Investigating for the aetiology of Cushing’s syndrome: where we can go wrong

Abstract

The diagnosis of Cushing's syndrome as well as delineating its aetiology can be often challenging, especially in the mild cases with atypical features. Although the combined clinical features such as the age, gender and the severity of the hypercortisolism can usually help to differentiate between pituitary ACTH hyper secretion from an ectopic ACTH source, this may sometimes be inaccurate. The presence of caveats in most biochemical testing and imaging modalities as well as the relative unavailability of certain dynamic tests and catheter based studies can contribute to the dilemma.