Endocrinology · NEET PG Preparation Medicine
A 52-year-old man presents with progressive fatigue, skin hyperpigmentation, orthostatic hypotension, and weight loss. Laboratory workup reveals hypo…
Practice question from Endocrinology (NEET PG Preparation Medicine), with the correct answer and a step-by-step solution.
medium · MCQ · Q-455B17
A 52-year-old man presents with progressive fatigue, skin hyperpigmentation, orthostatic hypotension, and weight loss. Laboratory workup reveals hyponatremia, hyperkalemia, and a low morning serum cortisol level. An ACTH stimulation test shows a baseline cortisol of 3 mcg/dL and a 60-minute post-cosyntropin cortisol of 5 mcg/dL. Which of the following additional findings is most characteristic of primary adrenal insufficiency compared to secondary adrenal insufficiency?
- A.Severe hypoglycemia
- B.Hyperpigmentation and hyperkalemiaCorrect answer
- C.Metabolic alkalosis
- D.Elevated thyroid-stimulating hormone
Solution
Primary adrenal insufficiency (Addison disease) involves destruction of the adrenal cortex, leading to mineralocorticoid deficiency (causing hyperkalemia and metabolic acidosis) and loss of negative feedback causing elevated ACTH and its cleavage byproduct MSH, resulting in skin hyperpigmentation. Secondary adrenal insufficiency spares the zona glomerulosa (aldosterone is regulated by the renin-angiotensin system), so potassium remains normal, and ACTH levels are low, preventing hyperpigmentation.
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