Question: I had successful pituitary surgery for Cushing’s 15 years ago. Recently my lab work showed elevated cortisol. What cortisol or ACTH levels are considered high enough for further testing? What would be the next level of testing for re-occurring Cushing’s? 

Answer: The recurrence of Cushing’s disease is relatively frequent and has been described even decades after initial remission. While the diagnosis of Cushing’s is sometimes difficult , the diagnosis of recurrence could be even  harder to make.  The best test for diagnosing early recurrence seems to be salivary cortisol (in a good assay), followed by dexamethasone test suppression and at last, urine free cortisol, but most of the time more than one test is needed.

It is not possible to comment on specific cut-off levels, since every patient needs to be considered individually. In the presence of clinical symptoms and high cortisol/ACTH, further testing for hypercortisolism is clearly necessary.

By Dr. Maria Fleseriu, Spring, 2015