Definition of Addison's disease:

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

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.