Cyclical Cushing's: how best to catch the ups and downs

A 68-year-old man with a background of hypertension and type 2 diabetes presented with fluctuating symptoms of muscle aches and pains and tiredness. His initial work-up for the possibility of hypercortisolaemia showed a completely variable pattern, with 24-hour cortisol excretion and serum cortisol post 1 mg dexamethasone suppression test ranging from normal to significantly elevated. A series of salivary cortisol with symptom diary confirmed the cyclical nature of hypercortisolaemia, and his concomitant adrenocorticotropic hormone (ACTH) levels were elevated. An inferior petrosal sinus sampling, performed during hypercortisolaemic phase of his cycle,suggested a central source of ACTH secretion. He had unsuccessful exploration of his pituitary and was eventually treated with bilateral adrenalectomy followed by lifelong steroid replacement. His symptoms improved immediately, and he came off his oral hypoglycaemic and antihypertensive agents within 6 months following his surgery.