Azoospermia: testicular sperm extraction + ICSI, or donor sperm.", "x": [["A) Intrauterine insemination with partner sperm", "IUI requires adequate sperm numbers (typically >10–15 million); at 4 million/mL, fertilisation rates with IUI are poor."], ["C) Continued expectant management for another 12 months", "Two years of infertility with severe oligospermia already warrants ART; further expectant waiting rarely succeeds."], ["D) Donor sperm insemination", "Donor sperm is reserved for uncorrectable azoospermia after surgical sperm retrieval fails, not first-line oligospermia."]]}, {"n": 117, "s": "During a thyroidectomy, the surgeon identifies a nerve passing deep to the sternothyroid muscle, closely applied to the thyroid gland capsule. Which nerve is at greatest risk if it is not recognised?", "o": [["A", "Vagus nerve"], ["B", "Recurrent laryngeal nerve"], ["C", "Hypoglossal nerve"], ["D", "Phrenic nerve"]], "c": ["B)", "Recurrent laryngeal nerve"], "co": "Anatomy — recurrent laryngeal nerve relations in thyroid surgery", "ct": "Recall (surgical anatomy relations)", "w": "The recurrent laryngeal nerve ascends in the tracheo-oesophageal groove, passes deep to the sternothyroid muscle, and is intimately related to the thyroid gland capsule near the inferior thyroid artery — making it the classic at-risk nerve in thyroid surgery. Injury causes ipsilateral vocal cord paralysis (hoarseness; bilateral injury causes airway obstruction). The external branch of the superior laryngeal nerve is also at risk near the superior pole.", "d": "The recurrent laryngeal nerve runs in the tracheo-oesophageal groove, deep to the sternothyroid, closely related to the thyroid capsule and inferior thyroid artery", "t": "Close-relation trap — assuming the nerve of concern is the vagus rather than its laryngeal branch", "f": "RLN: tracheo-oesophageal groove, deep to sternothyroid, near inferior thyroid artery; protect in thyroidectomy; bilateral injury = stridor.", "r": "Recurrent laryngeal nerve: arises from vagus, hooks around subclavian (right) or aorta (left), ascends tracheo-oesophageal groove; injury = vocal cord paralysis; identify it before dividing inferior thyroid artery branches.", "x": [["A) Vagus nerve", "The vagus lies in the carotid sheath and is not in direct contact with the thyroid capsule during routine dissection."], ["C) Hypoglossal nerve", "The hypoglossal nerve supplies tongue muscles and runs in the carotid triangle, not near the thyroid gland."], ["D) Phrenic nerve", "The phrenic nerve runs on scalenus anterior and innervates the diaphragm — outside the thyroid bed."]]}, {"n": 118, "s": "A patient with a stab wound at the root of the neck has winged scapula when pushing against a wall. Which nerve is injured?", "o": [["A", "Long thoracic nerve"], ["B", "Accessory nerve"], ["C", "Dorsal scapular nerve"], ["D", "Thoracodorsal nerve"]], "c": ["A)", "Long thoracic nerve"], "co": "Anatomy — long thoracic nerve and winged scapula", "ct": "Recall (nerve injury pattern)", "w": "The long thoracic nerve (C5–C7) supplies serratus anterior. Injury (trauma, mastectomy/axillary dissection, strenuous activity) paralyses serratus anterior, causing winging of the scapula — especially when pushing against a wall or raising the arm. The accessory nerve innervates trapezius (shoulder droop); dorsal scapular supplies rhomboids (lateral winging); thoracodorsal supplies latissimus dorsi (weak adduction/medial rotation).", "d": "Winging of the scapula on pushing = serratus anterior weakness = long thoracic nerve injury", "t": "Winging localisation trap — thoracic (medial winging) vs dorsal scapular/accessory (lateral winging)", "f": "Medial scapular winging on forward push = long thoracic nerve (serratus anterior); lateral winging = rhomboids (dorsal scapular).", "r": "Long thoracic nerve: C5–C7, supplies serratus anterior, runs on the outer surface of the muscle; injury → medial scapular winging on push-off; risk in axillary surgery and blow to the neck/shoulder.", "x": [["B) Accessory nerve", "Accessory nerve injury causes shoulder droop and weak shoulder elevation (trapezius), not scapular winging on pushing."], ["C) Dorsal scapular nerve", "Dorsal scapular nerve (rhomboids) causes lateral winging at rest, not the classic push-off medial winging."], ["D) Thoracodorsal nerve", "Thoracodorsal nerve (latissimus dorsi) produces weakness in adduction, not winging."]]}, {"n": 119, "s": "A 45-year-old man with cirrhosis has 4 L of ascites drained. Which of the following structures lies in the lesser sac and is at risk during paracentesis through the midline?", "o": [["A", "Aorta"], ["B", "Stomach (posterior wall)"], ["C", "Urinary bladder"], ["D", "Spleen"]], "c": ["B)", "Stomach (posterior wall)"], "co": "Anatomy — lesser sac contents and paracentesis safety", "ct": "Recall (peritoneal cavity compartments)", "w": "The lesser sac (omental bursa) is the peritoneal compartment behind the stomach; its contents/relations include the stomach posterior wall, pancreas, and splenic vessels, with the epiploic foramen (Winslow) as the only communication to the greater sac. Midline paracentesis is performed in the avascular midline below the umbilicus to avoid the inferior epigastric arteries; the chief visceral risk is distended bladder/bowel, and deep midline entry above the umbilicus can reach the lesser sac and its gastric wall.", "d": "The lesser sac lies behind the stomach; midline paracentesis below the umbilicus mainly risks bladder/bowel, while the stomach's posterior wall faces the lesser sac", "t": "Compartment trap — failing to distinguish lesser sac (behind stomach) from greater sac structures", "f": "Lesser sac: posterior to stomach, contains pancreas + splenic vessels; accessed via epiploic foramen; relevant in abscess drainage and paracentesis depth.", "r": "Lesser sac boundaries: stomach/gastrocolic ligament anterior, parietal peritoneum posterior, pancreas posteroinferior; communicates with greater sac only through epiploic foramen; clinical relevance: lesser sac abscess, gastric posterior wall surgery.", "x": [["A) Aorta", "The aorta is retroperitoneal, not inside the lesser sac."], ["C) Urinary bladder", "The bladder is extraperitoneal in the pelvis; it is relevant to paracentesis as a puncture risk, not a lesser sac structure."], ["D) Spleen", "The spleen is intraperitoneal but lies in the left hypochondrium in the greater sac, not within the lesser sac."]]}, {"n": 120, "s": "A medical student is asked to locate the midpoint of the inguinal ligament to perform a femoral pulse examination. Which anatomical landmark defines the midpoint of the inguinal ligament, and what clinically important structure lies immediately beneath it?", "o": [["A", "Midway between pubic tubercle and anterior superior iliac spine; femoral artery"], ["B", "Midway between pubic symphysis and ASIS; femoral nerve"], ["C", "Just medial to the femoral vein; saphenous opening"], ["D", "Midway between umbilicus and pubic tubercle; external iliac artery"]], "c": ["A)", "Midway between pubic tubercle and anterior superior iliac spine; femoral artery"], "co": "Anatomy — inguinal ligament and femoral triangle landmarks", "ct": "Recall (surface anatomy landmark)", "w": "The mid-inguinal point — halfway between the pubic tubercle and the ASIS — overlies the femoral artery as it passes beneath the inguinal ligament into the femoral triangle. (Contrast: the midpoint of the inguinal ligament itself is the femoral nerve.) Structures from lateral to medial in the femoral triangle: nerve, artery, vein, empty space (NAVEL). This landmark is used for femoral pulse and arterial access.", "d": "Mid-inguinal point (midway between pubic tubercle and ASIS) marks the femoral artery; the midpoint of the inguinal ligament marks the femoral nerve (lateral)", "t": "Classic swap trap — mid-inguinal point (artery) vs midpoint of ligament (nerve)", "f": "Mid-inguinal point = femoral artery (compress against head of femur for haemorrhage); NAVEL across the femoral triangle.", "r": "Femoral triangle: boundaries (inguinal ligament, sartorius, adductor longus); contents NAVEL — nerve (most lateral), artery, vein, empty space, lymphatics (most medial); mid-inguinal point = artery.", "x": [["B) Midway between pubic symphysis and ASIS; femoral nerve", "The femoral nerve lies at the midpoint of the inguinal ligament, lateral to the artery — not at the mid-inguinal point."], ["C) Just medial to the femoral vein; saphenous opening", "The saphenous opening is a hiatus in fascia lata 3–4 cm below and lateral to the pubic tubercle, not beneath the mid-inguinal point."], ["D) Midway between umbilicus and pubic tubercle; external iliac artery", "The external iliac artery becomes the femoral artery exactly at the inguinal ligament; the umbilicus–pubic tubercle line is not the landmark used."]]}, {"n": 121, "s": "A 60-year-old man presents with inability to adduct the thigh after hip replacement surgery. Which nerve is most likely injured, and what muscle group does it supply?", "o": [["A", "Obturator nerve; adductor muscles of the thigh"], ["B", "Femoral nerve; quadriceps femoris"], ["C", "Sciatic nerve; hamstrings"], ["D", "Superior gluteal nerve; abductors"]], "c": ["A)", "Obturator nerve; adductor muscles of the thigh"], "co": "Anatomy — obturator nerve and thigh adductors", "ct": "Recall (nerve–muscle correlation)", "w": "The obturator nerve (L2–L4) passes through the obturator canal and supplies all adductor muscles of the thigh; injury (hip surgery, pelvic fractures, obturator hernia) causes weak adduction and a characteristic difficulty crossing the legs. The femoral nerve supplies the quadriceps (knee extension) and anterior thigh; the sciatic supplies hamstrings (flexion) and everything below the knee; the superior gluteal supplies abductors (gluteus medius/minimus) with Trendelenburg gait.", "d": "Thigh adduction is by the adductor group (adductor longus/brevis/magnus, gracilis, obturator externus) supplied by the obturator nerve (L2–L4)", "t": "Side-location trap — confusing adductors (obturator) with abductors (superior gluteal) and their gaits", "f": "Adduction loss = obturator nerve; abduction loss/Trendelenburg = superior gluteal nerve; knee extension loss = femoral; foot drop = sciatic/common peroneal.", "r": "Obturator nerve: from lumbar plexus (L2–L4), exits via obturator canal, anterior/posterior divisions supply adductor longus/brevis/magnus, gracilis, obturator externus; cutaneous branch to medial thigh; injury → weak adduction.", "x": [["B) Femoral nerve; quadriceps femoris", "Femoral nerve supplies the quadriceps and anterior thigh — knee extension, not adduction."], ["C) Sciatic nerve; hamstrings", "Sciatic nerve supplies hamstrings and all leg/foot muscles below the knee, not the adductors."], ["D) Superior gluteal nerve; abductors", "Superior gluteal injury gives weak abduction and a Trendelenburg lurch, not adductor weakness."]]}, {"n": 122, "s": "During a cadaveric dissection of the posterior triangle of the neck, a vessel is found crossing the scalenus anterior muscle anteriorly. Which structure is it, and what lies immediately posterior to the scalenus anterior?", "o": [["A", "Subclavian vein; subclavian artery and brachial plexus"], ["B", "Subclavian artery; phrenic nerve"], ["C", "External jugular vein; vagus nerve"], ["D", "Thoracic duct; brachial plexus roots"]], "c": ["A)", "Subclavian vein; subclavian artery and brachial plexus"], "co": "Anatomy — scalenus anterior relations", "ct": "Recall (triangle relations)", "w": "In the root of the neck, the subclavian vein lies anterior to scalenus anterior; the subclavian artery and brachial plexus pass between scalenus anterior and scalenus medius (the scalene gap/interscalene triangle) — posterior to scalenus anterior. The phrenic nerve descends on the ANTERIOR surface of scalenus anterior. The thoracic duct drains into the left venous angle. This anatomy is the basis for interscalene blocks and subclavian access.", "d": "Subclavian vein crosses anterior to scalenus anterior; subclavian artery and brachial plexus trunks pass posterior (scalene gap between anterior and medius)", "t": "Layer trap — swapping vein (anterior) with artery (posterior to scalenus anterior)", "f": "Scalenus anterior: vein in front, artery+plexus behind (interscalene gap), phrenic nerve on its surface; subclavian access aims between these.", "r": "Scalenus anterior relations: anterior — subclavian vein, phrenic nerve (on muscle); posterior — subclavian artery, brachial plexus trunks; medial — vertebral vessels, dome of pleura; insertion — scalene tubercle of first rib.", "x": [["B) Subclavian artery; phrenic nerve", "The subclavian artery passes posterior (in the scalene gap), not anterior; the phrenic nerve lies ON scalenus anterior, not behind it."], ["C) External jugular vein; vagus nerve", "The external jugular vein crosses the roof of the posterior triangle, not deep to scalenus anterior."], ["D) Thoracic duct; brachial plexus roots", "The thoracic duct arches into the left venous angle and is not related to scalenus anterior in the scalene gap context."]]}, {"n": 123, "s": "A 55-year-old woman with carpal tunnel syndrome has wasting of the lateral thenar eminence. Which muscle is primarily affected, and which nerve supplies it?", "o": [["A", "Abductor pollicis brevis; median nerve"], ["B", "Adductor pollicis; ulnar nerve"], ["C", "Opponens pollicis; radial nerve"], ["D", "Flexor pollicis longus; anterior interosseous nerve"]], "c": ["A)", "Abductor pollicis brevis; median nerve"], "co": "Anatomy — median nerve thenar supply", "ct": "Recall (nerve–muscle correlation in CTS)", "w": "The median nerve's recurrent (thenar) branch supplies abductor pollicis brevis, opponens pollicis, and the superficial head of flexor pollicis brevis — the lateral thenar eminence. Chronic carpal tunnel syndrome causes wasting here plus sensory loss over the lateral 3.5 digits (sparing the thenar eminence itself, supplied by palmar cutaneous branch). Adductor pollicis is ulnar; flexor pollicis longus is anterior interosseous (median); the radial nerve supplies wrist/finger extensors, not thenar muscles.", "d": "Carpal tunnel syndrome compresses the median nerve; the thenar muscles it supplies (abductor pollicis brevis, opponens pollicis, superficial head of flexor pollicis brevis) waste laterally", "t": "Nerve-mix trap — attributing thenar wasting to ulnar nerve, which actually supplies adductor pollicis", "f": "CTS: thenar wasting → median recurrent branch; clinical tests (Tinel/Phalen), nerve conduction; carpal tunnel release protects the thenar branch.", "r": "Median nerve through carpal tunnel: recurrent branch to lateral thenar muscles (APB, opponens, superficial FPB); palmar cutaneous branch (spared) supplies thenar skin; ulnar nerve supplies adductor pollicis and deep head of FPB.", "x": [["B) Adductor pollicis; ulnar nerve", "Adductor pollicis is supplied by the deep branch of the ulnar nerve — wasting here points to ulnar, not median, pathology."], ["C) Opponens pollicis; radial nerve", "The radial nerve does not supply thenar muscles; it extends the wrist/fingers and supinates the forearm."], ["D) Flexor pollicis longus; anterior interosseous nerve", "Flexor pollicis longus is anterior interosseous (median origin) but lies in the forearm, not the thenar eminence; it does not cause eminence wasting."]]}, {"n": 124, "s": "A 70-year-old man has a right-sided foot drop after a total hip replacement. He can still extend his knee and adduct the thigh. Which nerve injury best explains this pattern?", "o": [["A", "Common peroneal (fibular) nerve"], ["B", "Sciatic nerve"], ["C", "Obturator nerve"], ["D", "Femoral nerve"]], "c": ["A)", "Common peroneal (fibular) nerve"], "co": "Anatomy — common peroneal nerve and foot drop", "ct": "Interpretation (isolated foot drop with spared knee/adduction → common peroneal)", "w": "Foot drop (weak ankle dorsiflexion and eversion) with preserved knee flexion, knee extension, and thigh adduction localises to the common peroneal (fibular) nerve — the lateral division of the sciatic that winds around the fibular neck. It is susceptible to compression/positional injury during hip surgery and at the fibular head (fibular neck). Sciatic injury would add hamstring weakness; femoral injury would lose knee extension; obturator injury would lose adduction.", "d": "Foot drop with preserved knee extension and adduction = common peroneal (fibular) nerve, not sciatic; the peroneal division is vulnerable in hip surgery and at the fibular neck", "t": "Proximal-vs-distal trap — assuming hip surgery injured the whole sciatic nerve when only its peroneal division is affected", "f": "Foot drop after hip surgery = common peroneal nerve (lateral division of sciatic); test knee flexion (hamstrings, sciatic) and knee extension (femoral) to localise.", "r": "Common peroneal (fibular) nerve: winds around fibular neck, supplies dorsiflexors/everters; injury → foot drop with high-steppage gait, sensory loss over dorsum of foot and lateral leg; sciatic injury spares nothing below the knee and weakens hamstrings.", "x": [["B) Sciatic nerve", "Sciatic injury would also weaken hamstrings (knee flexion) — preserved knee flexion points to a distal peroneal lesion."], ["C) Obturator nerve", "Obturator injury causes weak adduction; a patient who can still adduct has an intact obturator."], ["D) Femoral nerve", "Femoral injury causes weak knee extension (quadriceps) — preserved extension excludes it."]]}, {"n": 125, "s": "During a Whipple procedure (pancreaticoduodenectomy), the surgeon must preserve a structure passing between the duodenum and the porta hepatis within the hepatoduodenal ligament. Which of these is contained in the free edge of the lesser omentum?", "o": [["A", "Common hepatic duct only"], ["B", "Portal vein, hepatic artery, and bile duct"], ["C", "Splenic artery and vein"], ["D", "Gastric vessels and coeliac trunk"]], "c": ["B)", "Portal vein, hepatic artery, and bile duct"], "co": "Anatomy — hepatoduodenal ligament contents", "ct": "Recall (ligament contents)", "w": "The hepatoduodenal ligament is the thickened free right edge of the lesser omentum, connecting the porta hepatis to the duodenum. It contains the portal triad — bile duct (anterolateral), hepatic artery (anteromedial), and portal vein (posterior) — plus lymphatics and the hepatic plexus. The epiploic foramen (Winslow) lies behind it. The coeliac trunk, splenic vessels, and gastric vessels are in the retroperitoneum/ligaments elsewhere.", "d": "The free edge of the lesser omentum (hepatoduodenal ligament) contains the portal triad: portal vein, hepatic artery, common bile duct", "t": "Triad-order trap — knowing the three structures but not their arrangement (D-A-V anterior to posterior)", "f": "Portal triad in hepatoduodenal ligament: bile duct, hepatic artery, portal vein (anterior→posterior); Pringle manoeuvre compresses all three.", "r": "Free edge of lesser omentum: common bile duct, hepatic artery, portal vein + hepatic plexus and lymphatics; posterior relation is the epiploic foramen; Pringle manoeuvre occludes the triad to control hepatic bleeding.", "x": [["A) Common hepatic duct only", "The bile duct is one element of the triad; the ligament carries the artery and portal vein as well."], ["C) Splenic artery and vein", "Splenic vessels run in the splenorenal ligament/gastro-splenic regions, not the hepatoduodenal ligament."], ["D) Gastric vessels and coeliac trunk", "Gastric vessels run in the hepatogastric part of the lesser omentum; the coeliac trunk is retroperitoneal."]]