Addison's disease, also known as primary adrenal insufficiency, is a rare condition that affects the body's hormonal activity. It is estimated that Addison's disease affects 1 to 4 out of every 100,000 individuals. This disease is named after Dr. Thomas Addison, who discovered it in 1849.
Addison's disease occurs when the body's adrenal glands are not able to make enough of the hormones cortisol or aldosterone. Each hormone works differently and plays important roles in the human body.
Cortisol helps the body respond to stress. It also helps maintain blood pressure and blood sugar; slow the immune system's inflammatory response; and regulate the metabolism of proteins, carbohydrates, and fats. Aldosterone is involved in keeping adequate blood pressure and water and salt balance in the body.
Addison's disease is usually caused by an autoimmune reaction, where the body attacks its own adrenal glands and prevents them from functioning properly. Other possible causes of Addison's disease include tuberculosis, trauma with bleeding into the adrenal glands, surgery, fungal infections, and cancer.
A similar condition called secondary adrenal insufficiency occurs when the pituitary gland does not make enough adrenocorticotropin (ACTH), a hormone that stimulates the adrenal glands to produce cortisol and aldosterone. Possible causes of secondary adrenal insufficiency include pituitary tumors, brain surgery, reduced blood flow to the brain, or brain infections. It can also be caused by suddenly stopping corticosteroid medications after taking them for a prolonged period of time. In this case, the problem is usually temporary.