What Is the Most Common Cause of Addison’s Disease?

Adrenal gland insufficiency causes Addison’s disease. The adrenal glands are small glands that sit on top of each of the kidneys and work under the direction of the pituitary gland in the brain. 

The pituitary gland produces adrenocorticotropic hormone (ACTH) which stimulates the adrenals to make mineralocorticoids, glucocorticoids, and androgens: three hormones necessary for the body to function.

When the adrenal glands fail to make these important hormones, it is called adrenal insufficiency. If the adrenal insufficiency is due to the adrenal gland not functioning properly (i.e., not making one or all the three of the important hormones) it is called “primary adrenal insufficiency,” also known as Addison’s disease.

Symptoms of Addison’s disease include: 

• patches of dark skin (hyperpigmentation),
• progressive weakness, 
• fatigue, 
• poor appetite, 
• weight loss, 
• nausea, 
• vomiting, 
• occasional diarrhea,
• dizziness (including dizziness on standing), 
• lightheadedness/fainting, 
• muscle pain, 
• joint pains,
• salt craving, 
• decreased insulin requirements and/or hypoglycemic episodes in diabetics, 
• impotence, 
• decreased libido, and
• missed menstrual periods.

An acute flare of Addison symptoms is called an acute adrenal crisis and symptoms include: 

• nausea, 
• vomiting, 
• low blood pressure,
• shock,
• bluish tinge to skin, 
• confusion, 
• high fever, and 
• coma. 

The most common cause of Addison’s disease is idiopathic autoimmune adrenocortical insufficiency. For some unknown reason the body attacks the adrenal glands, causing them to shrink and scar, and not produce sufficient adrenal hormones. Addison’s disease is often also associated with Hashimoto’s thyroiditis (also called Schmidt syndrome).

Other causes of chronic Addison’s disease include:

• Tuberculosis (TB)
• Cancer
• Hodgkin and non-Hodgkin lymphoma and leukemia
• AIDS
• Metabolic disorders such as amyloidosis and hemochromatosis
• Congenital adrenal hyperplasia
• Drug-related causes 
• Ketoconazole 
• Aminoglutethimide 
• Mitotane 
• Methadone

Causes of acute Addison’s disease (acute adrenal crisis):

• Stress or other acute illness
• Failure to increase steroids
• Bilateral adrenal hemorrhage
• Bilateral adrenal artery emboli and bilateral vein thrombosis (rare)
• Bilateral adrenalectomy for any reason

Addison’s disease is diagnosed with blood tests. These tests may include: 

• Blood cortisol levels
• Corticotropin (ACTH) levels

Usually performed in the morning, and abnormal levels may lead to further testing. 

Other lab tests may be recommended, including:

• Electrolytes, including sodium, potassium, and calcium
• Urinary sodium
• Kidney function testing (BUN and creatinine)
• Blood glucose level
• Live function tests 
• Complete blood count (CBC)
• Thyroid hormone levels
• Prolactin levels

Imaging studies may also be indicated, such as a chest X-ray and CT scan of the abdomen. 

Treatment for Addison’s disease usually involves medications to replace the hormones that are not being made by the adrenal gland.

These medications include:

• Glucocorticoids
• hydrocortisone 
• prednisone 
• Mineralocorticoids
• fludrocortisone 
• Androgens
• dehydroepiandrosterone (DHEA) 

If Addison’s disease is not properly managed, patients can experience adrenal crisis, which can result in shock, low blood pressure, high fever, coma, and even death.

If treated properly, people with Addison’s disease can have a normal life expectancy. Patients who experience adrenal crisis have a high rate of complications and can die from their disease.