}, {"n": 126, "s": "A 30-year-old woman has ptosis, a constricted pupil, and absence of sweating on the right side of the face after a Pancoast (apical lung) tumour. Which structure is compressed, and where does the sympathetic pathway exit the spinal cord?", "o": [["A", "Sympathetic trunk at T1; lateral horn of the spinal cord at T1"], ["B", "Vagus nerve; dorsal motor nucleus"], ["C", "Facial nerve; superior salivatory nucleus"], ["D", "Cervical plexus; anterior horn of C8"]], "c": ["A)", "Sympathetic trunk at T1; lateral horn of the spinal cord at T1"], "co": "Anatomy — Horner syndrome and sympathetic pathway", "ct": "Interpretation (Pancoast tumour → Horner syndrome)", "w": "Horner syndrome — ptosis, miosis, anhidrosis, enophthalmos — results from interruption of the oculosympathetic pathway. The preganglionic fibres arise in the lateral horn (intermediolateral cell column) of T1–T2, ascend the sympathetic trunk, and synapse at the superior cervical ganglion; postganglionic fibres travel with the internal carotid artery to the eye and face. A Pancoast tumour at the lung apex compresses this trunk (also causing shoulder/arm pain and hand wasting via C8–T1 plexus).", "d": "Apical lung tumour compresses the cervical sympathetic trunk; the preganglionic sympathetic fibres for the face/eye exit the cord at T1 (and T2), ascend in the sympathetic trunk to the superior cervical ganglion", "t": "Localisation trap — placing the lesion in the eye or third nerve instead of the sympathetic trunk", "f": "Ptosis + miosis + anhidrosis = Horner; with apical lung mass = Pancoast; investigate chest apex (CXR/CT), distinguish central vs pre/postganglionic.", "r": "Oculosympathetic pathway: hypothalamus → lateral horn T1–T2 → sympathetic trunk → superior cervical ganglion → ICA plexus → dilator pupillae, Muller muscle, sweat glands; Pancoast tumour compresses it at the lung apex.", "x": [["B) Vagus nerve; dorsal motor nucleus", "The vagus carries parasympathetic fibres and does not produce Horner syndrome when compressed."], ["C) Facial nerve; superior salivatory nucleus", "The facial nerve (parasympathetic to lacrimal/glands) produces different cranial nerve findings, not anhidrosis with ptosis/miosis."], ["D) Cervical plexus; anterior horn of C8", "Cervical plexus and anterior horn pathology do not explain the triad; the pathway is sympathetic, from T1–T2 lateral horn."]]}, {"n": 127, "s": "A patient with an L4/L5 disc herniation has weak ankle dorsiflexion and toe extension. Dermatomal sensory loss is expected over which region?", "o": [["A", "Medial foot and big toe"], ["B", "Lateral foot and little toe"], ["C", "Medial calf"], ["D", "Lateral thigh"]], "c": ["A)", "Medial foot and big toe"], "co": "Anatomy — L5 nerve root dermatome and myotome", "ct": "Recall (nerve root level)", "w": "The L5 nerve root (compressed by an L4/L5 disc) supplies the dorsiflexors (tibialis anterior) and toe extensors, with a dermatome over the medial foot/big toe and the lateral leg. L4 root affects knee extension and the medial calf; S1 affects ankle plantarflexion/reflex and lateral foot; L2–L3 affect the medial/lateral thigh. Nerve root compression must be distinguished from a common peroneal nerve lesion, which spares sensation over the medial foot (L4/L5 supply) — actually peroneal spares the medial foot, helping differentiate.", "d": "L5 root: weak ankle dorsiflexion/toe extension (L5 myotome) with sensory loss over the medial foot and big toe (L5 dermatome)", "t": "Level swap trap — L5 vs S1 root (dorsiflexion/big toe vs plantarflexion/lateral foot)", "f": "L4/L5 disc → L5 root: foot drop pattern + big toe sensory loss; S1 root: plantarflexion weak + lateral foot + absent ankle jerk.", "r": "L5: dorsiflexion and toe extension weak, sensory loss medial foot/big toe; reflex intact; L4: knee extension weak, medial calf; S1: plantarflexion weak, ankle jerk absent, lateral foot.", "x": [["B) Lateral foot and little toe", "Lateral foot and little toe sensory loss with weak plantarflexion describes S1, not L5."], ["C) Medial calf", "Medial calf sensory loss is L4, paired with quadriceps weakness and reduced knee jerk."], ["D) Lateral thigh", "Lateral thigh sensory loss is L2/L3 territory with hip flexor and adductor involvement, not dorsiflexion weakness."]]}, {"n": 128, "s": "A 2-day-old neonate becomes lethargic, vomits, and develops a sweet-smelling urine. Plasma ammonia is 300 micromol/L and the blood glucose is normal. Which enzyme deficiency classically causes this presentation?", "o": [["A", "Ornithine transcarbamylase deficiency (urea cycle)"], ["B", "Glucose-6-phosphatase deficiency"], ["C", "Phenylalanine hydroxylase deficiency"], ["D", "Galactose-1-phosphate uridyltransferase deficiency"]], "c": ["A)", "Ornithine transcarbamylase deficiency (urea cycle)"], "co": "Biochemistry — urea cycle and hyperammonaemia", "ct": "Interpretation (neonatal hyperammonaemia + sweet odour → urea cycle defect)", "w": "The urea cycle converts toxic ammonia to urea. A defect (most commonly ornithine transcarbamylase, X-linked) causes severe neonatal hyperammonaemia with vomiting, lethargy, coma, and respiratory alkalosis — often with a musty/sweet odour. OTC deficiency is the most common urea cycle defect. G6Pase deficiency causes fasting hypoglycaemia/lactic acidosis; PKU causes intellectual disability with musty odour but not hyperammonaemia; classic galactosaemia causes jaundice, cataracts, and liver failure with reducing substances in urine.", "d": "Hyperammonaemia with normal glucose in a neonate = urea cycle disorder; OTC (X-linked) is the most common, and the 'sweet-smelling' urine fits hyperammonaemic encephalopathy presentations", "t": "Odour overlap trap — 'sweet/musty' urine sending you to PKU, while the ammonia points to the urea cycle", "f": "Neonatal hyperammonaemia = urea cycle defect until proven; check ammonia, blood gas (resp alkalosis), and urine orotic acid (OTC elevated).", "r": "Urea cycle: carbamoyl phosphate → citrulline → argininosuccinate → arginine → urea + ornithine; OTC deficiency (X-linked, most common) → hyperammonaemia, low citrulline, high orotic acid; treat with ammonia scavengers, nitrogen-restricted diet, arginine supplementation, dialysis in crisis.", "x": [["B) Glucose-6-phosphatase deficiency", "Glucose-6-phosphatase deficiency (von Gierke) causes fasting hypoglycaemia, lactic acidosis, and hepatomegaly — not hyperammonaemia."], ["C) Phenylalanine hydroxylase deficiency", "Phenylalanine hydroxylase deficiency (PKU) causes intellectual disability and musty odour but normal ammonia; newborn screening measures phenylalanine."], ["D) Galactose-1-phosphate uridyltransferase deficiency", "Galactosaemia presents with jaundice, cataracts, hepatomegaly, and reducing substances in urine after milk feeds, without primary hyperammonaemia."]]}, {"n": 129, "s": "A chronic alcoholic with nausea and vomiting for 2 days presents with confusion and ophthalmoplegia. MRI shows symmetrical lesions of the mammillary bodies. Which vitamin deficiency and enzyme cofactor role explain this?", "o": [["A", "Thiamine (B1) deficiency; cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase"], ["B", "Niacin deficiency; cofactor for NAD-dependent dehydrogenases"], ["C", "Vitamin B12 deficiency; methylmalonyl-CoA mutase"], ["D", "Pyridoxine deficiency; transaminases"]], "c": ["A)", "Thiamine (B1) deficiency; cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase"], "co": "Biochemistry — Wernicke encephalopathy and thiamine", "ct": "Interpretation (alcoholic + ophthalmoplegia + mammillary bodies → Wernicke)", "w": "Wernicke encephalopathy — confusion, ataxia, ophthalmoplegia — is caused by thiamine (vitamin B1) deficiency, classically in alcoholics (impaired absorption + poor intake). MRI shows symmetrical mammillary body and periaqueductal lesions. Thiamine pyrophosphate is the cofactor for pyruvate dehydrogenase (glycolysis → acetyl-CoA), alpha-ketoglutarate dehydrogenase (TCA cycle), branched-chain ketoacid dehydrogenase, and transketolase (HMP shunt). Treatment is IV thiamine BEFORE glucose, as glucose worsens the deficiency.", "d": "Wernicke encephalopathy = thiamine deficiency; thiamine pyrophosphate is the cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase", "t": "Order trap — giving glucose without thiamine first, precipitating Wernicke or worsening it", "f": "Alcohol + confusion + ophthalmoplegia/ataxia = Wernicke; MRI mammillary bodies; IV thiamine first, then glucose.", "r": "Thiamine pyrophosphate: cofactor for pyruvate dehydrogenase, alpha-KG dehydrogenase, branched-chain ketoacid dehydrogenase, transketolase; deficiency → Wernicke (thiamine first), wet beriberi (high-output failure), dry beriberi (polyneuropathy).", "x": [["B) Niacin deficiency; cofactor for NAD-dependent dehydrogenases", "Niacin (B3) deficiency causes pellagra (dermatitis, diarrhoea, dementia) — NAD/NADP cofactor — not mammillary body lesions with ophthalmoplegia."], ["C) Vitamin B12 deficiency; methylmalonyl-CoA mutase", "B12 deficiency causes macrocytic anaemia and subacute combined degeneration (posterior/lateral columns) — methylmalonyl-CoA mutase and methionine synthase."], ["D) Pyridoxine deficiency; transaminases", "Pyridoxine deficiency causes convulsions, sideroblastic anaemia, and peripheral neuropathy — transaminase cofactor, not the Wernicke pattern."]]}, {"n": 130, "s": "A patient on a very low-carbohydrate diet develops ketosis. Which statement correctly describes ketone body metabolism?", "o": [["A", "Ketone bodies are synthesised in the liver and used as fuel by the brain during starvation"], ["B", "Ketone bodies are synthesised in muscle and oxidised in the liver"], ["C", "Acetoacetate is the only ketone body"], ["D", "Ketogenesis requires malonyl-CoA accumulation"]], "c": ["A)", "Ketone bodies are synthesised in the liver and used as fuel by the brain during starvation"], "co": "Biochemistry — ketogenesis", "ct": "Recall (ketone body physiology)", "w": "Ketone bodies — acetoacetate, beta-hydroxybutyrate (the major circulating form), and acetone — are synthesised in hepatic mitochondria from acetyl-CoA when oxaloacetate is diverted to gluconeogenesis (starvation, low-carb diet, DKA). They are exported and oxidised by extrahepatic tissues including the brain (which cannot oxidise fatty acids). Malonyl-CoA INHIBITS ketogenesis by blocking CPT-1 (fatty acid entry into mitochondria); low malonyl-CoA during fasting allows it.", "d": "Ketogenesis happens in liver mitochondria (not muscle); acetoacetate, beta-hydroxybutyrate, and acetone are the ketone bodies; the brain uses them during starvation", "t": "Site-of-synthesis trap — muscle does not make ketones; the liver makes them but cannot use them", "f": "Liver = ketone factory (but can't use them); brain/muscle = consumers; malonyl-CoA low during fasting = ketogenesis on.", "r": "Ketogenesis: hepatic mitochondrial condensation of acetyl-CoA (HMG-CoA pathway) when oxaloacetate is scarce; low insulin ↑ lipolysis and ↓ malonyl-CoA → CPT-1 active → ketogenesis; brain switches to ketones in prolonged starvation, sparing glucose and protein.", "x": [["B) Ketone bodies are synthesised in muscle and oxidised in the liver", "The liver synthesises ketone bodies but lacks the enzyme to use them; muscle is a consumer, not a producer."], ["C) Acetoacetate is the only ketone body", "Three ketone bodies exist: acetoacetate, beta-hydroxybutyrate, and acetone; acetoacetate is not the only one."], ["D) Ketogenesis requires malonyl-CoA accumulation", "Malonyl-CoA inhibits CPT-1 and thus ketogenesis; its level falls (not rises) during fasting to enable ketone production."]]}, {"n": 131, "s": "A 25-year-old medical student, after an overnight fast, develops symptoms and is found to have a blood glucose of 45 mg/dL. A glucagon stimulation test shows a normal rise in glucose. A urine dipstick shows no ketones. The most likely diagnosis is:", "o": [["A", "Insulinoma"], ["B", "Glycogen storage disease type I"], ["C", "Surreptitious insulin use (factitious hypoglycaemia)"], ["D", "Addison disease"]], "c": ["C)", "Surreptitious insulin use (factitious hypoglycaemia)"], "co": "Biochemistry — hypoglycaemia workup and C-peptide", "ct": "Analysis/synthesis (fasting hypoglycaemia + no ketones + glucagon response → insulin-mediated)", "w": "Fasting hypoglycaemia with suppressed ketones and a brisk glucose response to glucagon indicates hyperinsulinaemia (insulin suppresses lipolysis/ketogenesis and hepatic glucose output). The key discriminator is C-peptide: high insulin + LOW C-peptide = exogenous insulin (factitious); high insulin + HIGH C-peptide = endogenous (insulinoma). The normal glucagon rise (vs failure in glycogen storage disease) and the absence of ketones point away from GSD and Addison (which cause hypoketotic or ketotic hypoglycaemia differently).", "d": "Hyperinsulinaemic hypoglycaemia (insulinoma or exogenous insulin) suppresses ketogenesis and responds to glucagon; low C-peptide with high insulin = exogenous insulin (factitious), high C-peptide = insulinoma", "t": "Loophole trap — assuming endogenous hyperinsulinism without checking C-peptide for factitious insulin", "f": "Fasting hypoglycaemia + no ketones + glucagon response = insulin effect; C-peptide separates insulinoma (high) from exogenous insulin (low).", "r": "Hypoglycaemia workup: insulin, C-peptide, proinsulin, cortisol, ketones, beta-hydroxybutyrate, liver function; insulinoma = high insulin + high C-peptide + high proinsulin + hypoglycaemia + symptomatic relief by glucose (Whipple triad); factitious = high insulin + low C-peptide.", "x": [["A) Insulinoma", "Insulinoma would show HIGH C-peptide with high insulin; a normal glucagon test does not exclude it but the C-peptide pattern is the distinguishing test."], ["B) Glycogen storage disease type I", "GSD I (G6Pase) gives fasting hypoglycaemia WITH lactic acidosis and hepatomegaly; glucagon fails to raise glucose."], ["D) Addison disease", "Addison disease causes hypoglycaemia with low cortisol, hypotension, and hyperpigmentation; ketones are typically present, and glucagon response is normal but the insulin/C-peptide story differs."]]}, {"n": 132, "s": "A 45-year-old man has an elevated LDL and low HDL, with tendon xanthomata. His father died of myocardial infarction at age 48. Genetic testing identifies a defective LDL receptor. Which biochemical pathway is primarily affected?", "o": [["A", "Receptor-mediated endocytosis of LDL via clathrin-coated pits"], ["B", "HMG-CoA reductase upregulation"], ["C", "Chylomicron assembly in enterocytes"], ["D", "Lipoprotein lipase activity in capillaries"]], "c": ["A)", "Receptor-mediated endocytosis of LDL via clathrin-coated pits"], "co": "Biochemistry — LDL receptor pathway (familial hypercholesterolaemia)", "ct": "Recall (molecular mechanism of FH)", "w": "The LDL receptor binds apolipoprotein B-100/E and internalises LDL via clathrin-coated pits (receptor-mediated endocytosis). Defects in the receptor (familial hypercholesterolaemia, autosomal dominant, most often LDLR gene) reduce hepatic LDL clearance → markedly elevated LDL, tendon xanthomata, and premature coronary disease. HMG-CoA reductase is upregulated compensatory but the primary defect is the receptor; LPL deficiency gives chylomicronaemia and elevated triglycerides; chylomicron assembly is not the FH lesion.", "d": "Familial hypercholesterolaemia = defective LDL receptor → impaired receptor-mediated endocytosis of LDL via coated pits → high plasma LDL and premature atherosclerosis", "t": "Pathway-reflex trap — reaching for HMG-CoA reductase (the treatment target) instead of the receptor (the disease mechanism)", "f": "High LDL + xanthomata + family history of early MI = FH; receptor-mediated endocytosis is the broken pathway; statins act upstream (HMG-CoA reductase).", "r": "LDL receptor: binds ApoB-100, endocytoses LDL via coated pits, delivers cholesterol to lysosomes; defective receptor → FH (homozygous severe, heterozygous LDL ~2-3x normal); treat with statins ± ezetimibe/PCSK9 inhibitors (PCSK9 degrades receptors — inhibition preserves them).", "x": [["B) HMG-CoA reductase upregulation", "HMG-CoA reductase produces endogenous cholesterol; it is the statin target, not the primary defect — FH is a receptor problem."], ["C) Chylomicron assembly in enterocytes", "Chylomicron assembly defects cause fat malabsorption and failure to thrive, not tendon xanthomata with high LDL."], ["D) Lipoprotein lipase activity in capillaries", "Lipoprotein lipase deficiency causes hypertriglyceridaemia and eruptive xanthomata/pancreatitis, not an elevated LDL pattern."]]}, {"n": 133, "s": "A newborn with cataracts, jaundice, and hepatomegaly has reducing substances in the urine. Which enzyme is deficient and which confirmatory test is most specific?", "o": [["A", "Galactose-1-phosphate uridyltransferase; assay of red cell enzyme activity"], ["B", "Glucose-6-phosphatase; liver biopsy glycogen content"], ["C", "Phenylalanine hydroxylase; plasma phenylalanine"], ["D", "Lactase; breath hydrogen test"]], "c": ["A)", "Galactose-1-phosphate uridyltransferase; assay of red cell enzyme activity"], "co": "Biochemistry — classic galactosaemia", "ct": "Interpretation (cataracts + jaundice + reducing substances in urine → galactosaemia)", "w": "Classic galactosaemia is caused by deficiency of galactose-1-phosphate uridyltransferase (GALT): galactose-1-phosphate accumulates → cataracts (galactitol in lens), jaundice/liver failure, hepatomegaly, E. coli sepsis risk, and reducing substances in urine (galactose is a reducing sugar that glucose dipsticks may miss — use a reducing-substances test). Confirmation is red cell GALT enzyme assay (or DNA testing). Treatment is lifelong galactose-free diet; mothers' milk and lactose formulas must stop immediately.", "d": "Cataracts, hepatomegaly, jaundice, and reducing substances in urine (with normal glucose) after milk feeding = classic galactosaemia; definitive test = red cell galactose-1-phosphate uridyltransferase assay", "t": "Screen trap — a glucose-negative dipstick with a positive Clinitest/reducing substance result pointing to galactose, not glucose", "f": "Neonatal cataracts + jaundice + reducing substances in urine = galactosaemia; confirm GALT assay, remove lactose NOW (E. coli sepsis risk).", "r": "Galactosaemia: GALT deficiency; galactose → galactitol (cataracts) and galactose-1-P (liver damage); diagnosis by red cell GALT activity; manage with galactose-free diet; reduce substances + normal glucose on urine is the screening clue.", "x": [["B) Glucose-6-phosphatase; liver biopsy glycogen content", "G6Pase deficiency (von Gierke) causes fasting hypoglycaemia and hepatomegaly but not neonatal cataracts or urine reducing substances."], ["C) Phenylalanine hydroxylase; plasma phenylalanine", "PKU causes intellectual disability and musty odour with elevated phenylalanine — no cataracts or reducing substances."], ["D) Lactase; breath hydrogen test", "Lactase deficiency causes osmotic diarrhoea after milk, not cataracts, jaundice, and hepatomegaly in a neonate."]]}, {"n": 134, "s": "During an outbreak of watery diarrhoea in a village, 40 of 120 people who attended a wedding feast became ill within 24 hours. All cases had eaten the chicken biryani. Which measure best describes the attack rate?", "o": [["A", "40/120 = 33.3%"], ["B", "40/80 = 50%"], ["C", "120/40 = 3"], ["D", "80/120 = 66.7%"]], "c": ["A)", "40/120 = 33.3%"], "co": "Epidemiology — attack rate calculation", "ct": "Recall (measure calculation)", "w": "Attack rate is the proportion of an exposed population that develops disease during an outbreak: (cases among exposed ÷ total exposed) × 100 — here 40/120 = 33.3%. It is an incidence-type measure used in outbreak investigations. Food-specific attack rates compare illness rates between those who ate and did not eat a suspect food to identify the vehicle.", "d": "Attack rate = number of people exposed who became ill ÷ total number of exposed people (40/120), expressed as a percentage", "t": "Denominator trap — using the unexposed as the denominator, or inverting the fraction into a ratio", "f": "Attack rate = ill ÷ exposed; food-specific rates need both ate and did-not-eat groups to implicate a vehicle.", "r": "Attack rate = (number of cases among exposed ÷ total exposed) × 100 during an outbreak; compare food-specific attack rates to identify the source vehicle; person-time denominators when follow-up varies.", "x": [["B) 40/80 = 50%", "40/80 uses the 80 who did NOT fall ill as the denominator — wrong denominator; the exposed population is all 120 attendees."], ["C) 120/40 = 3", "120/40 = 3 is an inverted ratio, not a rate; rates are cases over population, not the reverse."], ["D) 80/120 = 66.7%", "80/120 = 66.7% is the proportion of attendees who stayed well — the complement, not the attack rate."]]