Adrenal Disorders USMLE Step 1 Practice Question
A 41-year-old man with a 10-year history of hypertension presents to clinic for routine follow-up. On examination, blood pressure is 158/96 mmHg. Laboratory studies show serum potassium 3.1 mEq/L, serum sodium 144 mEq/L, and serum creatinine 0.9 mg/dL. Plasma renin activity is suppressed at 0.1 ng/mL/hr (normal: 0.6-1.6). Plasma aldosterone is 28 ng/dL (normal: 3-16). A non-contrast CT of the abdomen reveals a 1.3-cm left adrenal nodule with homogeneous enhancement and no lipid content. After intravenous saline loading (500 mL/hr for 4 hours), aldosterone concentration decreases only to 24 ng/dL. Which of the following is the most likely diagnosis?
Answer choices
- AIdiopathic hyperaldosteronism
- BGlucocorticoid-remediable aldosteronism
- CSecondary hyperaldosteronism from renal artery stenosis
- DPrimary hyperaldosteronism due to bilateral adrenal hyperplasia
- EAldosterone-producing adenomaCorrect answer
- FAdrenocortical carcinoma with aldosterone excess
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