MD Internal Medicine 5

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?

Accepted Answer

Doxycycline orally for 14–21 days

Answer

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?

Accepted Answer

Add spironolactone and replete potassium

Answer

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?

Accepted Answer

Achalasia

Answer

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?

Accepted Answer

Loss of hypoxic pulmonary vasoconstriction causing increased V/Q mismatch (Haldane effect)

Answer

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?

Accepted Answer

Propranolol alone without alpha-blockade

Answer

In pheochromocytoma, using a beta-blocker before adequate alpha-blockade leaves alpha receptors unopposed, causing severe vasoconstriction and a potentially fatal hypertensive crisis.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD Internal Medicine 5