Question: My endocrinologist strongly suspects that I have Cushing’s but since some of my tests come back normal, he thinks that I cycle. Is there any consensus on how best to test for cyclic Cushing’s?

Answer: The diagnosis of mild Cushing’s syndrome is difficult and it is especially challenging when the hypercortisolism is intermittent or cyclical. The majority of patients with this type of Cushing’s syndrome have an ACTH secreting tumor (pituitary or non-pituitary). My preference is to secure late night salivary cortisol measurements frequently in patients in whom I think this is a consideration. The majority of patients with Cushing’s syndrome due to an ACTH secreting tumor will have elevations of late night salivary cortisol when their Cushing’s is active. Some experts will try to secure frequent measurements of urine cortisol—either spot urine samples taken late at night or 24 hour collections. I think the saliva test is much easier.

By Dr. James Findling MD (Summer, 2012)