}, {"n": 135, "s": "A screening test for tuberculosis has a sensitivity of 95% and a specificity of 90% in a population where the prevalence is 1%. What is the most accurate interpretation of these parameters?", "o": [["A", "The test will correctly identify 95% of truly diseased individuals as positive"], ["B", "A positive result means there is a 95% chance the person has the disease"], ["C", "The test correctly rules out disease in 95% of people"], ["D", "The positive predictive value will be above 90% in this population"]], "c": ["A)", "The test will correctly identify 95% of truly diseased individuals as positive"], "co": "Epidemiology — sensitivity, specificity, predictive values", "ct": "Interpretation (screening validity vs predictive value)", "w": "Sensitivity (95%) means 95 of 100 truly diseased people test positive — the test's ability to identify disease. Specificity (90%) means 90% of the non-diseased test negative. Predictive values depend heavily on prevalence: in a 1% prevalence population, PPV is roughly 8–9%, NOT >90% — most positive results are false positives. So a positive test does NOT mean 95% probability of disease.", "d": "Sensitivity = ability to detect true disease (95% of diseased test positive); PPV falls dramatically when prevalence is low despite high specificity", "t": "Predictive-value illusion — equating sensitivity with the probability that a positive result means disease", "f": "PPV varies with prevalence; a highly sensitive/specific test still floods with false positives in low-prevalence screening.", "r": "Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); PPV = TP/(TP+FP) — prevalence-dependent; NPV = TN/(TN+FN); screening is most useful where prevalence is not extremely low.", "x": [["B) A positive result means there is a 95% chance the person has the disease", "The probability that a positive result means disease is the PPV, which is low (~8%) at 1% prevalence — not 95%."], ["C) The test correctly rules out disease in 95% of people", "Correctly ruling out disease is specificity (90%), not sensitivity (95%)."], ["D) The positive predictive value will be above 90% in this population", "At 1% prevalence, PPV is far below 90% — a false-positive flood overwhelms true positives despite good specificity."]]}, {"n": 136, "s": "A cohort study follows 5,000 smokers and 5,000 non-smokers for 10 years. Lung cancer develops in 40 smokers and 5 non-smokers. What is the attributable risk (risk difference) of smoking for lung cancer?", "o": [["A", "0.7% (7 per 1,000)"], ["B", "8-fold"], ["C", "40 cases"], ["D", "0.9%"]], "c": ["A)", "0.7% (7 per 1,000)"], "co": "Epidemiology — attributable risk (risk difference)", "ct": "Recall (measure calculation)", "w": "Attributable risk (risk difference) is the excess incidence caused by the exposure: I_e − I_u = (40/5000) − (5/5000) = 0.008 − 0.001 = 0.007 = 7 per 1,000 (0.7%) over 10 years. It tells how many cases would be prevented if the exposure were removed. The relative risk (40/5 = 8) is a ratio, not an attributable risk.", "d": "Attributable risk = incidence in exposed minus incidence in unexposed: (40/5000) − (5/5000) = 0.008 − 0.001 = 0.007 = 7 per 1,000", "t": "Ratio-vs-difference trap — reporting relative risk when attributable risk is asked", "f": "Attributable risk = I_e − I_u (absolute excess); relative risk = I_e ÷ I_u; population attributable risk adds prevalence weighting.", "r": "Attributable risk = incidence in exposed − incidence in unexposed; relative risk = ratio of the two incidences; PAR% = (I_total − I_u)/I_total × 100.", "x": [["B) 8-fold", "8-fold is the relative risk (40/5), a ratio — not the absolute excess risk the question asks for."], ["C) 40 cases", "40 cases is a raw count in the exposed group; measures of association need denominators and comparison."], ["D) 0.9%", "0.9% is close to the unexposed incidence (0.1%) plus something, not the correct computed risk difference of 0.7%."]]}, {"n": 137, "s": "A 40-year-old presents with a chronic cough lasting 3 weeks. In Pakistan's national TB programme (DOTS), which of the following is the recommended first investigation for suspected pulmonary tuberculosis?", "o": [["A", "Sputum smear microscopy for acid-fast bacilli (two sputum specimens)"], ["B", "Chest X-ray alone"], ["C", "CT scan of the chest"], ["D", "GeneXpert in every suspected case at first visit"]], "c": ["A)", "Sputum smear microscopy for acid-fast bacilli (two sputum specimens)"], "co": "Public health — TB diagnosis under national programme", "ct": "Recall (programme algorithm)", "w": "The national TB programme uses symptom screening (cough ≥2–3 weeks) and sputum smear microscopy — two specimens — as the first diagnostic step in adults with presumptive pulmonary TB. Chest X-ray supports diagnosis, especially for smear-negative disease, but smear microscopy is the programme's primary confirmatory tool. GeneXpert (CBNAAT) is recommended for high-risk groups (PLHIV, contacts of MDR-TB, children, extrapulmonary suspicion) and for rifampicin resistance detection, not as routine first-line testing for every suspect in basic settings.", "d": "Under the national TB programme, sputum smear microscopy (2 specimens) is the initial confirmatory test for pulmonary TB in symptomatic adults; GeneXpert is prioritised for high-risk groups and MDR suspects", "t": "High-tech reflex — defaulting to GeneXpert for everyone, ignoring the programme's smear-first algorithm", "f": "Presumptive PTB: 2 sputum smears first (programme norm); GeneXpert for PLHIV, child contacts, MDR suspects; CXR supports smear-negative cases.", "r": "Presumptive TB (cough ≥2–3 weeks ± weight loss, fever, night sweats): sputum smear microscopy ×2; GeneXpert for high-risk groups; treat with category-based DOTS under direct observation; notify all cases.", "x": [["B) Chest X-ray alone", "CXR is supportive and helps diagnose smear-negative disease, but the programme's first confirmatory test is sputum smear microscopy."], ["C) CT scan of the chest", "CT is not part of the basic programme algorithm for TB suspects; it is reserved for complicated/uncertain cases."], ["D) GeneXpert in every suspected case at first visit", "GeneXpert is targeted to high-risk/MDR-suspect groups, not routine first-line testing of every presumptive case in programme settings."]]}, {"n": 138, "s": "In an epidemiological study, cases of hepatitis C are compared with matched controls without hepatitis C, and both groups are asked about past blood transfusions. Which study design is this, and what measure of association is computed?", "o": [["A", "Case-control study; odds ratio"], ["B", "Cohort study; relative risk"], ["C", "Cross-sectional study; prevalence ratio"], ["D", "Randomised trial; risk difference"]], "c": ["A)", "Case-control study; odds ratio"], "co": "Epidemiology — study designs and measures", "ct": "Recall (design identification)", "w": "A case-control study selects people by disease status (cases with hepatitis C, controls without), then looks backward at exposures (blood transfusion). Because incidence cannot be measured directly, the measure of association is the odds ratio — the odds of exposure in cases divided by the odds of exposure in controls. It approximates the relative risk when the disease is rare. Cohort studies measure relative risk; cross-sectional studies measure prevalence.", "d": "Cases (disease) compared with controls (no disease) with retrospective exposure ascertainment = case-control design; the measure is the odds ratio", "t": "Design-blur trap — calling a backward-looking case-control study a cohort because both involve comparison groups", "f": "Identify design by sampling (by disease = case-control → OR; by exposure = cohort → RR; at one time = cross-sectional → prevalence).", "r": "Case-control: select on disease, assess exposure retrospectively, compute OR; cohort: select on exposure, follow for disease, compute RR/AR; cross-sectional: measure exposure and disease simultaneously, compute prevalence.", "x": [["B) Cohort study; relative risk", "A cohort study follows exposed and unexposed forward in time; this study selects by disease and looks back — it is case-control."], ["C) Cross-sectional study; prevalence ratio", "Cross-sectional surveys measure both factors at one point in time and compute prevalence, not exposure recall by disease status."], ["D) Randomised trial; risk difference", "A randomised trial assigns the exposure; exposure here is historical transfusion, not assigned — and it is not a trial."]]}, {"n": 139, "s": "A district health officer must choose between two vaccination campaigns for hepatitis B: one costs 8 million PKR and prevents 400 infections; the other costs 4 million PKR and prevents 150 infections. Which campaign is more cost-effective, and what is the metric?", "o": [["A", "First campaign: 20,000 PKR per infection prevented (more cost-effective)"], ["B", "Second campaign: 26,667 PKR per infection prevented (more cost-effective)"], ["C", "First campaign: 50 infections per million PKR (more cost-effective)"], ["D", "They are equally cost-effective"]], "c": ["A)", "First campaign: 20,000 PKR per infection prevented (more cost-effective)"], "co": "Health economics — cost-effectiveness analysis", "ct": "Analysis/synthesis (computing and comparing cost per outcome)", "w": "Cost-effectiveness analysis compares the cost per unit of health outcome achieved. Campaign 1: 8,000,000 ÷ 400 = 20,000 PKR per infection prevented. Campaign 2: 4,000,000 ÷ 150 = 26,667 PKR per infection prevented. The first campaign is more cost-effective (lower cost per outcome). The alternative metric (infections per million PKR: first = 50, second = 37.5) also favours the first, but the standard CEA metric is cost per outcome.", "d": "Cost-effectiveness = cost ÷ health outcome: first = 8M/400 = 20,000 PKR per infection prevented; second = 4M/150 = 26,667 PKR per prevented infection — the first is cheaper per unit of benefit", "t": "Budget-illusion trap — assuming the cheaper total spend is automatically the better buy, ignoring cost per outcome achieved", "f": "CEA compares cost ÷ outcome, not total budgets; always calculate cost per unit of health benefit before choosing.", "r": "Cost-effectiveness = cost ÷ effectiveness (cost per case prevented, per QALY/DALY, per life saved); select the option with the lowest cost per unit of outcome when effectiveness is measured in the same units; consider budget impact separately.", "x": [["B) Second campaign: 26,667 PKR per infection prevented (more cost-effective)", "26,667 PKR per prevented infection (second campaign) is actually the LESS cost-effective option — higher cost per outcome."], ["C) First campaign: 50 infections per million PKR (more cost-effective)", "50 infections per million PKR correctly describes the first campaign but is the inverse framing; the conventional comparator is cost per outcome, and this option mislabels which is more cost-effective."], ["D) They are equally cost-effective", "The two campaigns differ: 20,000 vs 26,667 PKR per prevented infection, so they are not equivalent."]]}, {"n": 140, "s": "During an autopsy, the forensic pathologist orders a vitreous humour sample for biochemical analysis. Which is the most important advantage of vitreous humour over blood for postmortem biochemistry?", "o": [["A", "It is less affected by postmortem diffusion and haemolysis, and remains stable longer"], ["B", "It can confirm the exact time of death to the minute"], ["C", "It always contains the same electrolyte concentrations as antemortem blood"], ["D", "It is the only fluid that detects alcohol use"]], "c": ["A)", "It is less affected by postmortem diffusion and haemolysis, and remains stable longer"], "co": "Forensic medicine — vitreous humour in postmortem biochemistry", "ct": "Recall (specimen choice rationale)", "w": "The vitreous humour is sequestered behind the lens, away from the viscera, so it is relatively protected from postmortem decomposition, diffusion, and haemolysis — it remains stable for longer than blood. It is valuable for postmortem glucose (diabetic ketoacidosis/suspected hypoglycaemia), urea/creatinine (renal failure), and electrolytes. Potassium rises predictably after death and has been studied as a time-since-death marker but gives only a rough estimate, never a precise minute. Alcohol can be measured in blood, urine, and vitreous alike.", "d": "Vitreous is anatomically isolated, so it resists postmortem biochemical change/haemolysis and is the preferred fluid for glucose, potassium, urea/creatinine, and electrolyte estimation", "t": "Overprecision trap — expecting an exact time-of-death clock from a biological estimation", "f": "Vitreous: postmortem glucose/urea/electrolytes; potassium trend ≈ rough PMI estimate only; caution in infants and burns.", "r": "Vitreous humour: preferred for biochemical analysis due to isolation and stability; potassium rises ~0.14–0.17 mmol/L/h after death (approximate PMI, wide error); glucose/urea useful but interpret with caution.", "x": [["B) It can confirm the exact time of death to the minute", "No postmortem biochemical test gives a precise time of death; vitreous potassium gives only an approximate range."], ["C) It always contains the same electrolyte concentrations as antemortem blood", "Vitreous electrolytes shift after death (potassium rises, others change); they do not equal antemortem blood values exactly."], ["D) It is the only fluid that detects alcohol use", "Alcohol is reliably measured in blood and urine too; vitreous is not the only fluid for it."]]}, {"n": 141, "s": "A body is found with multiple incised wounds on the forearms, defence-type injuries on the palms and dorsum of the hands, and a stab wound to the left chest. Which wound pattern most strongly indicates homicide rather than suicide?", "o": [["A", "Defence (protective) wounds on the forearms and hands"], ["B", "Multiple superficial tentative cuts on the wrists"], ["C", "Injuries in accessible, non-lethal sites only"], ["D", "A single stab wound to the chest through clothing"]], "c": ["A)", "Defence (protective) wounds on the forearms and hands"], "co": "Forensic medicine — wound interpretation: homicide vs suicide", "ct": "Analysis/synthesis (wound pattern interpretation)", "w": "Defence/protective wounds — cuts or bruises on the forearms, palms, and dorsum of hands from grabbing or warding off a weapon — strongly indicate an assault by another person, i.e., homicide. Suicide patterns show tentative (hesitation) cuts, usually parallel superficial incisions at accessible sites (wrists, neck), and wounds that are self-inflictible. A chest stab through clothing can occur in homicide or suicide (though self-inflicted stabbing through clothing is uncommon and each case is assessed with scene and weapon context).", "d": "Defence wounds (forearm/hand injuries from warding off an attacker) are a strong indicator of homicide; suicidal wounds are typically tentative, parallel, on accessible sites, with lethal injuries compatible with self-infliction", "t": "Overreading trap — calling hesitation cuts defence wounds or vice versa; pattern + scene + autopsy must be weighed together", "f": "Defence wounds = homicide indicator; tentative parallel cuts = suicide; document wound distribution, clothing damage, and weapon access.", "r": "Homicide indicators: defence wounds, multiple lethal injuries, wounds in inaccessible sites, scene disruption, missing weapon; suicide indicators: tentative cuts, self-inflictible sites, weapon at scene, no defence wounds; always interpret with scene and autopsy.", "x": [["B) Multiple superficial tentative cuts on the wrists", "Multiple superficial tentative cuts at the wrists are the classic suicidal hesitation pattern, not a homicide indicator."], ["C) Injuries in accessible, non-lethal sites only", "Injuries restricted to accessible, non-lethal sites are more consistent with suicide; homicidal attacks often include defence wounds and lethal-area wounds."], ["D) A single stab wound to the chest through clothing", "A single chest stab could be either; without defence wounds or other indicators, it is not the strongest homicide marker — defence wounds are."]]}, {"n": 142, "s": "In Pakistan, a doctor receives a court summons to give an opinion in a criminal case involving bodily injury. Which role is the doctor now performing, and which law governs the doctor's duty to report and testify truthfully?", "o": [["A", "Expert witness; governed by Qanun-e-Shahadat and the Criminal Procedure Code"], ["B", "Investigating officer; governed by the Police Rules"], ["C", "Defence counsel; governed by the Bar Council"], ["D", "Medico-legal officer in a private capacity; governed by the Medical Association"]], "c": ["A)", "Expert witness; governed by Qanun-e-Shahadat and the Criminal Procedure Code"], "co": "Forensic medicine — medical expert evidence in court", "ct": "Recall (legal framework)", "w": "When a doctor provides a medical opinion in a criminal case (nature/severity of injury, cause of death, age estimation), the doctor acts as an expert witness (or medical witness). The Qanun-e-Shahadat Order 1984 governs the admissibility of evidence and expert opinions; the Criminal Procedure Code governs how medico-legal examinations, reports, and court appearances proceed. The doctor is not an investigating officer (that is police) nor counsel. Professional medical bodies set ethics but do not govern courtroom procedure.", "d": "A doctor giving medical opinion in court is an expert witness; evidence law (Qanun-e-Shahadat Order 1984) and criminal procedure govern competence, oath, and truthful testimony", "t": "Role-confusion trap — casting the medical witness as an investigator when the doctor's duty is expert opinion, not investigation", "f": "Court appearance for medical opinion = expert witness; Qanun-e-Shahadat + CrPC govern; truthfulness is a legal and ethical duty.", "r": "Medical expert witness: gives opinion on injury/cause of death/age under Qanun-e-Shahadat (1984); medico-legal reports (MLCs) are prepared under CrPC guidance; duty of honesty and confidentiality boundaries apply; contempt/penalty for false evidence.", "x": [["B) Investigating officer; governed by the Police Rules", "An investigating officer is a police function; the doctor's role is examination and expert opinion, not investigation."], ["C) Defence counsel; governed by the Bar Council", "Defence counsel is a lawyer's role; the doctor does not represent a party when testifying as a witness."], ["D) Medico-legal officer in a private capacity; governed by the Medical Association", "The doctor acts in a medico-legal capacity under statutory law (evidence and procedure codes), not as a private individual bound only by association ethics."]]