Cushing's syndrome: difficulties in diagnosis

Establishment of the precise cause in a patient with Cushing's syndrome remains a major clinical challenge. The following case of a female patient with cyclical Cushing's syndrome illustrates how recent advances such as the introduction of the corticotropin-releasing hormone (CRH) test (in determining the cause of ACTH production) and high-resolution computed tomographic scanning may help in the diagnosis of Cushing's syndrome. As this case study illustrates, precise diagnosis requires thorough initial investigation and possible successive testing.