Cushing Syndrome Screening — RACP Adult Medicine MCQ

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EasyEndocrinologyCushing Syndrome ScreeningRACP Adult Medicine

A 45-year-old woman with hypertension, central obesity, moon face, dorsal fat pad, purple striae, and proximal myopathy. She has new-onset diabetes and osteoporosis. Which screening test is most appropriate?

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Correct answer: A — 1 mg overnight dexamethasone suppression test

Clinical features of Cushing syndrome (central obesity, moon face, striae, myopathy, diabetes, osteoporosis) warrant screening. The 1 mg overnight DST is the recommended initial screening test (take dexamethasone 1 mg at 11 pm, measure cortisol at 8 am — suppression <50 nmol/L excludes Cushing). Alternative screens: 24-hour urine free cortisol, late-night salivary cortisol. Two positive screening tests confirm hypercortisolism.

Reference: Endocrine Society – 2015 – Cushing Syndrome; ESA 2024