What Is Addison's Disease?
One way the body keeps itself in balance is by using chemical messengers called hormones to regulate various functions. Just above each of your kidneys is a small adrenal gland. These glands make hormones essential to a healthy life. When they don't make enough of these hormones, Addison's disease is the result.
Addison's disease is a rare condition. Only one in 100,000 people has it. It can happen at any age to either men or women. People with Addison's disease can lead normal lives as long as they take their medication. President John F. Kennedy had the condition.
In Addison's disease, called primary adrenal insufficiency, the adrenal glands don't make enough of a hormone called cortisol, or less often, a related hormone called aldosterone.
Cortisol's most important function is to help the body respond to stress. It also helps regulate your body's use of protein, carbohydrates, and fat; helps maintain blood pressure and cardiovascular function; and controls inflammation. Aldosterone helps your kidneys regulate the amount of salt and water in your body -- the main way you regulate blood volume and keep your blood pressure under control. When aldosterone levels drop too low, your kidneys cannot keep your salt and water levels in balance. This makes your blood pressure drop.
What Causes Addison's Disease?
Most cases of Addison’s disease result from a problem with the adrenal glands themselves (primary adrenal insufficiency). Autoimmune disease accounts for 70% of Addison’s disease. This occurs when the body's immune system mistakenly attacks the adrenal glands. This autoimmune assault destroys the outer layer of the glands.
Long-lasting infections -- such as tuberculosis, HIV, and some fungal infections -- can harm the adrenal glands. Cancer cells that spread from other parts of the body to the adrenal glands also can cause Addison's disease. Although rare, the adrenal glands can be injured as a result of a bacterial infection.
Less commonly, adrenal glands can be affected by "secondary adrenal insufficiency," which is caused by a problem with the pituitary gland or a problem with the hypothalamus, both located in the center of the brain. These glands produce hormones that act as a switch and can turn on or off the production of hormones in the rest of the body. A pituitary hormone called ACTH is the switch that turns on cortisol production in the adrenal gland. If ACTH levels are too low, the adrenal glands stay in the off position.
Another cause of secondary adrenal insufficiency is prolonged or improper use of steroid hormones such as prednisone. Less common causes include pituitary tumors and damage to the pituitary gland during surgery or radiation.