Question

A 36-year-old woman with suspected Cushing's syndrome has confirmed elevated cortisol. According to UK guidelines, which investigation best differentiates pituitary (Cushing's disease) from ectopic ACTH production?

Accepted Answer

High-dose dexamethasone suppression test

Answer

24-hour urinary free cortisol

Answer

Low-dose dexamethasone suppression test

Answer

CRH stimulation test

Answer

Pituitary MRI

Practice question

A 36-year-old woman with suspected Cushing's syndrome has confirmed elevated cortisol. According to UK guidelines, which investigation best differentiates pituitary (Cushing's disease) from ectopic ACTH production?