}, {"n": 143, "s": "A forensic examination of skeletal remains requires estimation of age. Which of the following is the MOST reliable single indicator for age estimation in a young adult skeleton?", "o": [["A", "Eruption of the third molars"], ["B", "Fusion of the medial end of the clavicle"], ["C", "Cranial suture closure"], ["D", "Pubic symphysis morphology"]], "c": ["B)", "Fusion of the medial end of the clavicle"], "co": "Forensic medicine — skeletal age estimation", "ct": "Recall (reliability of age indicators)", "w": "Age estimation from skeletal remains uses multiple indicators. Medial clavicular epiphyseal fusion (usually complete by ~25 years) is the most reliable marker for late adolescence / young adulthood — the window where other indicators (teeth, long-bone growth) have already closed and cranial sutures are too variable. Third molar eruption is highly variable (17–25 years) and influenced by impaction; cranial suture closure varies widely with genetics/environment; pubic symphysis morphology is better for older adults (symphyseal face changes with age).", "d": "The medial clavicular epiphysis fuses at ~18–25 years — the most reliable indicator across the young-adult age range; third molars erupt variably in the late teens, and cranial sutures are too variable", "t": "Over-preciseness trap — quoting a single 'eruption age' for third molars as definitive when clavicular fusion is the better young-adult indicator", "f": "Young adult skeleton: medial clavicle fusion is the key age marker (~25 y); combine dental, epiphyseal, and symphyseal methods for a range.", "r": "Age indicators by life stage: fetal/child — dental development and long-bone length; adolescent — epiphyseal fusion sequence; young adult — medial clavicular epiphysis (18–25 y); older adult — pubic symphysis and auricular surface changes; give age RANGES, never single years.", "x": [["A) Eruption of the third molars", "Third molar eruption is variable and influenced by impaction/race; it is supportive, not the most reliable single young-adult indicator."], ["C) Cranial suture closure", "Cranial suture closure is too genetically and environmentally variable to be a reliable single age estimator."], ["D) Pubic symphysis morphology", "Pubic symphysis morphology becomes most useful after ~25–30 years of age; before that, epiphyseal fusion is stronger."]]}, {"n": 144, "s": "A melanoma is reported with a Breslow thickness of 1.5 mm. Approximately what 5-year survival does this correspond to?", "o": [["A", "About 50%"], ["B", "Greater than 95%"], ["C", "About 75%"], ["D", "About 90%"]], "c": ["D)", "About 90%"], "co": "Melanoma prognosis — Breslow thickness strata", "ct": "Recall", "w": "Breslow thickness drives melanoma survival: <1 mm has >95%, 1-2 mm about 90%, 2-4 mm about 75% and >4 mm about 50% 5-year survival.", "d": "The stem fixes Breslow at 1.5 mm — squarely in the 1-2 mm band (about 90%).", "t": "Number-band mapping — 1-2 mm is the 90% tier; memorise the four survival bands.", "f": "Breslow survival: <1 mm >95%; 1-2 mm 90%; 2-4 mm 75%; >4 mm ~50%.", "r": "Breslow thickness drives melanoma survival: <1 mm has >95%, 1-2 mm about 90%, 2-4 mm about 75% and >4 mm about 50% 5-year survival.", "x": [["A) About 50%", "About 50% corresponds to >4 mm Breslow thickness."], ["B) Greater than 95%", "Greater than 95% applies to lesions thinner than 1 mm."], ["C) About 75%", "About 75% belongs to the 2-4 mm group."]]}, {"n": 145, "s": "A 24-year-old man is brought in after a motorbike accident. He is hypotensive with distended neck veins, tracheal deviation to the left, and absent breath sounds on the right. What is the most appropriate immediate action?", "o": [["A", "Chest X-ray to confirm before treatment"], ["B", "Immediate needle decompression of the right chest"], ["C", "Oxygen and observation"], ["D", "Urgent CT chest"]], "c": ["B)", "Immediate needle decompression of the right chest"], "co": "Tension pneumothorax — decompress before imaging", "ct": "Interpretation", "w": "Hypotension, distended neck veins, and tracheal deviation with absent unilateral breath sounds = tension pneumothorax; needle decompression comes before any imaging.", "d": "Shock + JVP + tracheal deviation + absent breath sounds is the exact tension cluster; the source says treat before CXR.", "t": "The 'confirm with CXR first' reflex is the trap — the unstable chest is an action question, not an imaging question.", "f": "Tension pneumothorax: decompress now, chest tube next; never wait for the CXR.", "r": "Hypotension, distended neck veins, and tracheal deviation with absent unilateral breath sounds = tension pneumothorax; needle decompression comes before any imaging.", "x": [["A) Chest X-ray to confirm before treatment", "Tension pneumothorax is a clinical diagnosis; waiting for imaging is the named fatal miss."], ["C) Oxygen and observation", "Obstructive shock from tension pneumothorax needs decompression, not observation."], ["D) Urgent CT chest", "Imaging delays the decompression that the clinical signs already mandate."]]}, {"n": 146, "s": "A malnourished chronic alcoholic presents after a binge with abdominal pain, a high anion-gap metabolic acidosis, elevated lactate, and ketonuria, but a normal blood glucose. Which diagnosis fits best?", "o": [["A", "Alcoholic ketoacidosis"], ["B", "Diabetic ketoacidosis"], ["C", "Lactic acidosis only"], ["D", "Salicylate overdose"]], "c": ["A)", "Alcoholic ketoacidosis"], "co": "Alcoholic ketoacidosis — high AG acidosis, ketones + lactate, euglycemic", "ct": "Interpretation", "w": "Alcoholic ketoacidosis occurs after binge drinking in malnourished patients: ethanol metabolism generates NADH, promoting reduction of pyruvate to lactate and of acetoacetate to beta-hydroxybutyrate, producing a high anion-gap acidosis with ketonuria and elevated lactate but a normal or low glucose (unlike DKA, which is hyperglycemic). Treatment is IV dextrose and thiamine.", "d": "Alcoholic + high AG acidosis + ketones + elevated lactate + NORMAL glucose = alcoholic ketoacidosis", "t": "Clinical Mimic — alcoholic ketoacidosis (euglycemic) vs DKA (hyperglycemic)", "f": "Alcoholic + high AG acidosis + ketones/lactate + normal glucose = alcoholic ketoacidosis", "r": "Alcoholic ketoacidosis: high AG acidosis + ketones + lactate + NORMAL glucose (vs DKA hyperglycemia)", "x": [["B) Diabetic ketoacidosis", "DKA is hyperglycemic; this patient is euglycemic."], ["C) Lactic acidosis only", "Lactate alone does not explain the ketonuria."], ["D) Salicylate overdose", "Salicylate causes high AG with a respiratory alkalosis component."]]}, {"n": 147, "s": "A 24-year-old woman has hemoptysis, arthralgias, oral ulcers, hematuria with RBC casts, and proteinuria. Complement C3/C4 are low and anti-dsDNA is positive. Which condition is most consistent?", "o": [["A", "Goodpasture syndrome"], ["B", "Granulomatosis with polyangiitis"], ["C", "Systemic lupus erythematosus with nephritis and pulmonary involvement"], ["D", "Microscopic polyangiitis"]], "c": ["C)", "Systemic lupus erythematosus with nephritis and pulmonary involvement"], "co": "SLE pulmonary-renal — serology", "ct": "Interpretation", "w": "SLE pulmonary-renal disease is immune-complex driven with low complement and anti-dsDNA, plus systemic lupus clues (arthralgias, oral ulcers) — the source's serology table.", "d": "Low C3/C4 + anti-dsDNA + systemic lupus features is the SLE-first serology cluster from the source table.", "t": "The trap is defaulting to ANCA disease whenever lungs and kidneys are both involved; the serology pattern redirects to SLE.", "f": "Hemoptysis + nephritis + low complement/anti-dsDNA = SLE pulmonary-renal disease, not ANCA vasculitis.", "r": "SLE pulmonary-renal disease is immune-complex driven with low complement and anti-dsDNA, plus systemic lupus clues (arthralgias, oral ulcers) — the source's serology table.", "x": [["A) Goodpasture syndrome", "Goodpasture is anti-GBM positive; this patient's low complement and anti-dsDNA point to SLE."], ["B) Granulomatosis with polyangiitis", "GPA is c-ANCA/PR3 with ENT disease; lupus serology does not fit."], ["D) Microscopic polyangiitis", "MPA is p-ANCA/MPO and lacks the lupus systemic features."]]}, {"n": 148, "s": "A 40-year-old man on anti-tuberculous therapy for 3 weeks develops painful joints with a raised serum uric acid. Which drug is responsible?", "o": [["A", "Isoniazid"], ["B", "Rifampicin"], ["C", "Streptomycin"], ["D", "Pyrazinamide"]], "c": ["D)", "Pyrazinamide"], "co": "ATT joint pain — pyrazinamide toxicity", "ct": "Interpretation", "w": "Pyrazinamide causes hyperuricemia and gout-like joint pain; the source matches this symptom explicitly to pyrazinamide.", "d": "Joint pain at 3 weeks on ATT is the exact symptom-to-drug stem; the serum urate elevation seals it.", "t": "INH is the reflex 'neuropathy' answer — the source warns pyrYZINAMIDE, not INH, owns the joints.", "f": "Joint pain/hyperuricemia on ATT = pyrazinamide; neuropathy = INH; vision = ethambutol.", "r": "Pyrazinamide causes hyperuricemia and gout-like joint pain; the source matches this symptom explicitly to pyrazinamide.", "x": [["A) Isoniazid", "INH causes peripheral neuropathy (prevented with pyridoxine), not hyperuricemia."], ["B) Rifampicin", "Rifampicin causes orange secretions, hepatitis, and drug interactions — not gout-like joint pain."], ["C) Streptomycin", "Aminoglycoside toxicity is ototoxicity/nephrotoxicity, not hyperuricemic joint pain."]]}, {"n": 149, "s": "A 30-year-old woman with pyloric stenosis has repeated vomiting. ABG: pH 7.51, HCO3 42 mmol/L, PaCO2 52 mmHg. What is the best interpretation?", "o": [["A", "Respiratory acidosis with metabolic compensation"], ["B", "Metabolic alkalosis with appropriate respiratory compensation"], ["C", "Mixed respiratory and metabolic alkalosis"], ["D", "Metabolic alkalosis without compensation"]], "c": ["B)", "Metabolic alkalosis with appropriate respiratory compensation"], "co": "Vomiting — metabolic alkalosis with respiratory compensation", "ct": "Interpretation", "w": "Vomiting/pyloric stenosis raises HCO3 (metabolic alkalosis); PaCO2 rises as respiratory compensation, so calling the high CO2 primary is wrong.", "d": "Repeated vomiting + high HCO3 + high PaCO2 with high pH is the source's exact metabolic-alkalosis-with-compensation stem.", "t": "The trap is reading high PaCO2 as respiratory acidosis; the pH and the vomiting history decode it.", "f": "Vomiting + high pH + high HCO3 = metabolic alkalosis; the high PaCO2 is compensation, not a second disorder.", "r": "Vomiting/pyloric stenosis raises HCO3 (metabolic alkalosis); PaCO2 rises as respiratory compensation, so calling the high CO2 primary is wrong.", "x": [["A) Respiratory acidosis with metabolic compensation", "High PaCO2 here is the compensating response to a primary high-HCO3 state, not a primary respiratory problem."], ["C) Mixed respiratory and metabolic alkalosis", "The PaCO2 is high, which is the opposite direction of an alkalotic respiratory process."], ["D) Metabolic alkalosis without compensation", "The CO2 has risen in response to the high HCO3 — that is compensation, not its absence."]]}, {"n": 150, "s": "A 40-year-old fair-skinned woman has persistent erythema and papules over the central face with flushing after hot drinks. She has never had comedones. Which diagnosis fits best?", "o": [["A", "Perioral dermatitis"], ["B", "Atopic dermatitis"], ["C", "Allergic contact dermatitis"], ["D", "Rosacea"]], "c": ["D)", "Rosacea"], "co": "Rosacea — central-face erythema/papules, flushing, no comedones", "ct": "Interpretation", "w": "Rosacea presents with central facial flushing, erythema and papules in middle-aged fair-skinned patients; the absence of comedones is the key discriminator from acne vulgaris.", "d": "\"Central face + flushing + never had comedones\" is the rosacea template.", "t": "Comedone gate — no comedones separates rosacea from acne vulgaris.", "f": "Rosacea: central-face flushing/papules, no comedones; rhinophyma is the phymatous end.", "r": "Rosacea presents with central facial flushing, erythema and papules in middle-aged fair-skinned patients; the absence of comedones is the key discriminator from acne vulgaris.", "x": [["A) Perioral dermatitis", "Perioral dermatitis clusters small papules around the mouth and often spares the nasal-forehead axis."], ["B) Atopic dermatitis", "Atopic dermatitis is eczematous with pruritus, distributed flexurally, not central-face flushing."], ["C) Allergic contact dermatitis", "Contact dermatitis is a geometric, contact-site eruption, not a fixed central-face pattern."]]}, {"n": 151, "s": "A 30-year-old hypertensive woman (labetalol on board) has blood pressure 150/95 right arm and 110/70 legs; femoral pulses delayed. Echocardiography shows bicuspid aortic valve with mild stenosis and a discrete posterior juxtaductal narrowing post-ductal gradient 35 mmHg. What is the primary diagnosis and appropriate action?", "o": [["A", "Coarctation of aorta — stent or surgical repair given significant gradient"], ["B", "Essential hypertension — intensify antihypertensives"], ["C", "Chronic renal artery stenosis — angioplasty"], ["D", "Primary hyperaldosteronism — spironolactone"]], "c": ["A)", "Coarctation of aorta — stent or surgical repair given significant gradient"], "co": "Adult coarctation: arm-leg BP gradient + bicuspid association → interventional repair", "ct": "Interpretation", "w": "The classic constellation — upper-limb hypertension with delayed/weak femoral pulses, bicuspid valve association and a juxtaductal gradient ≤35 mmHg — identifies adult coarctation, managed by interventional stent (or surgery) to relieve hypertension and prevent rupture/dissection/endo issues.", "d": "Higher arm than leg BP + bicuspid valve and juxtaductal gradient identifies adult coarctation — repaired when gradient >20 mmHg or arm-leg difference >20–30 and hypertension (stent preferred in adults)", "t": "Clinical Mimic — upper-limb hypertension of coarctation mislabelled as essential", "f": "HTN with leg-pulse delay suggests coarctation: measure 4-limb BP + echo; stent repair if significant.", "r": "Adult coarctation with upper>lower BP disparity + cath gradient >20 mmHg → stent/surgical repair, lifelong aortic surveillance (aneurysm/re-coarctation).", "x": [["B) Essential hypertension — intensify antihypertensives", "Leg-gradient physiology (arm > leg BP) makes essential hypertension the wrong label."], ["C) Chronic renal artery stenosis — angioplasty", "Renal artery stenosis would show renovascular imaging abnormalities (bruit/creatinine discordance), not bicuo valve + posterior gradient."], ["D) Primary hyperaldosteronism — spironolactone", "Aldosteronism explains resistant hypertension without femoral-pulse delay or discrete narrowing."]]}, {"n": 152, "s": "A 60-year-old man with severe pneumonia has PaO2 50 mmHg on room air. After 30 minutes on 100% oxygen his PaO2 rises only minimally. What mechanism best explains this pattern?", "o": [["A", "Simple V/Q mismatch"], ["B", "Intrapulmonary shunt through non-ventilated consolidated lung"], ["C", "Diffusion defect alone"], ["D", "Right-to-left cardiac shunt"]], "c": ["B)", "Intrapulmonary shunt through non-ventilated consolidated lung"], "co": "Refractory hypoxemia — shunt physiology", "ct": "Interpretation", "w": "Perfusion continues through non-ventilated consolidated lung, so oxygen cannot correct the hypoxemia — the source pairs 'PaO2 barely improves with 100% O2' with intrapulmonary shunt.", "d": "Failure to correct on 100% oxygen is the discriminator that separates shunt from V/Q mismatch in the source.", "t": "V/Q mismatch is the reflex answer; the source calls out the shunt-versus-mismatch swap as a named trap.", "f": "PaO2 barely rising on 100% O2 = shunt: escalate respiratory support, not 'more oxygen'.", "r": "Perfusion continues through non-ventilated consolidated lung, so oxygen cannot correct the hypoxemia — the source pairs 'PaO2 barely improves with 100% O2' with intrapulmonary shunt.", "x": [["A) Simple V/Q mismatch", "V/Q mismatch improves with oxygen; a shunt barely responds, so near-zero correction points away from simple mismatch."], ["C) Diffusion defect alone", "Diffusion limitation would improve substantially with high FiO2; refractory hypoxemia at 100% oxygen is the shunt signature."], ["D) Right-to-left cardiac shunt", "No congenital heart clue is given; the consolidated pneumonia is the source's shunt mechanism."]]}, {"n": 153, "s": "A 45-year-old man develops sudden pleuritic chest pain and dyspnea 6 days after a long-haul flight. CTPA shows a right pulmonary artery filling defect. BP is 90/60 mmHg with HR 125/min. What is the most appropriate management?", "o": [["A", "Anticoagulation alone with observation"], ["B", "IV fluids and repeat imaging"], ["C", "Urgent inferior vena cava filter placement instead"], ["D", "Systemic thrombolysis if no contraindication"]], "c": ["D)", "Systemic thrombolysis if no contraindication"], "co": "Massive PE — thrombolysis decision", "ct": "Interpretation", "w": "PE with hypotension/shock is massive/high-risk PE and becomes a thrombolysis (reperfusion) question if no contraindication exists.", "d": "BP 90/60 with a CTPA filling defect after long-haul flight is the source's 'BP is the pivot' stem.", "t": "The trap is treating massive PE like stable PE; hemodynamic instability changes anticoagulation into thrombolysis.", "f": "In PE, BP decides: shock = thrombolysis if eligible; stable = anticoagulate.", "r": "PE with hypotension/shock is massive/high-risk PE and becomes a thrombolysis (reperfusion) question if no contraindication exists.", "x": [["A) Anticoagulation alone with observation", "Hypotension defines high-risk/massive PE; anticoagulation alone is insufficient when shock is present."], ["B) IV fluids and repeat imaging", "Massive PE with shock is a reperfusion question; fluid resuscitation does not treat the obstruction."], ["C) Urgent inferior vena cava filter placement instead", "An IVC filter prevents further emboli but does not treat the obstructing clot; the unstable patient needs systemic thrombolysis."]]}, {"n": 154, "s": "A 50-year-old obese man has symmetrical velvety darkening of the axillae and neck. Which underlying condition is most commonly associated with this finding?", "o": [["A", "Adrenal insufficiency"], ["B", "Thyroid carcinoma"], ["C", "Insulin resistance"], ["D", "Coeliac disease"]], "c": ["C)", "Insulin resistance"], "co": "Acanthosis nigricans — insulin resistance is the commonest association", "ct": "Interpretation", "w": "Acanthosis nigricans (velvety hyperpigmentation of flexures) is most commonly a marker of insulin resistance; sudden rapid onset should raise suspicion for a paraneoplastic cause.", "d": "Axillary/neck velvety darkening in an obese adult points to insulin resistance, not an endocrine tumour.", "t": "Marker logic — flexural velvety darkening = insulin resistance; rapid onset flips the thinking to malignancy.", "f": "Acanthosis nigricans = insulin resistance (common); rapid onset → paraneoplastic (gastric adenocarcinoma).", "r": "Acanthosis nigricans (velvety hyperpigmentation of flexures) is most commonly a marker of insulin resistance; sudden rapid onset should raise suspicion for a paraneoplastic cause.", "x": [["A) Adrenal insufficiency", "Adrenal insufficiency gives diffuse hyperpigmentation (mucous membranes, palmar creases), not velvety flexural patches."], ["B) Thyroid carcinoma", "Thyroid carcinoma is not a recognised acanthosis nigricans association."], ["D) Coeliac disease", "Coeliac disease associates with dermatitis herpetiformis, not this finding."]]