ADDISON'S DISEASE

Addison's disease occurs when the two small glands sitting atop the kidneys, called the adrenal glands, fail to produce enough cortisol. Cortisol is a hormone that circulates in the bloodstream and is important for maintaining normal blood pressure and metabolism. Cortisol levels are regulated by a hormone secreted from the pituitary gland in the head called adrenocorticotropic hormone (ACTH).

There are three main reasons for low cortisol levels: adrenal failure (Addison's disease), pituitary failure (low ACTH), or suppression of the normal response caused by medications. Most commonly, adrenal failure is caused by destruction of the adrenal cortex, or outer shell, by the body's own immune system. Doctors are not sure why this occurs. Other causes include infections that spread to the bloodstream, including tuberculosis or fungus infections. Cancer that has spread to the adrenal glands may also cause Addison's disease. Pituitary failure may result from local tumor growth and compression, or from pituitary surgery. Medications such as oral steroids taken for asthma, bronchitis, or arthritis may cause a temporary shutting off of normal cortisol response, especially if doses are rapidly withdrawn.

Addison's disease is relatively rare, affecting only 1 of every 100,000 individuals. Addison's disease is best detected by a complete medical history and physical examination, followed by an ACTH stimulation test. This test involves injection of ACTH into the muscle, with the measurement of blood cortisol before the test and 60 minutes later. In addition, ACTH hormone levels and aldosterone levels may be drawn. The diagnosis is established with a subnormal cortisol response to the administered ACTH. Elevated ACTH levels and suppressed aldosterone levels confirm the diagnosis of Addison's disease.

There is no cure for Addison's disease; however, it is treatable with oral medicines.

Patients typically complain of tiredness, weakness, decreased appetite, depression, or weight loss. Some may have nausea, vomiting, and diarrhea. The skin and mucous membranes may become hyperpigmented. This is especially notable on the creases of the palm. Other patients may have no symptoms.

Addison's disease may cause low blood pressure, especially during times of stress or on standing. This can lead to dizziness and fainting. Addisonian crisis is a medical emergency manifested by cardiovascular collapse and associated with back pain, severe nausea, vomiting, and diarrhea. This may occur suddenly in response to severe stress, trauma, or illness.

Treatment of acute Addisonian crisis involves intravenous fluids and glucose plus intravenous steroids such as dexamethasone. Chronic treatment involves oral glucocorticoid replacement with hydrocortisone. Fludrocortisone is also available for patients with low aldosterone levels. In addition, a high-salt diet is often helpful.

Overtreatment with hydrocortisone could lead to the Cushing's syndrome, which involves weight gain and change in body habitus caused by extra steroids circulating in the blood. High blood pressure or diabetes may result from excess hormone replacement. Undertreatment leaves patients feeling weak and tired.

• Carry injectable cortisol (Solu-Cortef) for emergency purposes and have someone in your family learn to administer this medicine for you in case you are too ill to give yourself medicine.
• Get a Medic Alert bracelet which states that you have Addison's disease and require cortisol in emergencies.
• Increase your hydrocortisone dose if you notice a fever or if you have decreased oral intake caused by mild gastrointestinal illness.
• Call your doctor whenever you feel poorly.

• Don't skip doses of your medicine, especially if you are feeling sick.
• Don't forget to take your medicine, and make sure you don't run out of medicine.
• Don't be afraid to slowly decrease your medicine if your doctor recommends a lower dose. After an initial adjustment period, you will continue to feel well and will avoid complications from overtreatment such as weight gain, diabetes, and high blood pressure.

• You are having nausea and vomiting or a fever.
• You have elective surgery scheduled; the dose of your medicines needs to be adjusted.
• You feel weak and tired and have noticed weight loss.
• You or your family members do not know how to inject cortisol in an emergency.

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