Addison's disease

Definition

Addison's disease is a disorder that occurs when the adrenal glands do not produce enough of their hormones.

Alternative Names

Adrenocortical hypofunction; Chronic adrenocortical insufficiency; Primary adrenal insufficiency

Causes, incidence, and risk factors

The adrenal glands are small hormone-secreting organs located on top of each kidney. They consist of the outer portion (called the cortex) and the inner portion (called the medulla).

The cortex produces three types of hormones:

• The glucocorticoid hormones (such as cortisol) maintain sugar (glucose) control, decrease (suppress) immune response, and help the body respond to stress.
• The mineralocorticoid hormones (such as aldosterone) regulate sodium and potassium balance.
• The sex hormones, androgens (male) and estrogens (female), affect sexual development and sex drive.

Addison's disease results from damage to the adrenal cortex. The damage causes the cortex to produce less of its hormones.

This damage may be caused by the following:

• The immune system mistakenly attacking the gland (autoimmune disease)
• Infections such as tuberculosis, HIV, or fungal infections
• Hemorrhage, blood loss
• Tumors
• Use of blood-thinning drugs (anticoagulants)

Risk factors for the autoimmune type of Addison's disease include other autoimmune diseases:

• Chronic thyroiditis
• Dermatis herpetiformis
• Graves' disease
• Hypoparathyroidism
• Hypopituitarism
• Myasthenia gravis
• Pernicious anemia
• Testicular dysfunction
• Type I diabetes
• Vitiligo

Certain genetic defects may cause these conditions.

Symptoms

• Changes in blood pressure or heart rate
• Chronic diarrhea
• Darkening of the skin - patchy skin color
• Unnaturally dark color in some places
• Paleness
• Extreme weakness
• Fatigue
• Loss of appetite
• Mouth lesions on the inside of a cheek (buccal mucosa)
• Nausea and vomiting
• Salt craving
• Slow, sluggish movement
• Unintentional weight loss

Signs and tests

Tests may show:

• Increased potassium
• Low blood pressure
• Low cortisol level
• Low serum sodium
• Normal sex hormone levels

Other tests may include:

• Abdominal x-ray
• Abdominal CT scan

This disease may also change the results of the following tests:

• 17-hydroxycorticosteroids
• 17-ketosteroids
• 24-hour urinary aldosterone excretion rate
• ACTH
• Aldosterone
• Blood eosinophil count
• CO2
• Cortrosyn stimulation test
• Potassium test
• Renin
• Urine cortisol

Treatment

Treatment with replacement corticosteroids will control the symptoms of this disease. However, you will usually need to take these drugs for life. People often receive a combination of glucocorticoids (cortisone or hydrocortisone) and mineralocorticoids (fludrocortisone).

Never skip doses of your medication for this condition, because life-threatening reactions may occur.

The health care provider may increase the medication dose in times of:

• Infection
• Injury
• Stress

During an extreme form of adrenal insufficiency, adrenal crisis, you must inject hydrocortisone immediately. Supportive treatment for low blood pressure is usually needed as well.

Some people with Addison's disease are taught to give themselves an emergency injection of hydrocortisone during stressful situations. It is important for you to always carry a medical identification card that states the type of medication and the proper dose needed in case of an emergency. Additionally, your health care provider may advise you to always wear a Medic-Alert tag (such as a bracelet) alerting health care professionals that you have this condition in case of emergency.

Expectations (prognosis)

With hormone replacement therapy, most people with Addison's disease are able to lead normal lives.

Complications

Complications can occur if you take too little or too much adrenal hormone supplement.

Complications also may result from the following related illnesses:

• Diabetes
• Hashimoto's thyroiditis (chronic thyroiditis)
• Hypoparathyroidism
• Ovarian hypofunction or testicular failure
• Pernicious anemia
• Thyrotoxicosis

Calling your health care provider

Call your health care provider if:

• You are unable to keep your medication down due to vomiting.
• You have been diagnosed with Addison's disease, and you have stress such as infection, injury, trauma, or dehydration. You may need to have your medication adjusted.
• Your weight increases over time.
• Your ankles begin to swell.
• You develop other new symptoms.

If you have symptoms of adrenal crisis, give yourself an emergency injection of your prescribed medication. If it is not available, go to the nearest emergency room or call 911.

Symptoms of adrenal crisis include:

• Abdominal pain
• Difficulty breathing
• Low blood pressure
• Reduced consciousness

References

Stewart PM. The adrenal cortex. In: Kronenberg H, Melmed S, Polonsky K, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, PA: Saunders Elsevier; 2008:chap 14.