DEFINITION:

Cushing's disease creates a severe hormonal disturbance, affecting nearly every system in the human body. It is usually caused by an ACTH-secreting pituitary gland tumor, which results in the adrenal glands producing too much cortisol. Less commonly, a tumor or hyperplasia (overgrowth) of the adrenal glands may be the culprit. There are cases where ectopic-ACTH tumors (such as small cell lung cancer) can cause Cushing's. Even more rarely the cause may stem from hypothalmic dysfunction, with over-secretion of CRH. But the clinical manifestations are basically the same whatever the cause. With regard to pituitary tumors, these type are the rarest, and have the most detrimental long-term medical side effects.