Heart Failure USMLE Step 1 Practice Question
A 62-year-old man with a history of hypertension and anterior wall myocardial infarction 2 years ago presents to the emergency department with a 3-week history of progressive dyspnea, orthopnea, and bilateral lower extremity edema. His wife reports he has been gaining weight despite decreased appetite. On examination, temperature is 37.2°C, heart rate is 102/min, blood pressure is 148/92 mmHg, respiratory rate is 22/min, and oxygen saturation is 92% on room air. Jugular venous pressure is elevated at 10 cm H₂O, lungs have bibasilar crackles, and a prominent S3 gallop is appreciated. Echocardiography demonstrates a left ventricular ejection fraction of 32% with global hypokinesis and dilated left ventricle. Serum albumin is 3.8 g/dL (normal), and urinalysis shows no proteinuria. Which of the following mechanisms best accounts for the development of his peripheral edema?
Answer choices
- ADecreased plasma oncotic pressure from malnutrition and hepatic dysfunction
- BIncreased capillary hydrostatic pressure secondary to systemic venous congestion and impaired renal perfusionCorrect answer
- CLymphatic obstruction from cardiac enlargement compressing mediastinal and peripheral lymphatic vessels
- DIncreased capillary permeability from acute inflammatory cytokine release triggered by myocardial necrosis
- ERenal tubular sodium reabsorption defect causing secondary hyperaldosteronism
- FDecreased interstitial oncotic pressure from reduced hepatic albumin synthesis
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