}, {"n": 155, "s": "A 45-year-old man presents with apparently new type 2 diabetes and seems to require insulin within 1 year despite initial oral therapy. He is not obese. Glutamic acid decarboxylase (GAD) antibodies are positive. What does this indicate?", "o": [["A", "Typical type 2 diabetes"], ["B", "MODY"], ["C", "Latent autoimmune diabetes in adults (LADA)"], ["D", "Type 3c (pancreatogenic) diabetes"]], "c": ["C)", "Latent autoimmune diabetes in adults (LADA)"], "co": "LADA — adult T2 phenotype but autoimmune (GAD+), progresses to insulin", "ct": "Interpretation", "w": "LADA is a slow-progressing autoimmune diabetes presenting in adulthood with an initially type 2-like (often non-obese) phenotype but positive islet autoantibodies (GAD65). It is distinct from MODY (monogenic, antibody-negative) and type 2 (antibody-negative). Recognising LADA matters because these patients ultimately need insulin and may not respond durably to oral agents.", "d": "Adult 'T2DM' phenotype + GAD antibodies + early insulin requirement = LADA (slow autoimmune)", "t": "Classification trap — LADA (autoimmune, GAD+) vs type 2 (antibody-negative) vs MODY", "f": "Adult 'T2DM' + GAD antibodies + early insulin need = LADA (not MODY/type 2)", "r": "LADA: adult-onset autoimmune diabetes (GAD+), T2-like onset, progresses to insulin; not MODY", "x": [["A) Typical type 2 diabetes", "Typical type 2 lacks autoantibodies and rarely needs insulin so soon without obesity."], ["B) MODY", "MODY is monogenic and antibody-negative with dominant family history."], ["D) Type 3c (pancreatogenic) diabetes", "Type 3c follows pancreatic disease and shows exocrine insufficiency."]]}, {"n": 156, "s": "A 50-year-old man with 12 years of type 2 diabetes has visual blurring and floaters. Fundoscopy shows neovascularisation of the disc and vitreous haemorrhage. What is the most urgent intervention?", "o": [["A", "Topical antibiotics"], ["B", "Cataract surgery"], ["C", "Observation and repeat in 6 months"], ["D", "Panretinal photocoagulation (laser) + urgent ophthalmology review"]], "c": ["D)", "Panretinal photocoagulation (laser) + urgent ophthalmology review"], "co": "Diabetic retinopathy — proliferative stage: neovascularisation → panretinal laser", "ct": "Analysis/synthesis", "w": "Diabetic retinopathy progresses from background (microaneurysms, dots/blots) to pre-proliferative to proliferative (neovascularisation, vitreous haemorrhage, tractional detachment). Proliferative disease requires urgent panretinal photocoagulation to reduce vision loss risk; anti-VEGF and vitrectomy are adjuncts. Annual screening of all diabetics detects earlier stages.", "d": "Neovascularisation/vitreous haemorrhage = proliferative diabetic retinopathy → panretinal laser", "t": "One-word discriminator — neovascularisation = proliferative → panretinal laser", "f": "Neovascularisation/vitreous bleed = proliferative retinopathy → urgent panretinal laser", "r": "Proliferative diabetic retinopathy: neovascularisation → panretinal photocoagulation; screen annually", "x": [["A) Topical antibiotics", "Antibiotics do not treat neovascular retinopathy."], ["B) Cataract surgery", "Cataract surgery addresses lens opacity, not proliferative retinopathy."], ["C) Observation and repeat in 6 months", "Observation risks irreversible blindness from tractional detachment."]]}, {"n": 157, "s": "Which of the following is the most common cause of acute viral hepatitis in children?", "o": [["A", "Hepatitis B"], ["B", "Hepatitis A"], ["C", "Hepatitis C"], ["D", "Hepatitis D"]], "c": ["B)", "Hepatitis A"], "co": "Hepatitis A — most common acute hepatitis in children", "ct": "Recall", "w": "Hepatitis A, transmitted fecal-orally, is the most common cause of acute viral hepatitis in children. It is usually self-limited with no chronic carrier state.", "d": "Hepatitis A is the most common cause of acute viral hepatitis in children (fecal-oral spread)", "t": "Overthinking — obvious answer (Hep A) second-guessed toward B/C", "f": "Acute hepatitis in a child = Hep A (fecal-oral, self-limited, no chronicity)", "r": "Hepatitis A = most common acute viral hepatitis in children, fecal-oral, no carrier state", "x": [["A) Hepatitis B", "Hepatitis B is less common in children and is blood/vertical transmission."], ["C) Hepatitis C", "Hepatitis C is blood-borne and uncommon in children."], ["D) Hepatitis D", "Hepatitis D requires co-infection with hepatitis B and is rare."]]}, {"n": 158, "s": "A patient has a normal anion-gap metabolic acidosis. The urine anion gap is positive (urine Na+K − Cl is positive), indicating low urinary ammonium. What is the most likely diagnosis?", "o": [["A", "Renal tubular acidosis (impaired NH4+ excretion)"], ["B", "Diarrhea"], ["C", "Salicylate overdose"], ["D", "Methanol ingestion"]], "c": ["A)", "Renal tubular acidosis (impaired NH4+ excretion)"], "co": "Normal AG acidosis — positive urine anion gap = RTA (low NH4 excretion); negative = diarrhea", "ct": "Analysis/synthesis", "w": "In normal anion-gap (hyperchloraemic) metabolic acidosis, the urine anion gap (U_Na + U_K − U_Cl) distinguishes renal from extra-renal causes. A positive value means the kidney is NOT excreting ammonium (RTA); a negative value (high NH4) means the kidney is appropriately acidifying (extra-renal cause like diarrhea). Diarrhea produces a negative urine anion gap.", "d": "Normal AG acidosis: POSITIVE urine anion gap = RTA; NEGATIVE (high NH4) = GI/diarrhea loss", "t": "One-word discriminator — urine anion gap (positive = RTA, negative = GI loss)", "f": "Normal AG acidosis: +urine anion gap = RTA; −urine anion gap = diarrhea/GI loss", "r": "Urine anion gap: positive = RTA (low NH4); negative = diarrhea/GI bicarbonate loss", "x": [["B) Diarrhea", "Diarrhea yields a NEGATIVE urine anion gap (high urinary NH4)."], ["C) Salicylate overdose", "Salicylate causes high AG (and respiratory) acidosis."], ["D) Methanol ingestion", "Methanol causes high AG acidosis with osmolal gap."]]}, {"n": 159, "s": "A 30-year-old man with a cervical spinal cord injury suddenly develops a severe headache, sweating, and a blood pressure of 200/110 mmHg. The trigger is most commonly:", "o": [["A", "Lower limb fracture"], ["B", "Hypoglycaemia"], ["C", "Pulmonary embolism"], ["D", "Bladder distension (full catheter bag / blocked catheter)"]], "c": ["D)", "Bladder distension (full catheter bag / blocked catheter)"], "co": "Autonomic dysreflexia — bladder distension is the most common trigger", "ct": "Analysis/synthesis", "w": "Autonomic dysreflexia occurs in spinal cord lesions above T6, with a noxious stimulus below the lesion (most commonly bladder distension from a full or blocked catheter, or bowel impaction) causing massive sympathetic discharge: severe hypertension, headache, sweating, bradycardia. It is a medical emergency; relieve the trigger (catheterise/drain) and lower BP. Bladder/bowel triggers dominate.", "d": "SCI above T6 + sudden hypertension/headache/sweating = autonomic dysreflexia; bladder trigger", "t": "One-word discriminator — bladder distension = most common dysreflexia trigger", "f": "Autonomic dysreflexia (SCI above T6) → bladder distension is the common trigger", "r": "Autonomic dysreflexia: SCI above T6 + HTN/headache/sweating; bladder distension is top trigger", "x": [["A) Lower limb fracture", "Limb fracture is an unusual trigger; bladder/bowel are common."], ["B) Hypoglycaemia", "Hypoglycaemia does not cause this hypertensive pattern."], ["C) Pulmonary embolism", "PE causes hypoxia/hypotension, not this sympathetic surge."]]}, {"n": 160, "s": "A patient with primary hyperparathyroidism suddenly develops severe hypercalcaemia (Ca 15 mg/dL) with confusion, abdominal pain, and dehydration. What is the most urgent definitive treatment if medical measures fail?", "o": [["A", "Observation"], ["B", "Urgent parathyroidectomy (after stabilisation)"], ["C", "Long-term bisphosphonate only"], ["D", "Thyroidectomy"]], "c": ["B)", "Urgent parathyroidectomy (after stabilisation)"], "co": "Parathyroid crisis — severe symptomatic hypercalcaemia → urgent parathyroidectomy after stabilisation", "ct": "Analysis/synthesis", "w": "Parathyroid (hypercalcaemic) crisis is a surgical emergency presenting with severe hypercalcaemia and neuropsychiatric, renal, and GI manifestations. Initial management is aggressive intravenous fluids and bisphosphonines/cinacalcet to stabilise, followed by urgent parathyroidectomy of the offending gland(s). Delay risks arrhythmia and coma. It is a parathyroid, not thyroid, operation.", "d": "Symptomatic severe hyperCa from HPT = parathyroid crisis → urgent parathyroidectomy (after resuscitation)", "t": "Severity under-recognition — severe symptomatic hyperCa in HPT = parathyroid crisis (urgent surgery)", "f": "Symptomatic severe hypercalcaemia from HPT = parathyroid crisis → urgent parathyroidectomy", "r": "Parathyroid crisis: severe symptomatic HPT hyperCa → stabilise (fluids/bisphosphonate) then urgent parathyroidectomy", "x": [["A) Observation", "Observation is dangerous in a hypercalcaemic crisis."], ["C) Long-term bisphosphonate only", "Bisphosphonates stabilise but do not remove the diseased gland; surgery is definitive."], ["D) Thyroidectomy", "The parathyroid, not the thyroid, is the source."]]}, {"n": 161, "s": "A 28-year-old man has a painless testicular mass. Tumour markers show an elevated alpha-fetoprotein (AFP) and normal human chorionic gonadotropin (hCG). Which histological category does this favour?", "o": [["A", "Pure seminoma"], ["B", "Leydig cell tumour"], ["C", "Non-seminomatous germ cell tumour"], ["D", "Lymphoma"]], "c": ["C)", "Non-seminomatous germ cell tumour"], "co": "Testicular germ cell tumour — AFP elevated implies non-seminomatous component", "ct": "Analysis/synthesis", "w": "Alpha-fetoprotein is produced only by non-seminomatous germ cell tumours (yolk sac, embryonal, choriocarcinoma, teratoma); a pure seminoma never elevates AFP (hCG may be mildly raised). Thus an elevated AFP mandates classifying as non-seminomatous, which guides orchidectomy plus cisplatin-based chemotherapy and retroperitoneal lymph node dissection.", "d": "Elevated AFP = NON-seminomatous GCT (seminoma has normal AFP; hCG may be raised)", "t": "Classification trap — AFP normal in seminoma; AFP↑ = non-seminomatous", "f": "Elevated AFP = non-seminomatous GCT; pure seminoma has normal AFP", "r": "Testicular GCT: AFP↑ = non-seminoma (seminoma has NORMAL AFP, may raise hCG)", "x": [["A) Pure seminoma", "Pure seminoma has a NORMAL AFP; an elevated AFP excludes pure seminoma."], ["B) Leydig cell tumour", "Leydig cell tumours are sex-cord stromal, not germ cell, and don't raise AFP."], ["D) Lymphoma", "Lymphoma occurs in older men and is bilateral; AFP is not elevated."]]}, {"n": 162, "s": "A 45-year-old man with a history of recurrent urethral discharge and prior catheterisation has a weak stream, terminal dribbling, and a palpable bladder. What is the most likely cause?", "o": [["A", "Overactive bladder"], ["B", "Urethral stricture"], ["C", "Urinary tract infection"], ["D", "Nephrolithiasis"]], "c": ["B)", "Urethral stricture"], "co": "Urethral stricture — obstructive voiding from scarring (catheter/trauma/STD)", "ct": "Interpretation", "w": "Urethral stricture is fibrous narrowing from trauma, instrumentation/catheterisation, or sexually transmitted inflammation (gonococcal/Chlamydia). It causes obstructive voiding (weak stream, straining, terminal dribbling, retention) and a palpable bladder. Overactive bladder causes frequency/urgency; infection causes dysuria. Management is dilation or urethroplasty.", "d": "Weak stream + terminal dribbling + palpable bladder after catheter/STD = urethral stricture", "t": "Clinical Mimic — stricture (obstructive, palpable bladder) vs overactive bladder (urgency)", "f": "Weak stream + palpable bladder after catheter/STD = urethral stricture", "r": "Urethral stricture: obstructive voiding from scarring (catheter/trauma/STD); dilation/urethroplasty", "x": [["A) Overactive bladder", "Overactive bladder presents with urgency/frequency, not weak stream/retention."], ["C) Urinary tract infection", "UTI causes dysuria/frequency, not a weak mechanical stream with retention."], ["D) Nephrolithiasis", "Stones cause colic/haematuria, not a progressive weak stream."]]}, {"n": 163, "s": "A 50-year-old man has severe hypercalcaemia (Ca 17 mg/dL), a hard, fixed neck mass, and a very high PTH. Imaging shows local invasion. What is the diagnosis and surgery?", "o": [["A", "Benign parathyroid adenoma — minimally invasive resection"], ["B", "Parathyroid carcinoma — en bloc resection with ipsilateral thyroid lobe"], ["C", "Medullary thyroid carcinoma"], ["D", "Thyroid adenoma"]], "c": ["B)", "Parathyroid carcinoma — en bloc resection with ipsilateral thyroid lobe"], "co": "Parathyroid carcinoma — hard fixed invasive mass + very high Ca/PTH → en bloc resection", "ct": "Analysis/synthesis", "w": "Parathyroid carcinoma is rare but suggested by a hard, fixed, invasive neck mass with markedly elevated calcium and PTH, often refractory hypercalcaemia. Surgery is en bloc resection of the tumour with the ipsilateral thyroid lobe and clear margins (avoiding tumour violation/fragmentation). It is distinguished from benign adenoma (soft, mobile, MIP) and from medullary thyroid carcinoma (calcitonin). Long-term control hinges on complete initial resection.", "d": "Hard fixed invasive parathyroid mass + severe hyperCa/PTH = carcinoma → en bloc resection", "t": "Clinical Mimic — parathyroid carcinoma (hard/fixed/invasive, very high Ca) vs benign adenoma", "f": "Hard fixed invasive mass + severe hyperCa/PTH = parathyroid carcinoma → en bloc resection", "r": "Parathyroid carcinoma: hard fixed invasive mass + severe hyperCa/PTH → en bloc resection + ipsilateral lobe", "x": [["A) Benign parathyroid adenoma — minimally invasive resection", "A benign adenoma is soft/mobile and treated with MIP, not en bloc for cancer."], ["C) Medullary thyroid carcinoma", "Medullary thyroid carcinoma secretes calcitonin and arises from thyroid C-cells."], ["D) Thyroid adenoma", "A thyroid adenoma does not cause PTH-driven hypercalcaemia."]]}, {"n": 164, "s": "A patient with long-standing CKD on dialysis develops progressively rising PTH and calcium despite medical therapy and is being evaluated for transplant. What is the underlying process?", "o": [["A", "Primary hyperparathyroidism from an adenoma"], ["B", "Tertiary hyperparathyroidism — autonomous parathyroid hyperplasia from CKD"], ["C", "Vitamin D toxicity"], ["D", "Sarcoidosis"]], "c": ["B)", "Tertiary hyperparathyroidism — autonomous parathyroid hyperplasia from CKD"], "co": "Tertiary hyperparathyroidism — CKD-driven parathyroid hyperplasia becomes autonomous", "ct": "Interpretation", "w": "Tertiary hyperparathyroidism develops in chronic kidney disease when longstanding secondary hyperplasia of the parathyroids becomes autonomous, producing excessive PTH and hypercalcaemia despite dialysis/medical therapy. Severe, refractory cases (or before transplant to prevent progression) are treated surgically with subtotal/total parathyroidectomy and autotransplantation. It is distinct from primary HPT (adenoma) and secondary HPT (physiologic response to low Ca).", "d": "CKD + refractory high PTH/high Ca = tertiary HPT (autonomous hyperplasia); surgery if severe", "t": "Clinical Mimic — tertiary (CKD, autonomous hyperplasia) vs primary (adenoma) HPT", "f": "CKD + refractory high PTH/hyperCa = tertiary HPT → subtotal/total parathyroidectomy", "r": "Tertiary HPT: CKD → parathyroid hyperplasia becomes autonomous; surgery if refractory/pre-transplant", "x": [["A) Primary hyperparathyroidism from an adenoma", "Primary HPT is an adenoma, not CKD-driven hyperplasia."], ["C) Vitamin D toxicity", "Vitamin D toxicity causes hypercalcaemia but not high PTH and not in this CKD context."], ["D) Sarcoidosis", "Sarcoidosis causes hypercalcaemia via calcitriol, with low PTH."]]}, {"n": 165, "s": "A 28-year-old woman presents with fever, flank pain, and costovertebral angle tenderness. Urinalysis shows leucocytes and nitrites. What is the most likely causative organism?", "o": [["A", "Staphylococcus aureus"], ["B", "Escherichia coli"], ["C", "Pseudomonas aeruginosa"], ["D", "Candida albicans"]], "c": ["B)", "Escherichia coli"], "co": "Acute pyelonephritis — E. coli is the most common pathogen", "ct": "Recall", "w": "Acute pyelonephritis is usually ascending infection; Escherichia coli (from peri-urethral faecal flora) causes the vast majority of community-acquired cases, followed by other Enterobacteriaceae (Klebsiella, Proteus). Nitrite-positive urine reflects nitrate-reducing organisms like E. coli. S. aureus suggests haematogenous spread; Pseudomonas/Candida suggest catheter/healthcare-associated sources.", "d": "Uncomplicated pyelonephritis/UTI = E. coli (~80-90%) from ascending faecal flora", "t": "One-word discriminator — E. coli most common (ascending faecal flora)", "f": "Pyelonephritis/UTI = E. coli (~80-90%); nitrite-positive", "r": "Acute pyelonephritis: E. coli is the most common pathogen (ascending faecal flora, nitrite+)", "x": [["A) Staphylococcus aureus", "S. aureus implies haematogenous seeding, not typical ascending pyelonephritis."], ["C) Pseudomonas aeruginosa", "Pseudomonas suggests hospital/ catheter-associated infection."], ["D) Candida albicans", "Candida suggests fungal/ catheter-associated infection, not routine pyelonephritis."]]}, {"n": 166, "s": "A 26-year-old man presents with infertility and a 'bag of worms' sensation in the left scrotum that diminishes when supine. What is the most likely finding and association?", "o": [["A", "Right varicocele — normal variant"], ["B", "Hydrocele — transilluminates"], ["C", "Epididymal cyst — separate from testis"], ["D", "Left varicocele — dilated pampiniform plexus; associated with left RCC"]], "c": ["D)", "Left varicocele — dilated pampiniform plexus; associated with left RCC"], "co": "Varicocele — left-sided (venous drainage), infertility, adult right-side suggests RCC", "ct": "Interpretation", "w": "A varicocele is dilation of the pampiniform plexus, usually left-sided because the left gonadal vein drains into the left renal vein at a right angle. It causes a 'bag of worms' that collapses when supine and is a common cause of infertility. A NEW right-sided varicocele in an adult is concerning for renal cell carcinoma (tumour thrombus obstructing the right gonadal vein).", "d": "Left 'bag of worms' scrotal swelling = varicocele; NEW right-sided varicocele suggests RCC", "t": "Clinical Mimic — left varicocele (common) vs new right varicocele (RCC until excluded)", "f": "Left varicocele = benign infertility; NEW right varicocele in adult = RCC", "r": "Varicocele: left common (infertility); new RIGHT-sided in adult = suspect RCC (venous obstruction)", "x": [["A) Right varicocele — normal variant", "Varicoceles are overwhelmingly left-sided; right-sided in adults warrants RCC workup."], ["B) Hydrocele — transilluminates", "Hydrocele transilluminates and is a fluid collection, not a 'bag of worms'."], ["C) Epididymal cyst — separate from testis", "Epididymal cyst is a separate, smooth nodule above the testis."]]}, {"n": 167, "s": "A patient with clinical Cushing syndrome and a normal pituitary MRI is being evaluated before transsphenoidal surgery. Which test helps confirm the source is pituitary (Cushing disease) rather than ectopic ACTH?", "o": [["A", "Bilateral inferior petrosal sinus sampling (BIPSS) showing central:peripheral ACTH gradient"], ["B", "Low-dose dexamethasone suppression test"], ["C", "24-hour urinary free cortisol"], ["D", "Plasma metanephrines"]], "c": ["A)", "Bilateral inferior petrosal sinus sampling (BIPSS) showing central:peripheral ACTH gradient"], "co": "Cushing disease — BIPSS confirms pituitary source before transsphenoidal surgery", "ct": "Analysis/synthesis", "w": "When Cushing syndrome is clinically Cushing disease but the pituitary MRI is normal/inconclusive, bilateral inferior petrosal sinus sampling (BIPSS) is the gold standard to confirm a pituitary source: a central (petrosal):peripheral ACTH ratio >2 (or >3 after CRH) localises ACTH overproduction to the pituitary, justifying transsphenoidal surgery. Ectopic ACTH (e.g., small-cell lung) shows a low gradient. Dexamethasone/UFC are screening, not localising, tests.", "d": "Pituitary MRI normal in Cushing → BIPSS (central:peripheral ACTH gradient) confirms pituitary source", "t": "Classification trap — BIPSS confirms pituitary (Cushing disease) vs ectopic ACTH before TSS", "f": "Normal pituitary MRI in Cushing → BIPSS gradient confirms pituitary source before TSS", "r": "Cushing disease: BIPSS (central:peripheral ACTH gradient) confirms pituitary source before transsphenoidal surgery", "x": [["B) Low-dose dexamethasone suppression test", "Low-dose dexamethasone suppression screens for Cushing, not localises the source."], ["C) 24-hour urinary free cortisol", "24h UFC confirms hypercortisolism, not the pituitary vs ectopic distinction."], ["D) Plasma metanephrines", "Plasma metanephrines screen for phaeochromocytoma, not ACTH source."]]