A 38-year-old man presents with hypertension refractory to three agents, hypokalaemia (K 2.8 mEq/L), and metabolic alkalosis. Plasma aldosterone:renin ratio is 45 ng/dL per ng/mL/hr. CT abdomen shows bilateral adrenal hyperplasia. What is the definitive localisation test before treatment decision?
- A Adrenal vein sampling (AVS) for lateralisation ✓
- B Repeat CT with adrenal protocol
- C 131-I-norcholesterol scintigraphy
- D Dexamethasone suppression test
Correct answer: A. Adrenal vein sampling (AVS) for lateralisation
Explanation
In primary hyperaldosteronism with bilateral adrenal hyperplasia on CT, adrenal vein sampling (AVS) is mandatory before deciding on surgery versus medical therapy. CT can miss small adenomas or misidentify nodules; AVS confirms unilateral excess aldosterone secretion (lateralisation ratio >4:1 corrected for cortisol). Unilateral disease warrants adrenalectomy; bilateral disease is treated with mineralocorticoid receptor antagonists. The Endocrine Society 2016 guidelines mandate AVS in all surgical candidates.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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