Other causes may be permanent, such as pituitary tumors, pituitary surgery, or radiation damage to the pituitary. Some causes of secondary AI may be temporary, such as taking certain prescription medicines like prednisone, hydrocortisone, or dexamethasone. But in secondary AI, the pituitary gland does not send enough ACTH to the adrenal glands. Normally, the pituitary gland makes a hormone called ACTH, which tells the adrenal glands to make cortisol. Secondary AI: Problems with the pituitary gland cause secondary AI.

Other causes of primary AI include bleeding in the glands, infections, genetic (inherited) diseases, and surgical removal of the adrenal glands. When adrenal glands are damaged, they can't produce hormones. Primary AI: The most common cause of primary AI is autoimmune disease, meaning the body's defense system attacks and destroys the body's own tissues. In AI, the adrenal cortex does not make enough steroid hormones. The outer layer (cortex) of the adrenal glands makes three types of steroid hormones. The adrenal glands, located on top of the kidneys, make hormones that are essential for body functions. Only an endocrinologist, an expert in hormones, should diagnose AI using standard tests. The adrenal glands do not get “adrenal fatigue” or lose function because of mental or physical stress.

Production of aldosterone is normal in secondary AI. It results when the pituitary gland, a small gland near the brain, does not signal the adrenal glands to make cortisol. Secondary AI is the far more common type of AI. Usually, production of aldosterone and androgens (the two other types of steroid hormones made by the adrenal glands) is also low. Primary adrenal insufficiency (AI), also called Addison's disease, is a rare condition where the adrenal glands do not work properly and cannot make enough cortisol (a “stress” hormone).

Signs of adrenal problems