Definition of Cushing syndrome

Cushing syndrome: The constellation of symptoms and signs caused by an excess of cortisol hormone.

Cushing syndrome is an extremely complex hormonal condition that involves many areas of the body. Common symptoms are thinning of the skin, weakness, weight gain, bruising, hypertension, diabetes, thin weak bones (osteoporosis), facial puffiness and, in women, cessation of menstrual periods.

Ironically, one of the most common causes of Cushing syndrome is the administration of "cortisol-like medications" for the treatment of diverse diseases. All other cases of Cushing syndrome are due to the excess production of cortisol by the adrenal gland as, for example, due to:

1. An abnormal growth of the pituitary gland, which can stimulate the adrenal gland;
2. A benign or malignant growth within the adrenal gland itself, which produces cortisol; or
3. Production within another part of the body (ectopic production) of a hormone that directly or indirectly stimulates the adrenal gland to make cortisol.

The neurosurgeon Harvey Cushing (1869-1939) described excessive production of cortisol by the adrenal gland due specifically to an ACTH-secreting pituitary adenoma, a benign pituitary tumor that puts out ACTH (AdrenoCorticoTropic Hormone). This drives the adrenal gland to overproduce cortisol.