Adrenal Insufficiency &
Addison's Disease

What is adrenal insufficiency?

Adrenal insufficiency is a condition characterized by inadequate production of the adrenal hormones cortisol and aldosterone. The adrenal glands are small organs located on top of each kidney. They consist of an inner layer called the adrenal medulla and an outer layer called the adrenal cortex. Each layer produces several different hormones that control many body systems. Hormone production is regulated by interactions between the hypothalamus, the pituitary gland, and the adrenal glands. If any part of their signaling and feedback system is not working, it can cause major disruptions and illness within the body. Primary adrenal insufficiency, also called Addison's disease, affects the levels of both cortisol and aldosterone. It is caused by underactive or damaged adrenal glands. Secondary adrenal insufficiency is the result of a pituitary dysfunction and typically affects only cortisol production.

Cortisol is a glucocorticoid hormone, produced by the adrenal cortex. Among its many roles, cortisol affects the metabolism of carbohydrates, proteins, and fats, affects glucose levels in the blood, acts as an anti-inflammatory agent, and helps the body react to stress. Aldosterone, a mineralocorticoid hormone that is also produced by the adrenal cortex, manages the salt and potassium balance in the blood. Without enough of these two hormones, the body becomes weak and dehydrated, unable to maintain an adequate blood pressure or to respond properly to stress.

Addison's disease affects about 1 to 4 people per 100,000 in the U.S. It is found in patients of all ages and affects both males and females equally. Symptoms of insufficiency may not emerge until about 80% to 90% of the adrenal cortex has been destroyed.

In the U.S., about 70% of primary adrenal insufficiency in adults is due to an autoimmune process. About 30% of the time, the adrenal damage is due to other causes, such as: tuberculosis, a common cause in areas of the world where tuberculosis is more prevalent; bacterial, viral and fungal infections; adrenal hemorrhage; and the spread of cancer into the adrenal glands. Rarely, it may be due to a genetic abnormality of the adrenal glands. In children, about 70% of cases are caused by a congenital disease termed congenital adrenal hyperplasia, while 30% of the time adrenal damage is due to autoimmune disease, another inherited disease termed adrenoleukodystrophy, or less common causes.

Secondary adrenal insufficiency is due to a decrease in the production of the pituitary hormone ACTH (adrenocorticotropic hormone). ACTH is a pituitary messenger - it tells the adrenal cortex to produce cortisol. If there is insufficient ACTH, due to pituitary damage, a pituitary tumor, or some other cause, then cortisol production is not stimulated. Secondary adrenal insufficiency can also arise when corticosteroid therapy (such as prednisone, which may be given to relieve inflammation in conditions such as rheumatoid arthritis) is abruptly halted. These Treatment suppress natural cortisol production, and it can take several weeks or months for normal production to resume. With secondary adrenal insufficiency, aldosterone production is usually not affected.