Adrenal insufficiency is an endocrine, or hormonal, disorder that occurs when your adrenal glands don't produce enough of certain hormones. Your adrenal glands are located just above your kidneys. They produce important hormones including cortisol, aldosterone, adrenaline and androgens.
Adrenal insufficiency can be primary (about 1 in 4 cases) or secondary (about 3 in 4 cases):
- Primary adrenal insufficiency is also known as Addison's disease, named after the doctor who described this condition. Addison’s disease is rare. It affects 110–144 of every 1 million people in developed countries. It occurs when your adrenal glands are damaged (from infection, injury or autoimmune problems) and can't produce enough of the adrenal hormones cortisol and sometimes aldosterone.
- Secondary adrenal insufficiency is more common and occurs when your pituitary gland (a pea-sized gland at the base of your brain) doesn't produce enough adrenocorticotropin (ACTH). This hormone stimulates your adrenal glands to produce the hormone cortisol. Without enough ACTH your adrenal glands can shrink over time.