}, {"n": 168, "s": "A 58-year-old smoker presents with painless gross haematuria, left flank pain, and a palpable abdominal mass. CT shows a 9 cm heterogeneous renal mass extending into the renal vein. What is the most likely diagnosis?", "o": [["A", "Transitional cell carcinoma of the renal pelvis"], ["B", "Renal cell carcinoma"], ["C", "Wilms tumour"], ["D", "Angiomyolipoma"]], "c": ["B)", "Renal cell carcinoma"], "co": "Renal cell carcinoma — painless haematuria + flank mass + paraneoplastic, smoking", "ct": "Analysis/synthesis", "w": "Renal cell carcinoma (clear cell) is the most common renal malignancy in adults, classically presenting with painless haematuria, flank pain, and a palpable mass (the triad), often with paraneoplastic syndromes (polycythaemia from EPO, hypercalcaemia, Stauffer syndrome). Smoking is the chief risk factor. It spreads via the renal vein. Treatment is nephrectomy.", "d": "Adult + painless haematuria + flank mass + renal vein extension + smoking = RCC", "t": "Severity under-recognition — painless haematuria in adult = malignancy until excluded", "f": "Adult painless haematuria + flank mass + renal vein = RCC (smoking risk)", "r": "RCC = adult painless haematuria + flank mass + paraneoplastic (polycythaemia); smoking; nephrectomy", "x": [["A) Transitional cell carcinoma of the renal pelvis", "TCC of the renal pelvis causes haematuria but arises from urothelium, not a parenchymal mass with venous extension."], ["C) Wilms tumour", "Wilms tumour occurs in children <5 years, not adults."], ["D) Angiomyolipoma", "Angiomyolipoma is benign, often in tuberous sclerosis, and fat-containing."]]}, {"n": 169, "s": "A 55-year-old uncircumcised man presents with a non-healing ulcerative lesion on the glans penis. Which is the strongest associated risk factor?", "o": [["A", "Poor hygiene / phimosis with HPV infection"], ["B", "Circumcision in infancy"], ["C", "Low-risk sexual behaviour"], ["D", "Diabetes mellitus"]], "c": ["A)", "Poor hygiene / phimosis with HPV infection"], "co": "Penile cancer — HPV + phimosis/poor hygiene; ulcer on glans", "ct": "Interpretation", "w": "Penile squamous cell carcinoma presents as an ulcerated or exophytic lesion on the glans or foreskin. Risk factors are poor hygiene, phimosis (smegma accumulation), and HPV (especially HPV 16). Circumcision in infancy is protective. Inguinal node involvement guides staging and prognosis.", "d": "Glans ulcer in uncircumcised man = penile squamous cell carcinoma (HPV, phimosis risk)", "t": "Clinical Mimic — penile ulcer (cancer) vs chancre (syphilis) vs herpes", "f": "Non-healing glans ulcer + phimosis/HPV risk = penile SCC; infant circumcision protective", "r": "Penile SCC = glans ulcer, HPV + phimosis/poor hygiene risk; infant circumcision protective", "x": [["B) Circumcision in infancy", "Circumcision in infancy is PROTECTIVE, not a risk factor."], ["C) Low-risk sexual behaviour", "Low-risk behaviour reduces, not increases, HPV-related risk."], ["D) Diabetes mellitus", "Diabetes is not a primary risk factor for penile carcinoma."]]}, {"n": 170, "s": "A 62-year-old woman who had an emergency laparotomy for a perforated peptic ulcer 16 months ago now notices a bulge in her midline scar that has slowly enlarged and becomes uncomfortable on lifting. It is reducible and not tender. She is otherwise fit. What is the most appropriate management?", "o": [["A", "Watchful waiting with an abdominal support belt"], ["B", "Elective mesh repair of the incisional hernia"], ["C", "Emergency repair"], ["D", "Weight loss alone before any operative planning"]], "c": ["B)", "Elective mesh repair of the incisional hernia"], "co": "Incisional hernia — indications for elective repair", "ct": "Analysis/synthesis (enlarging symptomatic incisional hernia → elective mesh repair)", "w": "An enlarging, symptomatic incisional hernia in a fit patient merits elective mesh repair, which carries a lower recurrence rate than suture repair; emergency repair is reserved for incarceration or strangulation.", "d": "Enlarging, uncomfortable incisional hernia in a fit patient → elective mesh repair (mesh reduces recurrence)", "t": "Severity under-recognition — dismissing an enlarging hernia as 'just a bulge' risks strangulation", "f": "Incisional hernia + pain/obstruction = emergency; enlarging but reducible = elective mesh repair", "r": "Symptomatic or enlarging incisional hernia → elective repair with mesh", "x": [["A) Watchful waiting with an abdominal support belt", "A: A support belt is a temporising measure, not definitive management for an enlarging symptomatic hernia."], ["C) Emergency repair", "C: There is no evidence of incarceration or strangulation (reducible, not tender) to justify emergency surgery."], ["D) Weight loss alone before any operative planning", "D: Weight loss is adjunctive; delaying surgery on that basis alone is not the most appropriate plan."]]}, {"n": 171, "s": "A 3-year-old child is found to have a large, smooth, unilateral abdominal mass that does not cross the midline. There is no haematuria. What is the most likely diagnosis?", "o": [["A", "Neuroblastoma"], ["B", "Renal cell carcinoma"], ["C", "Hydronephrosis"], ["D", "Wilms tumour (nephroblastoma)"]], "c": ["D)", "Wilms tumour (nephroblastoma)"], "co": "Wilms tumour — pediatric abdominal mass <5 years, unilateral, smooth", "ct": "Interpretation", "w": "Wilms tumour (nephroblastoma) is the most common renal tumour of childhood, presenting before age 5 as a smooth, firm, unilateral abdominal mass that does not cross the midline (unlike neuroblastoma, which is often midline and invasive). Hypertension from renin is common; haematuria is less frequent. Treatment is nephrectomy plus chemotherapy/radiotherapy.", "d": "Child <5 + smooth unilateral abdominal mass (no cross midline) = Wilms tumour", "t": "Clinical Mimic — Wilms (smooth, unilateral, <5y) vs neuroblastoma (midline, invasive)", "f": "Child <5 + smooth unilateral mass = Wilms; neuroblastoma is midline/invasive", "r": "Wilms = nephroblastoma, child <5, smooth unilateral abdominal mass, WT1; nephrectomy + chemo", "x": [["A) Neuroblastoma", "Neuroblastoma is typically midline, invasive, and crosses the midline; often with opsoclonus."], ["B) Renal cell carcinoma", "RCC is an adult tumour."], ["C) Hydronephrosis", "Hydronephrosis is a cystic, fluctuant swelling, not a solid smooth mass."]]}, {"n": 172, "s": "A 60-year-old man with poor hygiene has inability to retract the foreskin over the glans, with no acute pain or swelling. A younger man presents acutely with a retracted foreskin trapped behind the glans with pain and oedema. Which pairing is correct?", "o": [["A", "First = paraphimosis; second = phimosis"], ["B", "First = phimosis; second = paraphimosis"], ["C", "Both are phimosis"], ["D", "Both are paraphimosis"]], "c": ["B)", "First = phimosis; second = paraphimosis"], "co": "Phimosis vs paraphimosis — cannot retract vs trapped retracted foreskin", "ct": "Interpretation", "w": "Phimosis is the inability to retract the foreskin over the glans (often from chronic inflammation/balanitis). Paraphimosis is the acute trapping of a retracted foreskin behind the coronal sulcus, causing oedema and ischaemia — a urological urgency requiring manual reduction (or dorsal slit). The two are opposite problems.", "d": "Phimosis = cannot retract foreskin; paraphimosis = retracted foreskin trapped (acute, needs reduction)", "t": "Opposite — phimosis (cannot retract) vs paraphimosis (trapped retracted)", "f": "Phimosis = cannot retract; paraphimosis = retracted foreskin trapped (urgent reduction)", "r": "Phimosis = tight foreskin (can't retract); paraphimosis = retracted foreskin trapped (urgent)", "x": [["A) First = paraphimosis; second = phimosis", "The pairing is reversed — inability to retract is phimosis, not paraphimosis."], ["C) Both are phimosis", "They are distinct entities."], ["D) Both are paraphimosis", "They are distinct entities."]]}, {"n": 173, "s": "A 27-year-old man who has smoked 20 cigarettes daily since age 16 presents with a 6-month history of right foot claudication and a non-healing ulcer on the right great toe. Radial pulses are normal, but distal pedal pulses are absent. Angiography shows segmental occlusion of the distal tibial and pedal arteries with corkscrew collaterals, and normal proximal vessels. Which of the following is the most appropriate management?", "o": [["A", "Percutaneous transluminal angioplasty of the tibial vessels"], ["B", "Femoropopliteal bypass grafting"], ["C", "Complete cessation of tobacco smoking"], ["D", "Low-dose aspirin with pentoxifylline alone"]], "c": ["C)", "Complete cessation of tobacco smoking"], "co": "Thromboangiitis obliterans (Buerger disease) — a segmental inflammatory-occlusive disease of small- and medium-sized vessels in young male smokers; distal, with normal proximal pulses; the only effective treatment is complete smoking cessation.", "ct": "Interpretation — treating Buerger disease at its true target: smoking cessation, not revascularization", "w": "The age, heavy smoking history, distal distribution (tibial/pedal with normal proximal pulses), and corkscrew collaterals are classic Buerger disease (thromboangiitis obliterans). Because the disease is segmental, inflammatory, and relentlessly progressive as long as tobacco exposure continues, revascularization — endovascular or open — is ineffective and doomed to fail. Complete cessation of smoking is the only intervention proven to halt progression and prevent amputation.", "d": "Young male smoker + distal (tibial/pedal) segmental occlusion + corkscrew collaterals + normal proximal pulses = Buerger disease, where intervention is futile and cessation is the only therapy that halts progression.", "t": "Treatment misdirection — endovascular revascularization offered when smoking cessation is the only established therapy", "f": "Buerger disease: young male smoker, normal proximal pulses, distal segmental occlusions, corkscrew collaterals → smoking cessation is the treatment, NOT angioplasty or bypass. Never offer revascularization for Buerger disease.", "r": "Buerger disease → complete smoking cessation; revascularization (angioplasty/bypass) is ineffective and contraindicated as primary therapy.", "x": [["A) Percutaneous transluminal angioplasty of the tibial vessels", "Angioplasty is ineffective in Buerger disease: the occlusions are distal, segmental, and inflammatory, and vessels re-thrombose as long as smoking continues — the disease is not amenable to endovascular salvage."], ["B) Femoropopliteal bypass grafting", "Bypass grafting fails in Buerger disease because the run-off vessels are diseased and the inflammatory process continues with ongoing tobacco use; surgery is reserved only for rare critical situations and still requires cessation."], ["D) Low-dose aspirin with pentoxifylline alone", "Aspirin and pentoxifylline provide symptomatic adjunct benefit at best; neither halts the disease — without smoking cessation the ulcer will progress to gangrene."]]}, {"n": 174, "s": "A 34-year-old woman with Graves disease and a large multinodular goitre has compressive symptoms and declining response to antithyroid drugs. She is planned for total thyroidectomy. Which pre-operative step is essential to avoid a thyroid storm?", "o": [["A", "Operate immediately regardless of thyroid state"], ["B", "Achieve euthyroid state with antithyroid drugs + beta-blocker ± Lugol iodine"], ["C", "Start high-dose levothyroxine"], ["D", "Only give steroids"]], "c": ["B)", "Achieve euthyroid state with antithyroid drugs + beta-blocker ± Lugol iodine"], "co": "Graves surgery — must be euthyroid pre-op (ATD + beta-blocker ± iodine) to prevent storm", "ct": "Analysis/synthesis", "w": "Surgery for Graves is indicated for compressive symptoms, suspicion of malignancy, large goitre, or failure of medical therapy. A critical safety step is rendering the patient euthyroid before operation with antithyroid drugs and a beta-blocker (and often Lugol iodine pre-op to reduce vascularity), because operating on an unprepared hyperthyroid gland risks thyroid storm. Starting levothyroxine would worsen thyrotoxicosis.", "d": "Graves thyroidectomy needs euthyroid prep (ATD, beta-blocker, sometimes Lugol) to avoid storm", "t": "Treatment ladder — euthyroid prep (ATD + beta-blocker ± iodine) before Graves thyroidectomy", "f": "Graves thyroidectomy: operate only euthyroid (ATD + beta-blocker ± Lugol) to prevent storm", "r": "Graves surgery indicated for compressive/malignant/failed-medical; must be euthyroid pre-op (avoid storm)", "x": [["A) Operate immediately regardless of thyroid state", "Operating on an unprepared hyperthyroid gland risks fatal thyroid storm."], ["C) Start high-dose levothyroxine", "Levothyroxine would worsen thyrotoxicosis pre-operatively."], ["D) Only give steroids", "Steroids alone do not achieve euthyroidism; ATD + beta-blocker are key."]]}, {"n": 175, "s": "After a total thyroidectomy, a patient develops immediate stridor, respiratory distress, and a fixed midline (paramedian) cord bilaterally. What is the emergency and management?", "o": [["A", "Hypocalcaemic laryngospasm — give calcium"], ["B", "Bilateral recurrent laryngeal nerve injury — airway obstruction; urgent tracheostomy/intubation"], ["C", "Wound haematoma — open at bedside"], ["D", "Unilateral RLN injury — observe"]], "c": ["B)", "Bilateral recurrent laryngeal nerve injury — airway obstruction; urgent tracheostomy/intubation"], "co": "Bilateral RLN injury — airway emergency (bilateral cord fixation) → tracheostomy", "ct": "Analysis/synthesis", "w": "Bilateral recurrent laryngeal nerve injury fixes both vocal cords in a paramedian position, leaving a small glottic gap and causing acute stridor and airway obstruction — a true emergency requiring immediate intubation or tracheostomy. This is far more dangerous than unilateral (hoarseness only) injury. The distinction from hematoma (which also obstructs but by compression) guides the specific intervention.", "d": "Bilateral RLN injury → both cords paramedian → airway obstruction → urgent airway (tracheostomy)", "t": "Severity under-recognition — bilateral RLN = airway emergency (tracheostomy), not just hoarseness", "f": "Bilateral RLN injury = both cords paramedian → stridor/airway obstruction → urgent tracheostomy", "r": "Bilateral RLN injury: both cords paramedian → airway obstruction → urgent tracheostomy/intubation", "x": [["A) Hypocalcaemic laryngospasm — give calcium", "Hypocalcaemia causes tetany/laryngospasm later, not immediate bilateral cord fixation."], ["C) Wound haematoma — open at bedside", "Hematoma causes compression; the described bilateral cord finding points to RLN, not hematoma."], ["D) Unilateral RLN injury — observe", "Unilateral injury causes hoarseness only; this is bilateral and emergent."]]}, {"n": 176, "s": "A 60-year-old heavy smoker presents with painless gross haematuria. Cystoscopy is normal, but retrograde pyelography shows a filling defect in the renal pelvis. What is the most likely diagnosis?", "o": [["A", "Transitional cell carcinoma of the renal pelvis"], ["B", "Renal cell carcinoma"], ["C", "Calculous disease"], ["D", "Renal tuberculosis"]], "c": ["A)", "Transitional cell carcinoma of the renal pelvis"], "co": "Upper-tract transitional cell carcinoma — smoking, haematuria, filling defect", "ct": "Interpretation", "w": "Transitional (urothelial) cell carcinoma arises anywhere along the urothelium — bladder, renal pelvis, ureter. In a smoker with haematuria and a renal pelvic filling defect but normal bladder, upper-tract TCC is likely. It is treated with nephroureterectomy. Smoking is the dominant risk factor.", "d": "Smoker + painless haematuria + renal pelvis filling defect (normal cystoscopy) = upper-tract TCC", "t": "Clinical Mimic — TCC (smoking, urothelium) vs RCC (parenchymal mass)", "f": "Smoker + haematuria + pelvic filling defect = upper-tract TCC (not RCC)", "r": "Upper-tract TCC = smoker + haematuria + pelvic filling defect; nephroureterectomy", "x": [["B) Renal cell carcinoma", "RCC would show a parenchymal mass, not a mucosal filling defect, and often has venous extension."], ["C) Calculous disease", "A stone would show a radiopaque/computed filling defect but with colic, not a smooth mucosal lesion."], ["D) Renal tuberculosis", "Renal TB causes sterile pyuria and irregular calyces, not a discrete filling defect."]]}, {"n": 177, "s": "A 2-month-old boy (born at 34 weeks) is brought in because his mother notices a bulge in the right groin whenever he cries. The bulge reduces easily with gentle pressure. Examination confirms a reducible right indirect inguinal hernia. What is the most appropriate management?", "o": [["A", "Observe and review at school age"], ["B", "Elective herniotomy arranged promptly"], ["C", "Emergency surgery today"], ["D", "Hernia truss until 1 year of age"]], "c": ["B)", "Elective herniotomy arranged promptly"], "co": "Paediatric inguinal hernia — timing of repair", "ct": "Interpretation (infant hernia → prompt elective herniotomy)", "w": "An indirect inguinal hernia in an infant, especially one born preterm, should be repaired by elective herniotomy soon after diagnosis because of the high risk of incarceration in the first year.", "d": "Reducible infant indirect inguinal hernia → prompt elective herniotomy; prolonged delay risks incarceration", "t": "Age-appropriate differential — infant hernias are repaired promptly, unlike adult watchful waiting", "f": "Reducible infant hernia = schedule herniotomy; irreducible scrotal mass in a neonate = emergency", "r": "Infant inguinal hernia (reducible) → prompt elective herniotomy; no trusses, no prolonged waiting", "x": [["A) Observe and review at school age", "A: Waiting until school age exposes the infant to a significant risk of incarceration and gonadal damage."], ["C) Emergency surgery today", "C: Emergency surgery is for an irreducible or strangulated hernia, not a reducible one."], ["D) Hernia truss until 1 year of age", "D: Hernia trusses are not used in modern infant hernia care and carry skin and strangulation risks."]]}, {"n": 178, "s": "A 58-year-old has a 5 cm adrenal mass found incidentally. Biochemical workup excludes Cushing, pheochromocytoma, and aldosteronism. What is the recommendation?", "o": [["A", "Surgical resection (size >4 cm raises malignancy concern)"], ["B", "No further action, benign"], ["C", "Observe with no follow-up"], ["D", "Chemotherapy"]], "c": ["A)", "Surgical resection (size >4 cm raises malignancy concern)"], "co": "Adrenal incidentaloma — resect if >4 cm or functioning; else observe", "ct": "Interpretation", "w": "An adrenal incidentaloma with normal biochemistry still warrants assessment of malignant potential by size: masses >4 cm carry a higher risk of adrenocortical carcinoma and are typically resected. Functioning tumours (any size) and those with suspicious imaging features also warrant surgery. Small (<4 cm), non-functioning, benign-appearing lesions are observed with interval imaging. Chemotherapy is not indicated for a localized mass.", "d": "Incidental adrenal mass >4 cm (or any functioning) → resection for malignancy risk", "t": "Treatment ladder — adrenalectomy if >4 cm or functioning; observe if small/benign", "f": "Adrenal incidentaloma >4 cm (or functioning) → resect; small benign → observe", "r": "Adrenal incidentaloma: resect if >4 cm or functioning (malignancy risk); else observe", "x": [["B) No further action, benign", "A 5 cm mass is not simply 'benign' without resection given size-based malignancy risk."], ["C) Observe with no follow-up", "Follow-up imaging is needed; complete neglect risks missing malignancy."], ["D) Chemotherapy", "Chemotherapy is not first-line for a localized adrenal mass."]]