Addison’s disease

A rare chronic disorder in which there is a deficiency of the corticosteroid hormones hydrocortisone and aldosterone, normally produced by the adrenal cortex (the outer part of the adrenal glands). Excessive amounts of ACTH are secreted by the pituitary gland in an attempt to increase output of the corticosteroid hormones. Secretion and activity of another hormone, melanocyte stimulating hormone (MSH), is also increased. Addison’s disease can be caused by any disease that destroys the adrenal cortices. The most common cause is an autoimmune disorder in which the immune system produces antibodies that attack the adrenal glands. Symptoms generally develop gradually over months or years, and include tiredness, weakness, abdominal pain, and weight loss. Excess MSH may cause darkening of the skin in the creases of the palms, pressure areas of the body, and the mouth. Acute episodes, called Addisonian crises, brought on by infection, injury, or other stresses, can also occur. The symptoms of these include extreme muscle weakness, dehydration, hypotension (low blood pressure), confusion, and coma. Hypoglycaemia (low blood glucose) also occurs. Life-long corticosteroid drug treatment is needed. Treatment of Addisonian crises involves rapid infusion of saline and glucose, and supplementary doses of corticosteroid hormones.