A patient has hypotension, hyponatraemia, hyperkalaemia and skin pigmentation. What is the best confirmatory test?
Answer and explanation
Correct answer: A. A short Synacthen (ACTH stimulation) test
- Step 1: The pattern fits primary adrenal insufficiency (Addison's disease), where ACTH drives pigmentation. Step 2. A short Synacthen test shows an inadequate cortisol rise in adrenal failure. Answer: A short Synacthen (ACTH stimulation) test. Why not the others: Dexamethasone suppression screens for Cushing syndrome. Water deprivation investigates diabetes insipidus. An oral glucose tolerance test is used for acromegaly or diabetes.
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