}, {"n": 179, "s": "An 80-year-old man with long-standing bladder outlet obstruction has constant dribbling incontinence with a palpable bladder. Which type of incontinence is this?", "o": [["A", "Overflow incontinence"], ["B", "Stress incontinence"], ["C", "Urge incontinence"], ["D", "Functional incontinence"]], "c": ["A)", "Overflow incontinence"], "co": "Overflow incontinence — chronic retention → dribbling, palpable bladder", "ct": "Interpretation", "w": "Overflow incontinence occurs when the bladder is chronically overdistended (outlet obstruction, neurogenic bladder, medications) and dribbles once above capacity; the bladder is palpable/percussable. Stress incontinence is leakage with exertion (sphincter weakness); urge is sudden desire (detrusor overactivity); functional is inability to reach the toilet. Distinguishing type guides therapy.", "d": "Incomplete emptying + dribbling + palpable bladder = overflow incontinence", "t": "Classification trap — overflow (palpable full bladder) vs stress/urge", "f": "Dribbling + palpable bladder = overflow incontinence (chronic retention)", "r": "Overflow incontinence = chronic retention → dribbling + palpable bladder (BPH, neurogenic)", "x": [["B) Stress incontinence", "Stress incontinence is leakage on coughing/exertion with an empty bladder."], ["C) Urge incontinence", "Urge incontinence is a sudden compelling desire with detrusor overactivity."], ["D) Functional incontinence", "Functional incontinence is environmental/cognitive inability to reach a toilet."]]}, {"n": 180, "s": "A 42-year-old man develops severe acute perianal pain after lifting a heavy object 2 days ago. Examination shows a tender, firm, bluish subcutaneous lump at the anal verge. What is the most appropriate management?", "o": [["A", "Rubber band ligation"], ["B", "Excision of the thrombosed external haemorrhoid"], ["C", "Topical glyceryl trinitrate ointment"], ["D", "Urgent haemorrhoidectomy of all three columns"]], "c": ["B)", "Excision of the thrombosed external haemorrhoid"], "co": "Haemorrhoids — thrombosed external haemorrhoid", "ct": "Analysis/synthesis (acute thrombosed external haemorrhoid → excision)", "w": "An acutely thrombosed external haemorrhoid within the first 72 hours is best treated by excision of the thrombosed haemorrhoid under local anaesthesia, giving rapid pain relief and a lower recurrence rate than conservative care.", "d": "Acute (<72 h) thrombosed EXTERNAL haemorrhoid → excision of the thrombus under local anaesthetic gives immediate relief", "t": "Treatment misdirection — banding treats INTERNAL haemorrhoids; excision treats thrombosed external ones", "f": "Banding = internal (prolapse); excision = thrombosed external (acute pain)", "r": "Thrombosed external haemorrhoid (<72 h) → excision; after 72 h → conservative analgesia", "x": [["A) Rubber band ligation", "A: Rubber band ligation is for symptomatic internal haemorrhoids, not a thrombosed external lump."], ["C) Topical glyceryl trinitrate ointment", "C: GTN ointment relaxes the internal sphincter for fissures and internal haemorrhoids; it does not remove an acute thrombus."], ["D) Urgent haemorrhoidectomy of all three columns", "D: Routine three-column haemorrhoidectomy is for severe internal haemorrhoids — excessive here."]]}, {"n": 181, "s": "A 62-year-old man presents with fresh rectal bleeding and tenesmus for 2 months. Digital rectal examination reveals a firm, ulcerated mass on the anterior rectal wall, and biopsy confirms adenocarcinoma. Which investigation is most useful for local staging to plan treatment?", "o": [["A", "CT abdomen and pelvis with contrast"], ["B", "MRI of the pelvis"], ["C", "Transabdominal ultrasound"], ["D", "Barium enema"]], "c": ["B)", "MRI of the pelvis"], "co": "Rectal carcinoma — local staging investigations", "ct": "Interpretation (investigation selection for rectal cancer staging)", "w": "MRI of the pelvis is the investigation of choice for local staging of rectal cancer, assessing tumour depth and the circumferential resection margin (mesorectal fascia) to plan neoadjuvant therapy and surgery.", "d": "Rectal adenocarcinoma → MRI pelvis for T stage and mesorectal fascia involvement; CT is for distant spread", "t": "Investigation hierarchy — MRI for local rectal staging; CT for metastatic disease", "f": "Rectal cancer: local staging = MRI pelvis; distant staging = CT chest/abdomen/pelvis", "r": "Rectal cancer → MRI pelvis (CRM/TME planning) + CT for metastases", "x": [["A) CT abdomen and pelvis with contrast", "A: CT is best for detecting distant metastases but has poor soft-tissue resolution for mesorectal fascia involvement."], ["C) Transabdominal ultrasound", "C: Transabdominal ultrasound cannot visualise the lower rectum adequately for staging."], ["D) Barium enema", "D: Barium enema is historical — it shows luminal contour, not extramural tumour spread."]]}, {"n": 182, "s": "A nursing-home resident on an inhaled steroid for COPD develops difficulty eating with a red oropharynx and white, curd-like, removable plaques. Most likely diagnosis?", "o": [["A", "Oropharyngeal candidiasis"], ["B", "Herpes simplex pharyngitis"], ["C", "Hairy leukoplakia"], ["D", "Leukoedema"]], "c": ["A)", "Oropharyngeal candidiasis"], "co": "Oropharyngeal candidiasis - steroid inhaler + white curd-like plaques", "ct": "Interpretation", "w": "Oral candidiasis (thrush) is favoured by inhaled or systemic steroids, and presents with erythema and white curd-like plaques that can be scraped off leaving a raw base. It is treated with a topical or systemic antifungal. This is a recalled exam pattern (Q84).", "d": "White curd-like removable plaques + steroid inhaler usage = oral candidiasis; antifungal", "t": "Confusing removable curd-like plaques with adherent lesions (leukoplakia/hairy leukoplakia)", "f": "Steroid inhaler + white curd-like removable plaques = oral candidiasis; antifungal", "r": "Oral candidiasis: white curd-like removable plaques (steroid use, immunocompromise) -> antifungal. Distinguish from adherent leukoplakia.", "x": [["B) Herpes simplex pharyngitis", "herpes pharyngitis has vesicles/ulcers, not curd-like plaques"], ["C) Hairy leukoplakia", "hairy leukoplakia is a non-removable, corrugated white lesion of the tongue edge in immunocompromise"], ["D) Leukoedema", "leukoedema is a benign gray-white haze of the buccal mucosa, not curd-like plaques"]]}, {"n": 183, "s": "A 60-year-old heavy smoker with hoarseness for over 3 weeks and progressive voice change is referred. What is the most appropriate next step?", "o": [["A", "Reassure that it is a viral laryngitis and review in 6 months"], ["B", "Refer for direct (flexible) laryngoscopy +/- biopsy to exclude laryngeal carcinoma"], ["C", "Start oral steroids"], ["D", "Prescribe voice rest only"]], "c": ["B)", "Refer for direct (flexible) laryngoscopy +/- biopsy to exclude laryngeal carcinoma"], "co": "Laryngeal carcinoma - hoarseness >3 weeks in a smoker warrants specialist evaluation", "ct": "Interpretation", "w": "Hoarseness persisting beyond 3 weeks in a high-risk patient (smoker, older adult) is a red flag for laryngeal carcinoma and warrants direct/flexible laryngoscopy with biopsy. Persistent hoarseness is the principal early symptom of glottic cancer. Do not reassure or treat symptomatically without visualization.", "d": "Persistent hoarseness >3 weeks (esp. smoker) = laryngeal carcinoma until proven otherwise; direct laryngoscopy +/- biopsy", "t": "Reassuring persistent hoarseness in a smoker as simple laryngitis", "f": "Hoarseness >3 weeks in an adult smoker = laryngeal carcinoma until excluded; laryngoscopy + biopsy", "r": "Persistent hoarseness >3 weeks, especially in a smoker, needs direct laryngoscopy to exclude laryngeal carcinoma.", "x": [["A) Reassure that it is a viral laryngitis and review in 6 months", "persistent hoarseness in a smoker is not simply viral laryngitis"], ["C) Start oral steroids", "steroids do not diagnose or treat laryngeal cancer"], ["D) Prescribe voice rest only", "voice rest alone is inadequate without excluding malignancy"]]}, {"n": 184, "s": "A 60-year-old on aspirin has a brisk anterior nosebleed from Little's area that is ongoing. Gentle pressure, decongestant and cautery have controlled the bleeding. However he is at risk of rebleeding. Which measure is most important for initial management?", "o": [["A", "Immediate posterior nasal packing in all cases"], ["B", "Maintain pressure: sit upright, lean forward, pinch the cartilaginous nose for 10-20 minutes, and treat the bleeding point (silver nitrate/coagulation), plus avoid nasal trauma"], ["C", "Routine hospital admission for every patient"], ["D", "Start broad-spectrum IV antibiotics prophylactically"]], "c": ["B)", "Maintain pressure: sit upright, lean forward, pinch the cartilaginous nose for 10-20 minutes, and treat the bleeding point (silver nitrate/coagulation), plus avoid nasal trauma"], "co": "Epistaxis management - anterior packing/pressure + cautery, first aid", "ct": "Interpretation", "w": "Most anterior epistaxis arises from Little's area (Kiesselbach plexus). Initial management is first aid (sit upright, lean forward, pinch the nose for 10-20 minutes), then direct cautery or chemical (silver nitrate) coagulation of the visible vessel, and addressing bleeding risk factors. Posterior packing/admission/antibiotics are reserved for uncontrolled or posterior bleeding.", "d": "Anterior Little's area bleed: sit forward, pinch nose 10-20 min, then cauterize/coagulate visible point; avoid re-trauma", "t": "Jumping to posterior packing/admission for a controllable anterior bleed", "f": "Anterior Little's area bleed: compress nose, cauterize point; posterior packing only if uncontrolled", "r": "Anterior epistaxis: sit forward, pinch cartilaginous nose 10-20 min, cauterize visible point (silver nitrate); posterior packing/admission if uncontrolled.", "x": [["A) Immediate posterior nasal packing in all cases", "posterior packing is only for uncontrolled posterior bleeds, not routine first aid"], ["C) Routine hospital admission for every patient", "most anterior bleeds are managed as outpatient, not routine admission"], ["D) Start broad-spectrum IV antibiotics prophylactically", "prophylactic IV antibiotics are not indicated for a controlled anterior bleed"]]}, {"n": 185, "s": "A child has right ear pain and tenderness when the ear is pulled, with no fever. Examination shows an inflamed, edematous ear canal with scanty yellow discharge and normal tympanic membrane. Diagnosis and first-line treatment?", "o": [["A", "Acute otitis media; oral amoxicillin"], ["B", "Acute otitis externa; topical antibiotic/antiseptic ear drops and keep the ear dry"], ["C", "Mastoiditis; IV antibiotics"], ["D", "Furunculosis of the pinna; incision and drainage"]], "c": ["B)", "Acute otitis externa; topical antibiotic/antiseptic ear drops and keep the ear dry"], "co": "Acute otitis externa - tender pinna/canal, normal TM; topical drops + dry ear", "ct": "Interpretation", "w": "Acute otitis externa ('swimmer's ear') is inflammation of the external auditory canal. Pain on tragus/pinna traction, a narrowed edematous canal and a normal TM distinguish it from otitis media. Treatment is topical antibiotic/antiseptic drops and keeping the ear dry; systemic antibiotics are rarely needed unless spreading cellulitis. A recalled exam pattern.", "d": "Ear pain with pinna/canal tenderness, edematous canal, normal TM, no fever = otitis externa; treat topical drops + dry care", "t": "Calling it otitis media - the key discriminator is pinna/canal tenderness with a normal TM", "f": "Ear pain + canal tenderness/edema, normal TM, no fever = otitis externa; topical drops + dry ear", "r": "AOE: otalgia worsened by pinna traction, edematous canal, normal TM; treat topical antibiotic/antiseptic drops + dry care.", "x": [["A) Acute otitis media; oral amoxicillin", "otitis media has a bulging TM and usually fever, not canal tenderness with normal TM"], ["C) Mastoiditis; IV antibiotics", "mastoiditis has postauricular swelling/erythema and protrusion of the pinna"], ["D) Furunculosis of the pinna; incision and drainage", "acute furunculosis is a localized abscess; the picture here is diffuse canal inflammation"]]}, {"n": 186, "s": "A 10-year-old has fever, sore throat and exudative tonsils with painful cervical lymphadenopathy and no cough. Rapid antigen test is positive for Group A streptococcus. Which is the most important reason to treat with antibiotics?", "o": [["A", "To shorten the illness and prevent acute rheumatic fever and suppurative complications"], ["B", "To prevent viral spread to contacts"], ["C", "To avoid tonsillectomy in adulthood"], ["D", "It is not needed because it is a virus"]], "c": ["A)", "To shorten the illness and prevent acute rheumatic fever and suppurative complications"], "co": "GAS tonsillitis - antibiotics to prevent rheumatic fever", "ct": "Interpretation", "w": "Antibiotics for group A streptococcal tonsillitis (in addition to symptomatic relief) primarily prevent acute rheumatic fever and suppurative complications such as quinsy. Treatment is indicated when GAS is confirmed. These symptoms without cough and with tender cervical nodes favour bacterial over viral aetiology.", "d": "GAS + exudative tonsillitis/adenopathy = treat antibiotics to prevent acute rheumatic fever and local suppuration", "t": "Thinking antibiotics are only for symptom duration, not rheumatic-fever prevention", "f": "Confirmed GAS tonsillitis: antibiotics prevent acute rheumatic fever and suppurative complications", "r": "Treat GAS tonsillitis (positive rapid test, exudates, tender nodes, no cough) with antibiotics to prevent acute rheumatic fever and quinsy.", "x": [["B) To prevent viral spread to contacts", "antibiotics do not treat or prevent viral spread"], ["C) To avoid tonsillectomy in adulthood", "antibiotics are not given to prevent adult tonsillectomy"], ["D) It is not needed because it is a virus", "the positive GAS test indicates bacteria, not a virus"]]}, {"n": 187, "s": "A 45-year-old has recurrent episodes of vertigo lasting 30-40 minutes, fluctuating sensorineural hearing loss, tinnitus and a sense of aural fullness in one ear. Between episodes he is well. Dix-Hallpike and neurological examination are normal. Diagnosis?", "o": [["A", "Benign paroxysmal positional vertigo"], ["B", "Meniere's disease"], ["C", "Vestibular schwannoma"], ["D", "Labyrinthitis"]], "c": ["B)", "Meniere's disease"], "co": "Meniere's disease - episodic vertigo + fluctuating SNHL + tinnitus + aural fullness", "ct": "Interpretation", "w": "Meniere's disease is characterised by recurrent spontaneous vertigo attacks lasting 20 minutes to hours, with fluctuating low-frequency sensorineural hearing loss, tinnitus and aural fullness. Dix-Hallpike is negative (distinguishes from BPPV). This is a recalled exam pattern.", "d": "Episodic vertigo (minutes to hours) + fluctuating SNHL/tinnitus/aural fullness = Meniere's; normal Dix-Hallpike excludes BPPV", "t": "Choosing BPPV because Dix-Hallpike is mentioned - but negative Dix-Hallpike plus fullness/fluctuating HL favours Meniere", "f": "Episodic vertigo + fluctuating SNHL + fullness, negative Dix-Hallpike = Meniere's disease", "r": "Meniere's: recurrent vertigo (20min-hours) + fluctuating SNHL + tinnitus + fullness; negative Dix-Hallpike; salt restriction/diuretics, betahistine.", "x": [["A) Benign paroxysmal positional vertigo", "BPPV gives brief (seconds) positional vertigo with a positive Dix-Hallpike"], ["C) Vestibular schwannoma", "vestibular schwannoma gives progressive unilateral SNHL with poor speech discrimination, not episodic attacks with fullness"], ["D) Labyrinthitis", "labyrinthitis is a single acute prolonged vertigo with hearing loss, not recurring attacks"]]}, {"n": 188, "s": "A 30-year-old woman has recurrent, unexpected episodes of intense fear peaking within minutes, with palpitations, sweating, tremor, chest discomfort, choking and a feeling of imminent death. She now avoids crowded places for fear of an episode. What is the most likely diagnosis?", "o": [["A", "Panic disorder"], ["B", "Generalised anxiety disorder"], ["C", "Social anxiety disorder"], ["D", "Obsessive-compulsive disorder"]], "c": ["A)", "Panic disorder"], "co": "Panic disorder — recurrent unexpected panic attacks peaking in minutes, with avoidance", "ct": "Interpretation", "w": "Panic disorder is characterised by recurrent, unexpected panic attacks (a surge of intense fear peaking within minutes with palpitations, dyspnoea, tremor, depersonalisation, fear of dying). Fear of future attacks can drive agoraphobic avoidance.", "d": "Paroxysmal fear + autonomic surge peaking in minutes + avoidance = panic disorder", "t": "Calling paroxysmal panic 'generalised anxiety' or 'social anxiety'", "f": "Sudden surges peaking in minutes (not chronic worry) + fear of the next attack = panic disorder", "r": "Recurrent unexpected panic attacks (fear peaking in minutes with autonomic surge) plus anticipatory fear/avoidance = panic disorder; SSRIs are first-line treatment.", "x": [["B) Generalised anxiety disorder", "GAD is chronic, generalised worry present most days, not paroxysmal surges peaking in minutes"], ["C) Social anxiety disorder", "social anxiety is fear of negative evaluation in social/performance situations, not spontaneous panic surges"], ["D) Obsessive-compulsive disorder", "OCD is obsessions/compulsions, not paroxysmal autonomic fear attacks"]]}, {"n": 189, "s": "A 35-year-old man with long-standing opioid dependence stops use. He has rhinorrhoea, lacrimation, yawning, piloerection, mydriasis, muscle cramps, diarrhoea and anxiety. What is the most likely diagnosis and appropriate pharmacotherapy?", "o": [["A", "Opioid intoxication — give naloxone"], ["B", "Serotonin syndrome — give cyproheptadine"], ["C", "Alcohol withdrawal — give benzodiazepines"], ["D", "Opioid withdrawal — treat with methadone or buprenorphine (and lofexidine adjunctively)"]], "c": ["D)", "Opioid withdrawal — treat with methadone or buprenorphine (and lofexidine adjunctively)"], "co": "Opioid withdrawal — sympathomimetic-opposite features; treat with methadone/buprenorphine", "ct": "Interpretation", "w": "Opioid withdrawal produces the opposite of intoxication: mydriasis (not pinpoint pupils), rhinorrhoea, lacrimation, yawning, piloerection, diarrhoea, cramps and anxiety. Treatment uses opioid replacement (methadone or buprenorphine) with supportive agents like lofexidine (alpha-2 agonist) for adrenergic symptoms.", "d": "Rhinorrhoea + mydriasis (opposite of pinpoint) + lacrimation + GI cramps after stopping opioids = withdrawal", "t": "Giving naloxone (which precipitates/worsens withdrawal) or confusing withdrawal with intoxication", "f": "Mydriasis + lacrimation/rhinorrhoea/GI after stopping opioids = withdrawal (naloxone is for INTOXICATION); treat with methadone/buprenorphine", "r": "Opioid withdrawal (mydriasis, rhinorrhoea, lacrimation, GI cramps) is treated with methadone/buprenorphine; naloxone is for opioid intoxication and would worsen withdrawal.", "x": [["A) Opioid intoxication — give naloxone", "naloxone is for opioid INTOXICATION (pinpoint pupils, respiratory depression); giving it in withdrawal precipitates/worsens symptoms"], ["B) Serotonin syndrome — give cyproheptadine", "serotonin syndrome has clonus, hyperreflexia and follows serotonergic drugs, not this opioid-withdrawal picture"], ["C) Alcohol withdrawal — give benzodiazepines", "this is opioid, not alcohol, withdrawal; the treatment of choice is opioid replacement, not benzodiazepines"]]}, {"n": 190, "s": "A 69-year-old hypertensive, diabetic