Primary hyperaldosteronism is confirmed biochemically. CT scan shows a normal-appearing bilateral adrenal glands. What is the most appropriate next investigation to guide definitive management?
- A 18F-FDG PET scan
- B Dexamethasone suppression test
- C Adrenal vein sampling (AVS) ✓
- D Metomidate PET
Correct answer: C. Adrenal vein sampling (AVS)
Explanation
Adrenal vein sampling (AVS) is the gold standard for lateralizing aldosterone excess in primary hyperaldosteronism when CT is inconclusive or shows bilateral normal adrenals. It distinguishes unilateral aldosterone-producing adenoma (surgically curable) from bilateral adrenal hyperplasia (managed medically with mineralocorticoid antagonists). CT misses small adenomas (<1 cm) in up to 50% of cases. Metomidate PET is an emerging technique but not yet the standard. Dexamethasone suppression is for cortisol, not aldosterone.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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