Adrenal insufficiency is an endocrine, or hormonal, disorder that occurs when the adrenal glands do not produce enough of certain hormones. The adrenal glands are located just above the kidneys.
Adrenal insufficiency can be primary or secondary. Addison’s disease, the common term for primary adrenal insufficiency, occurs when the adrenal glands are damaged and cannot produce enough of the adrenal hormone cortisol. The adrenal hormone aldosterone may also be lacking. Addison’s disease affects 110 to 144 of every 1 million people in developed countries.1
Secondary adrenal insufficiency occurs when the pituitary gland—a pea-sized gland at the base of the brain—fails to produce enough adrenocorticotropin (ACTH), a hormone that stimulates the adrenal glands to produce the hormone cortisol. If ACTH output is too low, cortisol production drops. Eventually, the adrenal glands can shrink due to lack of ACTH stimulation. Secondary adrenal insufficiency is much more common than Addison’s disease.