Clinical and biochemical evaluation of Cushing's syndrome

The diagnosis and differential diagnosis of Cushing's syndrome remain a clinical challenge. This article summarizes the clinical features of Cushing's syndrome and critically reviews the various endocrine tests utilized for screening, diagnosis, and localization. Special consideration is given to several novel tests based on the administration of corticotropin-releasing hormone. The role of imaging and inferior petrosal sinus catheterization is discussed within the context of a general algorithm proposed for evaluating patients with suspected Cushing's syndrome.