ADDISON DISEASE

also called hypocortisolism or chronic adrenal insufficiency a rare disorder defined by destruction of the outer layer of the adrenal glands, the hormone-producing organs located just above the kidneys. The adrenal cortex produces numerous hormones called corticosteroids, which are involved in important functions of the body such as regulation of metabolism, blood pressure, and sodium and potassium levels. Damage to the cortex disrupts the production of two of these hormones, cortisol and aldosterone, leading to a variety of symptoms, including weakness, abnormal pigmentation of the skin and mucous membranes, weight loss, low blood pressure, emotional instability, and gastrointestinal upset. Ninety percent of the cortex usually is destroyed before these symptoms become apparent. In the mid-19th century when the English physician Thomas Addison first described the clinical features of the disease, the destruction of the adrenal cortex was attributed to tuberculosis. Today, worldwide, tuberculosis is still a cause of the disease; in developed countries, however, about 70 percent of cases result from an autoimmune reaction, an inappropriate attack launched by the immune system against, in this case, the adrenal glands. Addison disease also can be caused by fungal infections or cancer. Hormone replacement therapy will control the symptoms of the disease, but the treatment must be continued throughout life.