First described by Harvey Cushing in 1932, Cushing's Syndrome describes a characteristic set of clinical features and biochemical changes due to chronically raised levels of the glucocorticoid, cortisol.
Cushing's syndrome occurs in all races. It affects more women than men, in a ratio of 3 to 1. It mainly occurs in those between the ages of 20 and 60 years, and has an incidence of between 0.7 and 2.4 cases per million people each year.
It is important to draw attention to the distinction between Cushing's syndrome and Cushing's disease. Cushing's disease is one of the causes of Cushing's syndrome. It describes the excessive secretion of adrenocorticotrophic hormone (ACTH) by small benign tumours found in the anterior pituitary gland. The terms Cushing's disease and ACTH-dependent Cushing's syndrome are used synonymously.