A 44-year-old woman is found to have a 2.1 cm right adrenal adenoma on CT done for an unrelated reason. She has no symptoms of adrenal hormone excess. Biochemical workup shows: suppressed plasma renin, aldosterone-to-renin ratio 35 (normal <20), and 24-h urine aldosterone elevated. Cortisol suppresses adequately on overnight 1-mg DST. The most appropriate next step in management is:

• A Adrenal vein sampling ✓
• B Observation and repeat imaging in 12 months
• C Right adrenalectomy
• D Spironolactone therapy

Explanation

In primary aldosteronism confirmed biochemically, adrenal vein sampling (AVS) is required to lateralize the source before committing to unilateral adrenalectomy. CT/MRI cannot reliably distinguish unilateral adenoma from bilateral hyperplasia because CT may miss small contralateral adenomas. AVS differentiates lateralized from bilateral disease; if lateralized, surgery is curative; if bilateral, spironolactone is first-line. Spironolactone without lateralization misses a surgical cure, and immediate surgery without AVS risks operating on the wrong side.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.