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 (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 (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.
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