Adrenal Disorders — Viva

The scenario

Mrs R is a 40-year-old marketing manager referred by her GP for evaluation of suspected Cushing syndrome. Over 8 months she has developed central weight gain (8 kg), a rounding of her face, easy bruising on her forearms, wide purple striae on her abdomen, and progressive difficulty climbing stairs (proximal leg weakness). She has new hypertension (BP 165/98) and new type 2 diabetes (HbA1c 64 mmol/mol). She has amenorrhoea for 4 months and low mood. She is not on any glucocorticoid therapy. ^[1]

Investigations from the GP: 1 mg overnight dexamethasone suppression test — cortisol 290 nmol/L (failed suppression). Two 24-hour urine free cortisol collections — 580 and 640 nmol/24h (reference below 220). Late-night salivary cortisol — elevated. Plasma ACTH — 92 pg/mL (reference 7.2-63.3). Pituitary MRI — a 4 mm right-sided microadenoma. Serum potassium — 4.0 mmol/L (normal). ^[1]