ABIM MCQ 4 — Questions and Answers
Question 1: A 68-year-old man with a history of MI presents with exertional chest pain. Nuclear stress test shows a large reversible perfusion defect in the LAD territory. EF is 45%. Coronary angiography reveals 80% stenosis of the proximal LAD. What is the preferred revascularization strategy?
- Coronary artery bypass grafting (CABG) (Correct answer)
- Percutaneous coronary intervention (PCI)
- Medical management alone
- Cardiac rehabilitation without revascularization
Correct answer: Coronary artery bypass grafting (CABG)
CABG is preferred over PCI for proximal LAD disease, especially with reduced EF, due to superior long-term survival and reduced repeat revascularization rates.
Question 2: A 44-year-old woman presents with polyuria, polydipsia, and a serum sodium of 148 mEq/L. Water deprivation test fails to concentrate urine (Uosm 180 mOsm/kg). After desmopressin administration, urine osmolality rises to 680 mOsm/kg. What is the diagnosis?
- Central diabetes insipidus (Correct answer)
- Nephrogenic diabetes insipidus
- Primary polydipsia
- SIADH
Correct answer: Central diabetes insipidus
A robust response to desmopressin (urine Osm >50% increase) confirms central DI, where ADH is deficient but renal tubules respond normally.
Question 3: A 29-year-old man presents with fever, arthritis of the knee, and a painless penile ulcer. Urethral culture is negative for gonorrhea. He also has conjunctivitis and hyperkeratotic lesions on his palms. What is the most likely diagnosis?
- Reactive arthritis (formerly Reiter's syndrome) (Correct answer)
- Disseminated gonococcal infection
- Secondary syphilis
- Behcet's disease
Correct answer: Reactive arthritis (formerly Reiter's syndrome)
Reactive arthritis classically follows a GI or urogenital infection and presents with arthritis, urethritis, conjunctivitis, and skin/mucous membrane lesions (keratoderma blennorrhagicum).
Question 4: A 77-year-old woman with hypertension and atrial fibrillation is started on amiodarone for rhythm control. Six months later, she presents with dyspnea and is found to have bilateral interstitial infiltrates on CXR. PFTs show a restrictive pattern with reduced DLCO. What is the most likely cause?
- Amiodarone pulmonary toxicity (Correct answer)
- Congestive heart failure exacerbation
- Pneumonia
- Pulmonary embolism
Correct answer: Amiodarone pulmonary toxicity
Amiodarone pulmonary toxicity typically presents months to years after initiation and causes interstitial pneumonitis, manifesting as dyspnea with restrictive physiology and reduced DLCO.
Question 5: A 53-year-old man presents with confusion and asterixis. His wife notes he has been drinking heavily for 20 years. Labs reveal ammonia 142 µmol/L, total bilirubin 4.2 mg/dL, and INR 2.1. What precipitating factor should be investigated first in hepatic encephalopathy?
- Gastrointestinal bleeding (Correct answer)
- High-protein meal
- Spontaneous bacterial peritonitis
- Constipation
Correct answer: Gastrointestinal bleeding
GI bleeding is the most common precipitant of hepatic encephalopathy in cirrhotics, as blood in the gut is a large nitrogenous load that dramatically raises ammonia.
Question 6: A 41-year-old woman presents with fatigue, weight gain, dry skin, and constipation. TSH is 12.4 mIU/L and free T4 is 0.6 ng/dL. Anti-TPO antibodies are markedly elevated. What is the treatment of choice?
- Levothyroxine monotherapy (Correct answer)
- Levothyroxine plus liothyronine (T3)
- Desiccated thyroid extract
- Observation with repeat TSH in 6 months
Correct answer: Levothyroxine monotherapy
Levothyroxine is the standard treatment for Hashimoto's hypothyroidism due to its consistent potency, long half-life, and established safety profile.
Question 7: A 60-year-old man with stage IV non-small cell lung cancer (NSCLC) is found to have an EGFR exon 19 deletion on molecular profiling. He has an ECOG performance status of 1. What is the preferred first-line therapy?
- Osimertinib (third-generation EGFR TKI) (Correct answer)
- Erlotinib (first-generation EGFR TKI)
- Carboplatin plus pemetrexed chemotherapy
- Pembrolizumab immunotherapy
Correct answer: Osimertinib (third-generation EGFR TKI)
Osimertinib demonstrated superior PFS and OS versus first/second-generation EGFR TKIs in the FLAURA trial and is now the standard first-line agent for EGFR-mutant NSCLC.
ABIM MCQ 4
A 68-year-old man with a history of MI presents with exertional chest pain.
Nuclear stress test shows a large reversible perfusion defect in the LAD territory.
EF is 45%.
Coronary angiography reveals 80% stenosis of the proximal LAD.
What is the preferred revascularization strategy?