Heart Failure USMLE Step 1 Practice Question
A 62-year-old man with a 10-year history of hypertension presents to the clinic complaining of progressive dyspnea on exertion for 3 months, waking at night short of breath, and swelling in both ankles that worsens throughout the day. On examination, his jugular venous pressure is elevated at 8 cm H₂O, his point of maximal impulse is displaced laterally to the 6th intercostal space, and a low-pitched S3 gallop is appreciated. Vital signs are notable for a blood pressure of 152/94 mmHg and heart rate of 92 bpm. Chest X-ray demonstrates pulmonary edema with bilateral infiltrates and cardiomegaly. Transthoracic echocardiography shows a left ventricular ejection fraction of 32% with global wall hypokinesis. Serum creatinine is 1.4 mg/dL (baseline 0.9 mg/dL). Which of the following mechanisms best explains the pathophysiology of sodium and water retention in this patient?
Answer choices
- ASuppression of antidiuretic hormone by elevated B-type natriuretic peptide
- BRenal hypoperfusion with subsequent activation of the renin-angiotensin-aldosterone system and sympathetic nervous systemCorrect answer
- CPrimary hyperaldosteronism secondary to adrenal adenoma
- DDirect toxic effects of circulating TNF-α and IL-6 on the proximal tubule
- EExcessive secretion of atrial natriuretic peptide causing increased tubular sodium reabsorption
- FPreferential dilation of the afferent arteriole relative to the efferent arteriole
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