What Is Addison's Disease?
Addison's disease is a medical condition in which the adrenal glands stop making hormones important for certain bodily functions. Addison's disease is characterized by weight loss, muscle weakness, fatigue, low
blood pressure, and sometimes darkening of the skin in both exposed and non-exposed parts of the body.
The late President John F. Kennedy had Addison's disease. Addison's disease affects about 1 in 100,000 people.
Understanding the Adrenal Glands
There are two adrenal glands, one above each kidney in the back of the upper abdomen. The adrenal glands are also called the suprarenal glands. The inside layer of the adrenal gland is called the adrenal medulla. The adrenal medulla produces epinephrine (adrenaline). The outside layer is called the adrenal cortex. The cells in the adrenal cortex make two important hormones that help the body function properly. The two hormones are cortisol and aldosterone.
Cortisol
Cortisol belongs to a class of hormones called glucocorticoids, which affect almost every organ and tissue in the body. Scientists think that cortisol has possibly hundreds of effects in the body. Cortisol's most important job is to help the body respond to stress. Among its other vital tasks, cortisol helps:
- Maintain blood pressure and cardiovascular function
- Slow the immune system's inflammatory response
- Balance the effects of insulin in breaking down sugar for energy
- Regulate the metabolism of proteins, carbohydrates, and fats
- Maintain proper arousal and sense of well-being.
Because cortisol is so vital to health, the amount of cortisol produced by the adrenals is precisely balanced.
Aldosterone
Aldosterone belongs to a class of hormones called mineralocorticoids, also produced by the adrenal glands. Aldosterone helps maintain
blood pressure and water and salt balance in the body by helping the kidney retain sodium and excrete potassium. When aldosterone production falls too low, the kidneys are not able to regulate salt and water balance, causing blood volume and blood pressure to drop.
What Causes Addison's Disease?
Addison's disease occurs due to the destruction of the adrenal cortex. As a result, both cortisol and aldosterone hormones are often lacking.
Addison's disease symptoms usually begin when at least 90 percent of the adrenal cortex has been destroyed.
In about 70 percent of Addison's disease cases, the destruction of the adrenal cortex is caused by the body's own immune system (
autoimmune disease). Normally the immune system protects the body against infection and disease. In an
autoimmune disease, the body's immune system mistakenly attacks some part of the body. In Addison's disease, the immune system attacks the adrenal cortex. Why the immune system attacks the adrenal cortex is unknown.
Other causes of Addison's disease can include:
(Click Causes of Addison's Disease for more information.)
- Chronic fatigue that progressively worsens.
- Muscle weakness.
- Loss of appetite.
- Weight loss.
- Nausea.
- Vomiting.
- Diarrhea.
- Low blood pressure that falls further when standing, causing dizziness or fainting.
- Skin changes with areas of hyperpigmentation, or dark tanning, covering exposed and non-exposed parts of the body. This darkening of the skin is most visible on scars, skin folds, pressure points (such as the elbows, knees, knuckles, and toes), lips, and mucous membranes.
Diagnosing Addison's Disease
In its early stages, it can be difficult to make an Addison's disease diagnosis. After asking a number of questions and performing a physical exam, the doctor may recommend certain tests as part of
Addison's disease testing. These Addison's disease tests can include:
- ACTH stimulation test
- CRH stimulation test
- ACTH and cortisol blood levels
- Abdominal x-rays.
(Click Diagnosing Addison's Disease for more information.)
There is no Addison's disease cure. However, Addison's disease can be controlled with medications. Treatment involves replacing, or substituting, the hormones that the adrenal glands are not making.
Most people with Addison's disease should expect to lead healthy lives with a normal life expectancy.
Because the
symptoms of Addison's disease progress slowly, they are usually ignored until a stressful event like an illness or an accident causes them to become worse. This is called an
addisonian crisis, or acute
adrenal insufficiency. In most cases, symptoms are severe enough that patients seek medical treatment before a crisis occurs. However, in about 25 percent of patients, symptoms of Addison's disease first appear during an addisonian crisis.
An addisonian crisis can cause life-threatening complications unless immediate treatment is provided.
Living With Addison's Disease
People with Addison's disease should learn as much as possible about their disease and about situations that can cause a hormone deficiency. People should also talk with their friends and family
about Addison's disease. Recognizing early warning signs of an addisonian crisis (and learning about ways to minimize the effects of such a crisis) will help people live healthy lives.
