Secondary adrenocortical insufficiency

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Secondary adrenocortical insufficiency

Secondary adrenocortical insufficiency is a condition in which a deficiency of adrenocorticotropic hormone (ACTH) leads to insufficient cortisol production.

Production of cortisol is controlled by the action of ACTH produced by the pituitary gland. The pituitary gland is regulated by the hypothalamus in the brain. If either the brain or pituitary gland is damaged, less ACTH is produced, leading to underfunctioning of the adrenal glands and reduced cortisol production.

This may be caused by:

• A tumor of the pituitary gland.
• Previous radiation of the hypothalamus or pituitary gland.
• Previous surgery to the pituitary gland.
• Medium- to long-term use (several weeks) of corticosteroid medication.
• Rare conditions such as hemochromatosis, sarcoidosis, or Sheehan's syndrome (hypopituitarism). Sheehan's syndrome is occasionally caused by severe blood loss after delivering a baby.

The symptoms of secondary adrenocortical insufficiency are similar to those of Addison's disease, except that darkening of the skin (hyperpigmentation) and high levels of potassium in the blood are not present. Symptoms include:

• Fatigue and muscle weakness that gradually become worse over time.
• Weight loss. Profound weight loss is a prominent symptom.
• Loss of appetite.

Diagnosis starts with a medical history and physical examination. If your health professional suspects adrenal insufficiency, he or she will check your blood cortisol and ACTH levels. Your doctor may recommend imaging tests of the adrenal glands, the pituitary gland, or the hypothalamus. If the diagnosis is still not clear, an ACTH stimulation test is done: You will be given a man-made form of ACTH to see whether your body creates cortisol. A low level of cortisol after an injection of ACTH indicates adrenal insufficiency. Further tests will show whether you have primary adrenocortical insufficiency (Addison's disease) or secondary adrenocortical insufficiency. Your doctor may start treatment during the testing if he or she thinks adrenal insufficiency is likely. Treatment can then be stopped if it is found to be unnecessary after testing is complete.

Computerized axial tomography (CAT scan) or magnetic resonance imaging (MRI) can be used to see whether there is evidence of damage to the brain or pituitary gland (such as a tumor) that is causing adrenal failure.

Treatment for secondary adrenocortical insufficiency consists of cortisol replacement and treatment of the underlying cause, if possible.

Credits

Last updated:	March 23, 2006
Author:	Shannon Erstad, MBA/MPH
Reviewed By:	Kathleen Romito, MD - Family Medicine, Alan C. Dalkin, MD - Endocrinology
Editors:	Kathleen M. Ariss, MS, Pat Truman