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Primary adrenal insufficiency — USMLE Step 3 MCQ

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HardInternal Medicine (chronic management)Primary adrenal insufficiencyUSMLE Step 3

A 41-year-old woman has fatigue, weight loss, salt craving, nausea, and dizziness. Blood pressure is 88/54 mm Hg with hyperpigmentation of palmar creases. Sodium is 128 mEq/L, potassium is 5.8 mEq/L, and morning cortisol is low with elevated ACTH. Which of the following is the most likely explanation for this patient's findings?

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Correct answer: E — Autoimmune destruction of the adrenal cortex

Primary adrenal insufficiency commonly results from autoimmune adrenalitis, causing low cortisol, low aldosterone, and elevated ACTH.

Reference: Endocrine Society Primary Adrenal Insufficiency Guideline