Exogenous Cushing's syndrome is a form of Cushing's syndrome caused by administration of glucocorticoid (also called corticosteroid) hormones, such as prednisone.
Alternative Names
Cushing's syndrome - corticosteroid induced; Corticosteroid-induced Cushing's syndrome; Iatrogenic Cushing's syndrome
Causes, incidence, and risk factors
Cushing's syndrome is named after the surgeon Harvey Cushing. It is a group of clinical signs and symptoms caused by a chronic excess of glucocorticoids, which are hormones produced by the adrenal glands. Glucocorticoids affect many body functions and are essential for survival, but when the level of these hormones is too high, it can cause serious problems. The most important glucocorticoid is the "stress hormone" cortisol. The pituitary gland, a small gland at the base of the brain, regulates cortisol production by secreting a hormone called adrenocorticotropic hormone (ACTH). Exogenous (i.e., caused by something outside the body) Cushing's syndrome is caused by administration of synthetic glucocorticoids, such as prednisone or dexamethasone, for therapeutic purposes (for example, to treat asthma).
Endogenous (i.e., caused by something within the body) Cushing's syndrome may be caused by ACTH-producing tumors of the pituitary gland (a condition called Cushing's disease), malignant tumors of other organs that produce ACTH, and cortisol-producing tumors of one or both of the adrenal glands.
Treatment
The suggested treatment is slow withdrawal of corticosteroid therapy under medical supervision. In situations where the medication cannot be discontinued because of the underlying disease (for example, if steroids are needed to treat severe asthma), every effort should be made to reduce the possibilty of developing complications. Excess glucocortoids can raise blood sugar and cholesterol levels, and increase bone loss.
High blood sugar should be treated aggressively with diet, oral medications, and/or insulin High cholesterol should be treated with diet and/or medications Most experts recommend treating patients who will be on steroids for longer than 4-6 weeks in with medication to prevent bone loss (e.g., bisphosphonates like alendronate or risedronate). This will reduce the risk of fracture.
Expectations (prognosis)
The effects of adrenal atrophy caused by chronic drug administration should be reversible by withdrawing the drug.
Complications
Cushing's syndrome symptoms can cause persistent discomfort. Steroids can cause diabetes and high cholesterol levels. If left untreated, both of these complications can increase the risk of heart attacks. Untreated high blood sugar over many years can cause damage to the eyes, kidneys and nerves. Cushing's syndrome can also lead to weak bones (osteoporosis) and increase the risk of fracture.
These complications can generally be prevented with proper treatment.
Calling your health care provider
Call for an appointment with your health care provider if you are taking a corticosteroid drug and you develop symptoms of Cushing's syndrome.
Prevention
Awareness of the signs and symptoms of Cushing's syndrome may permit early intervention for patients prescribed corticosteroids.