MD Internal Medicine 5 — Questions and Answers
Question 1: A 52-year-old man presents with a new right bundle branch block and first-degree AV block. He recently returned from camping in Connecticut and has a migratory circular rash. What is the most appropriate treatment?
- Azithromycin orally
- Doxycycline orally for 14–21 days (Correct answer)
- IV ceftriaxone for 14 days
- Ciprofloxacin orally
Correct answer: Doxycycline orally for 14–21 days
Early disseminated Lyme disease with cardiac involvement (AV block <second-degree) is treated with oral doxycycline; IV ceftriaxone is reserved for high-degree AV block or other severe manifestations.
Question 2: A 70-year-old woman with heart failure and an EF of 30% is found to have a serum potassium of 3.0 mEq/L while on furosemide. What is the best approach to prevent ventricular arrhythmias in this setting?
- Increase furosemide dose
- Add spironolactone and replete potassium (Correct answer)
- Switch to hydrochlorothiazide
- Start magnesium supplementation only
Correct answer: Add spironolactone and replete potassium
Spironolactone (an aldosterone antagonist) reduces mortality in HFrEF, potassium-spares, and corrects loop-diuretic–induced hypokalemia, which is a major arrhythmia risk in the setting of a dilated failing heart.
Question 3: A 45-year-old woman presents with progressively worsening dysphagia to solids and liquids, regurgitation of undigested food, and weight loss. Barium swallow shows a 'bird's beak' narrowing at the gastroesophageal junction. What is the diagnosis?
- Esophageal adenocarcinoma
- Achalasia (Correct answer)
- Diffuse esophageal spasm
- Zenker's diverticulum
Correct answer: Achalasia
Achalasia is characterized by failure of LES relaxation and loss of peristalsis, causing dysphagia to both solids and liquids, regurgitation, and the classic 'bird's beak' on barium swallow.
Question 4: A patient with severe COPD exacerbation is placed on supplemental oxygen. After 30 minutes, he becomes drowsy and his PaCO2 rises from 55 to 75 mmHg. What is the most likely mechanism?
- Oxygen-induced cardiac depression
- Loss of hypoxic pulmonary vasoconstriction causing increased V/Q mismatch (Haldane effect) (Correct answer)
- Pneumonia worsening secretions
- Worsening bronchospasm from oxygen
Correct answer: Loss of hypoxic pulmonary vasoconstriction causing increased V/Q mismatch (Haldane effect)
High-flow O2 in chronic CO2 retainers causes the Haldane effect (CO2 displaced from hemoglobin) and worsens V/Q mismatch by reversing hypoxic pulmonary vasoconstriction, raising PaCO2.
Question 5: A 28-year-old man presents with episodic severe headache, diaphoresis, and palpitations. Blood pressure during an episode is 240/130 mmHg. Which initial pharmacologic treatment is contraindicated?
- Phentolamine IV
- Phenoxybenzamine
- Propranolol alone without alpha-blockade (Correct answer)
- Prazosin
Correct answer: Propranolol alone without alpha-blockade
In pheochromocytoma, using a beta-blocker before adequate alpha-blockade leaves alpha receptors unopposed, causing severe vasoconstriction and a potentially fatal hypertensive crisis.
Question 6: A 60-year-old man with hypertension on amlodipine presents with symmetric ankle edema. Examination reveals no JVD, normal heart sounds, and no proteinuria. What is the most likely cause?
- New-onset heart failure
- Nephrotic syndrome
- Dihydropyridine calcium channel blocker-induced edema (Correct answer)
- Deep vein thrombosis
Correct answer: Dihydropyridine calcium channel blocker-induced edema
Dihydropyridine CCBs (e.g., amlodipine, nifedipine) cause dose-dependent peripheral edema from preferential arterial dilation without compensatory venodilation, increasing hydrostatic pressure in capillaries.
Question 7: A 55-year-old man with poorly controlled gout has a serum uric acid of 10.2 mg/dL. He has had three attacks in the past year and has a visible tophus on his right ear. Which medication is the preferred urate-lowering therapy?
- Colchicine long-term
- Allopurinol titrated to uric acid goal <6 mg/dL (Correct answer)
- Indomethacin as needed
- Probenecid as first-line
Correct answer: Allopurinol titrated to uric acid goal <6 mg/dL
Allopurinol, a xanthine oxidase inhibitor, is first-line urate-lowering therapy for gout; the target serum uric acid is <6 mg/dL (or <5 mg/dL with tophi) to dissolve urate deposits.
MD Internal Medicine 5
A 52-year-old man presents with a new right bundle branch block and first-degree AV block.
He recently returned from camping in Connecticut and has a migratory circular rash.
What is the most appropriate treatment?