Calcium and Parathyroid USMLE Step 1 Practice Question
A 42-year-old man presents with resistant hypertension (BP 168/102 mmHg, HR 88/min) and fatigue. Laboratory studies reveal hypokalemia (K+ 3.1 mEq/L), metabolic alkalosis (HCO3- 32 mEq/L), and suppressed plasma renin activity (0.3 ng/mL/hr). Serum calcium is elevated at 10.8 mg/dL with low PTH (15 pg/mL). Urinary potassium is inappropriately elevated. Recent imaging shows no renal artery stenosis. He denies licorice use and takes no glucocorticoids. Which diagnosis best explains his clinical presentation?
Answer choices
- APrimary adrenal insufficiency
- BPheochromocytoma
- CPrimary hyperaldosteronismCorrect answer
- DSIADH
- ESecondary hyperaldosteronism due to renal artery stenosis
- FApparent mineralocorticoid excess from 11-beta-HSD deficiency
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