Addison's Disease

Adrenal gland insufficiency

Addison's disease is a disorder of the adrenal glands. These two glands are located above each kidney. The outer layers of the glands produce cortisol and aldosterone, two of the body's essential hormones (chemicals). The gradual destruction of those outer layers during the disease causes less and less of those hormones to be produced, with serious effects resulting in the body.

What causes it?
Most cases of Addison's disease (about 70%) are caused by an autoimmune disorder, in which the body's antibodies attack healthy tissues. Other, more rare, causes of destruction of the adrenal glands may be:

• Tuberculosis (about 20% of cases)
• Chronic infections, such as fungal infections
• Invasion of the adrenal glands by cancer cells from another part of the body
• Amyloidosis (protein deposits)
• Adrenoleukodystrophy (a neurological disorder)
• Surgical removal of both adrenal glands

Addison's disease may also be caused when other hormones in the body, such as ACTH, are out of balance. In these cases the tissues of the adrenal gland are not destroyed.

What are the symptoms?
Since the destruction of the glands is gradual, the symptoms usually come on slowly. Typical symptoms would be:

• Chronic, worsening fatigue and muscle weakness
• Loss of appetite
• Weight loss
• Nausea, vomiting, and diarrhea (50% of cases)
• Low blood pressure, causing dizziness when standing up
• Irritability and depression
• Salt craving
• Darkening of the skin, most visible on skin folds, elbows, knees, knuckles, and toes. The person may look as if he/she has a suntan.

Addisonian crisis (acute adrenal insufficiency)
Unfortunately, since the symptoms come on gradually, they may be ignored or missed. A dramatic change for the worse in symptoms will occur, however, when a stressful event like illness or accident occurs. This is called Addisonian crisis, or acute adrenal insufficiency, and is a medical emergency. Symptoms of a crisis include sudden pain in the lower back, abdomen, or legs, and severe vomiting and diarrhea, which can progress to dehydration and loss of consciousness.

How is Addison's disease diagnosed?
Laboratory tests can confirm the diagnosis of Addison's disease. Regular blood tests may show increased blood potassium or low blood sodium. The definitive test for the disease is called ACTH stimulation. The hormone ACTH, when injected, should make the person's blood levels of cortisol and aldosterone rise. The person with Addison's disease isn't able to make enough of those hormones, so their blood levels don't rise sufficiently.

How is it treated?
Treatment focuses on replacing the insufficient hormones. Daily replacement medication is taken for the rest of the person's life. Regular checkups to monitor the disease are important. Usually the person with Addison's disease sees an endocrinologist (a physician who specializes in hormonal disorders).

Information for this article was taken from:
- National Adrenal Disorders Foundation. Addison's Disease: The Facts You Need to Know.
- National Institute for Diabetes & Digestive & Kidney Diseases. Addison's Disease.