ELECTROLYTE QUIZ

The answer is B.

This patient has hyperaldosteronism with hypertension and hypokalemic metabolic alkalosis. Renal artery stenosis should cause elevated renin and aldosterone levels. Cushing and Liddle syndrome are both associated with suppressed renin and aldosterone levels. Both primary hyperaldosteronism and glucocorticoid-remediable aldosteronism could exhibit the same laboratory values, with elevated plasma aldosterone and suppressed renin levels, but primary hyperaldosteronism is much more common.

The Question

An asymptomatic 28-year-old male is found to be hypertensive on routine physical exam.

Laboratory Studies

Serum sodium 142 mEq/L

Serum potassium 3.4 mEq/L

Serum chloride 108 mEq/L

Serum bicarbonate 30 mEq/L

Blood urea nitrogen 15 mg/dL

Serum creatinine 0.8 mg/dL

Plasma renin activity 1.2 ng/mL/hr (Normal range 1-6)

Plasma aldosterone 33 ng/dL (Normal range 5-20)

Which of the following is the most likely cause of this patient’s alkalosis:

A. Cushing syndrome

B. Primary hyperaldosteronism

C. Liddle syndrome

D. Glucocorticoid-remediable aldosteronism

E. Renal artery stenosis