smoker has stepwise cognitive decline with abrupt worsening, emotional lability, focal neurologic signs and gait difficulty. MRI shows multiple lacunar infarcts and white-matter disease. What is the most likely diagnosis?", "o": [["A", "Alzheimer disease"], ["B", "Frontotemporal dementia"], ["C", "Normal-pressure hydrocephalus"], ["D", "Vascular dementia"]], "c": ["D)", "Vascular dementia"], "co": "Vascular dementia — stepwise decline + focal signs + vascular risk factors + infarcts on imaging", "ct": "Interpretation", "w": "Vascular dementia features stepwise/abrupt cognitive decline with focal neurologic signs, a history of stroke/vascular risk factors, and subcortical infarcts/white-matter disease on imaging. It differs from Alzheimer's gradual amnestic progression.", "d": "Stepwise decline + focal signs + vascular risk factors + lacunar infarcts = vascular dementia", "t": "Attributing stepwise, focal, vascular-pattern dementia to Alzheimer disease", "f": "Stepwise + focal signs + vascular risk factors + lacunes = vascular dementia (vs gradual amnestic AD)", "r": "Stepwise cognitive decline with focal deficits, vascular risk factors and lacunar/white-matter changes = vascular dementia.", "x": [["A) Alzheimer disease", "Alzheimer disease is gradual and amnestic without focal neurologic signs or a stepwise stroke-like course"], ["B) Frontotemporal dementia", "frontotemporal dementia presents with early behaviour/personality or language change, not stepwise focal vascular decline"], ["C) Normal-pressure hydrocephalus", "normal-pressure hydrocephalus has gait apraxia, urinary incontinence and ventriculomegaly (Hakim triad), not prominent lacunar infarcts"]]}, {"n": 191, "s": "A 60-year-old man with known COPD has ABG: pH 7.36, PaCO2 66 mmHg, HCO3 36 mmol/L. Which interpretation is correct?", "o": [["A", "Acute respiratory acidosis with no compensation"], ["B", "Metabolic alkalosis with respiratory compensation"], ["C", "Mixed acidosis and alkalosis"], ["D", "Chronic respiratory acidosis with renal compensation"]], "c": ["D)", "Chronic respiratory acidosis with renal compensation"], "co": "Compensation never overshoots", "ct": "Interpretation", "w": "Chronic respiratory acidosis shows a high HCO3 from renal compensation with pH closer to normal; compensation moves pH toward normal but never overshoots.", "d": "High PaCO2 with a near-normal pH and elevated HCO3 is the source's chronic-compensation pattern.", "t": "High HCO3 alone is read as metabolic alkalosis — the trap is forgetting HCO3 also rises as renal compensation.", "f": "A high HCO3 with high PaCO2 and near-normal pH = compensation for chronic respiratory acidosis, not primary metabolic alkalosis.", "r": "Chronic respiratory acidosis shows a high HCO3 from renal compensation with pH closer to normal; compensation moves pH toward normal but never overshoots.", "x": [["A) Acute respiratory acidosis with no compensation", "A near-normal pH with a markedly raised CO2 shows the kidneys have had time to retain bicarbonate — this is chronic, not acute."], ["B) Metabolic alkalosis with respiratory compensation", "The primary driver is the high PaCO2; the HCO3 is the compensation, not the primary disorder."], ["C) Mixed acidosis and alkalosis", "Compensation has moved the pH toward normal without overshooting — a single process, not a mixed disorder."]]}, {"n": 192, "s": "A 68-year-old man with known lung cancer develops progressive back pain, bilateral leg weakness, and urinary retention over 48 hours. What is the most appropriate immediate management?", "o": [["A", "High-dose dexamethasone and urgent MRI of the spine"], ["B", "Outpatient follow-up with analgesia"], ["C", "Urgent MRI after starting physiotherapy"], ["D", "Spinal X-ray series only"]], "c": ["A)", "High-dose dexamethasone and urgent MRI of the spine"], "co": "Metastatic spinal cord compression", "ct": "Interpretation", "w": "Back pain with weakness and bladder symptoms in known cancer is metastatic spinal cord compression: dexamethasone immediately, then urgent MRI and oncology/neurosurgery/radiotherapy pathway — never wait for complete paralysis.", "d": "Leg weakness + urinary retention + known lung cancer is the source's exact cord-compression cluster.", "t": "'Routine musculoskeletal back pain' is the planted misread; bladder/weakness signs make it an emergency.", "f": "Cancer + back pain + weakness/bladder signs = cord compression: dexamethasone + urgent MRI now.", "r": "Back pain with weakness and bladder symptoms in known cancer is metastatic spinal cord compression: dexamethasone immediately, then urgent MRI and oncology/neurosurgery/radiotherapy pathway — never wait for complete paralysis.", "x": [["B) Outpatient follow-up with analgesia", "Back pain plus weakness/bladder symptoms in known cancer is cord compression until proven otherwise — the source names outpatient analgesia a fatal miss."], ["C) Urgent MRI after starting physiotherapy", "Steroids and imaging are the emergency pathway; physiotherapy is not the first step."], ["D) Spinal X-ray series only", "Plain X-rays do not assess cord compression; urgent MRI is required."]]}, {"n": 193, "s": "A 40-year-old woman with Crohn disease (extensive ileal resection) develops recurrent calcium oxalate stones. What is the underlying mechanism?", "o": [["A", "Enteric hyperoxaluria from fat malabsorption"], ["B", "Hyperparathyroidism"], ["C", "Primary urate overproduction"], ["D", "Renal tubular acidosis"]], "c": ["A)", "Enteric hyperoxaluria from fat malabsorption"], "co": "Enteric hyperoxaluria — fat malabsorption → increased oxalate absorption", "ct": "Analysis/synthesis", "w": "In fat malabsorption (Crohn, ileal resection, bariatric surgery), unabsorbed fatty acids bind calcium, leaving oxalate free to be absorbed in the colon → hyperoxaluria and calcium oxalate stones. This is 'enteric hyperoxaluria'. Management addresses the diarrhoea and restricts oxalate; calcium supplements (taken with meals) can bind oxalate.", "d": "IBD/bariatric/ileal resection + fat malabsorption → enteric hyperoxaluria → calcium oxalate stones", "t": "Clinical Mimic — IBD/bariatric → oxalate stones (enteric hyperoxaluria)", "f": "Fat malabsorption (Crohn/resection) → enteric hyperoxaluria → calcium oxalate stones", "r": "Enteric hyperoxaluria: fat malabsorption → free oxalate absorbed → Ca oxalate stones (Crohn, bariatric)", "x": [["B) Hyperparathyroidism", "Primary HPT causes hypercalciuria but not specifically in the setting of ileal resection."], ["C) Primary urate overproduction", "Urate overproduction causes uric acid, not calcium oxalate, stones."], ["D) Renal tubular acidosis", "RTA causes calcium phosphate stones, not this post-resection picture."]]}, {"n": 194, "s": "A 50-year-old man with gout presents with renal colic. Plain abdominal X-ray shows no visible stone, but CT confirms a renal calculus. What is the most likely composition and treatment principle?", "o": [["A", "Uric acid — radiolucent, treat with urine alkalinization"], ["B", "Calcium oxalate — radio-opaque, treat with thiazide"], ["C", "Struvite — infected urine, treat with antibiotics alone"], ["D", "Cystine — hereditary, treat with hydration only"]], "c": ["A)", "Uric acid — radiolucent, treat with urine alkalinization"], "co": "Uric acid stone — radiolucent, gout association, alkalinize urine", "ct": "Interpretation", "w": "Uric acid stones are radiolucent (invisible on plain X-ray) and occur in hyperuricaemia (gout, myeloproliferative disorders, chemotherapy). Unlike calcium stones, they are dissolved by alkalinizing the urine (potassium citrate, target pH 6.5-7.0) and by lowering urate (allopurinol/febuxostat). Thiazides would worsen uric acid stones.", "d": "Gout + radiolucent stone = uric acid → alkalinize urine (and xanthine oxidase inhibitors)", "t": "Clinical Mimic — radiolucent (uric acid) vs radio-opaque (calcium oxalate)", "f": "Gout + radiolucent stone = uric acid → alkalinize urine (not thiazide)", "r": "Uric acid stone = radiolucent + gout → urine alkalinization (K-citrate) + xanthine oxidase inhibitor", "x": [["B) Calcium oxalate — radio-opaque, treat with thiazide", "Calcium oxalate is radio-opaque; thiazide is for hypercalciuric stones, not uric acid."], ["C) Struvite — infected urine, treat with antibiotics alone", "Struvite requires stone removal plus antibiotics, not antibiotics alone."], ["D) Cystine — hereditary, treat with hydration only", "Cystine needs more than hydration (penicillamine/captopril + alkalinization)."]]}, {"n": 195, "s": "A patient requires reoperation for recurrent thyroid nodules after a previous partial thyroidectomy. Which complication risk is substantially higher than at first surgery?", "o": [["A", "Recurrent laryngeal nerve and parathyroid injury (distorted planes)"], ["B", "Carotid artery injury"], ["C", "Tracheal perforation"], ["D", "Chyle leak"]], "c": ["A)", "Recurrent laryngeal nerve and parathyroid injury (distorted planes)"], "co": "Reoperative thyroid surgery — higher RLN and parathyroid injury risk", "ct": "Interpretation", "w": "Reoperative thyroid/parathyroid surgery is higher-risk because fibrosis and distorted anatomy obscure the recurrent laryngeal nerves and parathyroid glands, raising rates of permanent RLN injury and hypoparathyroidism. Intraoperative nerve monitoring and meticulous dissection (or autotransplantation of parathyroid) are used. The other structures listed are not the dominant incremental risk.", "d": "Reoperative neck surgery → scarred distorted planes → higher RLN/parathyroid injury", "t": "Severity under-recognition — reoperative thyroid = higher RLN/parathyroid injury (plan accordingly)", "f": "Reoperative thyroid surgery = distorted planes → higher RLN + parathyroid injury risk", "r": "Reoperative thyroid/parathyroid: scarred planes → higher RLN + parathyroid injury; use monitoring", "x": [["B) Carotid artery injury", "Carotid injury is not the characteristic incremental risk of reoperative thyroid surgery."], ["C) Tracheal perforation", "Tracheal perforation is rare and not the main concern."], ["D) Chyle leak", "Chyle leak is a thoracic duct issue, not typical in thyroid reoperation."]]}, {"n": 196, "s": "In which of the following patients is treatment of asymptomatic bacteriuria clearly indicated?", "o": [["A", "A healthy postmenopausal woman"], ["B", "A pregnant woman at 20 weeks"], ["C", "An elderly man in a nursing home"], ["D", "A young woman with a single positive screen"]], "c": ["B)", "A pregnant woman at 20 weeks"], "co": "Asymptomatic bacteriuria — treat in pregnancy and before urologic procedures", "ct": "Interpretation", "w": "Asymptomatic bacteriuria should be screened for and treated in pregnancy (to prevent pyelonephritis) and before invasive urologic procedures (to prevent endocarditis/sepsis). In healthy non-pregnant adults, elderly, or catheterised patients, treatment is NOT recommended (it does not improve outcomes and promotes resistance).", "d": "Treat asymptomatic bacteriuria only in pregnancy and before invasive urologic procedures", "t": "Treatment misdirection — treating ASB in elderly/healthy (harmful) vs pregnancy (indicated)", "f": "Treat ASB only in pregnancy & pre-urologic procedure; not in elderly/healthy", "r": "Asymptomatic bacteriuria: treat in PREGNANCY and before urologic procedures; not in elderly/healthy", "x": [["A) A healthy postmenopausal woman", "Healthy postmenopausal women do not benefit from treating ASB."], ["C) An elderly man in a nursing home", "Elderly/nursing-home residents should not be treated for ASB routinely."], ["D) A young woman with a single positive screen", "A young non-pregnant woman with ASB does not require treatment."]]}, {"n": 197, "s": "A 71-year-old woman with chronic constipation presents with sudden colicky abdominal pain, vomiting and absolute constipation. Abdominal X-ray shows a single grossly dilated large bowel loop in the left upper quadrant with two air-fluid levels and dilation of adjacent small bowel. What is the most likely diagnosis?", "o": [["A", "Sigmoid volvulus"], ["B", "Caecal volvulus"], ["C", "Gastric volvulus"], ["D", "Acute colonic pseudo-obstruction"]], "c": ["B)", "Caecal volvulus"], "co": "Caecal volvulus — X-ray pattern", "ct": "Interpretation (volvulus localisation)", "w": "Caecal volvulus produces a large, gas-filled caecum that migrates to the left upper quadrant, with accompanying small-bowel obstruction — in contrast to the pelvic sigmoid loop.", "d": "Dilated loop in the left upper quadrant + small-bowel dilation → caecal volvulus; the sigmoid 'coffee bean' arises from the pelvis", "t": "Clinical Mimic — both volvuli show a dilated loop; the location and small-bowel dilation distinguish caecal volvulus", "f": "LUQ dilated loop + SBO = caecal volvulus; pelvic 'coffee bean' = sigmoid", "r": "Caecal volvulus = dilated caecum in the LUQ + small-bowel obstruction → right hemicolectomy", "x": [["A) Sigmoid volvulus", "A: Sigmoid volvulus gives a 'coffee bean' arising from the pelvis/left lower quadrant, usually without prominent small-bowel dilation."], ["C) Gastric volvulus", "C: Gastric volvulus causes vomiting with a gas-filled stomach that fails to drain by nasogastric tube, not a colonic loop."], ["D) Acute colonic pseudo-obstruction", "D: Pseudo-obstruction dilates the whole colon diffusely without a single twisted loop."]]}, {"n": 198, "s": "A 45-year-old man undergoing general anaesthesia for laparoscopic cholecystectomy has a laryngeal mask airway (LMA) for airway management. Twenty minutes into the procedure he regurgitates, oxygen saturation falls to 82%, and ventilation through the LMA becomes increasingly difficult with audible gurgling. What is the most appropriate next step?", "o": [["A", "Increase the fresh gas flow and deepen anaesthesia"], ["B", "Remove the LMA, suction the oropharynx, and intubate the trachea"], ["C", "Continue positive-pressure ventilation through the LMA"], ["D", "Apply cricoid pressure and leave the LMA in situ"]], "c": ["B)", "Remove the LMA, suction the oropharynx, and intubate the trachea"], "co": "Aspiration under a supraglottic airway — an LMA does not protect the trachea; on regurgitation with desaturation, the airway must be converted to a definitive cuffed endotracheal tube after suctioning.", "ct": "Analysis/synthesis — abandoning a failed supraglottic airway for a definitive one when aspiration threatens", "w": "A laryngeal mask is a supraglottic device that does not seal the larynx or protect the airway from regurgitated gastric contents. Once regurgitation and desaturation occur, the priority is to remove the LMA, suction the pharynx, and secure the trachea with a cuffed endotracheal tube — both to protect against further aspiration and to ventilate reliably. Persisting with the LMA under these conditions permits ongoing aspiration and worsening gas exchange.", "d": "Regurgitation + desaturation + gurgling through an LMA = the supraglottic airway is no longer safe; persisting with it invites massive aspiration — the LMA must come out and the trachea must be intubated.", "t": "Treatment misdirection — persisting with a supraglottic airway instead of converting to a definitive one", "f": "An LMA never protects the airway — regurgitation with desaturation = remove LMA, suction, intubate. LMA rescue (i-gel, LMA) is for cannot-intubate-cannot-ventilate, not for an aspirating patient.", "r": "Regurgitation/aspiration risk under an LMA → remove device, suction, and secure a definitive cuffed endotracheal tube.", "x": [["A) Increase the fresh gas flow and deepen anaesthesia", "Increasing fresh gas flow and deepening anaesthesia does nothing for regurgitation or a failing supraglottic seal — aspiration continues."], ["C) Continue positive-pressure ventilation through the LMA", "Continuing positive-pressure ventilation through a leaking, gurgling LMA forces further gastric contents into the trachea — the opposite of safe management."], ["D) Apply cricoid pressure and leave the LMA in situ", "Cricoid pressure cannot reliably prevent aspiration with a supraglottic device in place and does not restore a failing airway — the LMA must be removed."]]}, {"n": 199, "s": "A 34-year-old man who had a perianal abscess drained 3 months ago now reports intermittent seropurulent discharge from the drainage site. Examination shows an external opening 2 cm from the anal verge, ANTERIOR to the transverse anal line. According to Goodsall's rule, what is the most likely course of the fistula tract?", "o": [["A", "It runs radially and straight to an internal opening in the same quadrant"], ["B", "It curves posteriorly to open in the posterior midline"], ["C", "It tracks upwards to a supralevator space without an internal opening"], ["D", "It connects to the contralateral anal crypt"]], "c": ["A)", "It runs radially and straight to an internal opening in the same quadrant"], "co": "Goodsall's rule — fistula tract course", "ct": "Recall (Goodsall's rule application)", "w": "By Goodsall's rule, an external opening anterior to the transverse anal line communicates by a short straight radial tract with the corresponding anal crypt.", "d": "External opening ANTERIOR to the transverse anal line → short straight radial tract; posterior openings → curve to the posterior midline", "t": "Pattern recognition — anterior = straight radial; posterior = curved to midline", "f": "Anterior opening = straight tract; posterior opening = curved (horseshoe) to the posterior midline", "r": "Anterior external opening → straight radial tract; posterior opening → curves to the posterior midline", "x": [["B) It curves posteriorly to open in the posterior midline", "B: Curving to the posterior midline is the rule for openings POSTERIOR to the transverse anal line."], ["C) It tracks upwards to a supralevator space without an internal opening", "C: A supralevator extension is a secondary tract, not the default course of an anterior fistula."], ["D) It connects to the contralateral anal crypt", "D: Fistulas open at the pectinate line in the same radial quadrant, not the contralateral side."]]}, {"n": 200, "s": "A 40-year-old has recurrent painful swelling of the right cheek that worsens at mealtimes. The swelling resolves between meals and a painful mass is felt in Wharton's duct. Which gland and management?", "o": [["A", "Parotid; total parotidectomy"], ["B", "Submandibular gland; sialolithiasis - manage with sialogogues, massage, or ductal removal/ectomy if recurrent"], ["C", "Sublingual; antibiotics only"], ["D", "Parotid; radiotherapy"]], "c": ["B)", "Submandibular gland; sialolithiasis - manage with sialogogues, massage, or ductal removal/ectomy if recurrent"], "co": "Sialolithiasis - submandibular stone, worse at meals; sialogogues/removal", "ct": "Interpretation", "w": "Salivary calculi (sialolithiasis) most commonly affect the submandibular gland (Wharton's duct) because of its long, upward-draining duct and more alkaline, viscous saliva. Classically the gland swells painfully during meals. Management is conservative with sialogogues/hydration/massage, or removal of the stone (or sialadenectomy) when recurrent or obstructive.", "d": "Painful glandular swelling worse at mealtimes + ductal mass = sialolithiasis; most common in submandibular gland", "t": "Assuming parotid or giving antibiotics for a ductal stone", "f": "Mealtime-related gland swelling + ductal mass = sialolithiasis, submandibular; sialogogues, stone removal if needed", "r": "Sialolithiasis: submandibular stone causing pain/swelling with meals; sialogogues/hydration/massage; surgical removal if recurrent.", "x": [["A) Parotid; total parotidectomy", "this is submandibular sialolithiasis; parotidectomy is inappropriate"], ["C) Sublingual; antibiotics only", "sublingual is less common and antibiotics do not remove a stone"], ["D) Parotid; radiotherapy", "radiotherapy is not used for a benign ductal stone"]]}], "c": 200}}

Test Series 2026