Question: I had Cushing’s due to an adrenal tumor and from what I’m told, no longer require replacement medication. My 8 AM ACTH is elevated and very variable and my 8 AM cortisol levels vary as well. Should this be a concern? Does the variability have anything to do with how tired I am? Should I consider restarting replacement?

Answer: Following adrenalectomy for an adrenal adenoma causing Cushing’s syndrome, it may take weeks to months for the hypothalamic-pituitary-adrenal system to return to normal function. We define normal steroid levels as the presence of sufficient steroid production to allow people to participate in a healthy manner during normal life activities, and sufficient steroid production to counter stress, such as fever or surgery. Cortisol production is variable in that fasting levels may differ, even in people with “normal” adrenal function. We look for serum cortisol levels > 18, or normal cortisol levels following an endocrine test such as a cortrosyn (ACTH) stimulation test or insulin tolerance test. If someone has been taken off steroid replacement, and is still fatigued, then we continue to assess steroid production. If the cortisol values are consistently in the normal range, then we usually hold on steroid replacement. However, if the levels are consistently below the target, such as defined above, then we often recommend that steroid replacement be restarted, with repeat testing down the line to see if the steroids can be stopped again. In my experience, the ACTH values in someone recovering from an adrenalectomy are variable, and of unclear use.

By Dr. Laurence Katznelson MD (Fall, 2008)