What causes hyperadrenocorticism?
Most cases of hyperadrenocorticism are caused by enlargement of the adrenal cortex. The enlargement may be caused by tumours of the adrenal gland that produce adrenal hormones (15% of cases) or of the pituitary gland (located in the brain) that produce excessive ACTH, a hormone which stimulates the adrenal gland to produce corticosteroids – this form of the disease is referred to as pituitary-dependent hyperadrenocorticism and accounts for around 85% of cases. The tumours can be benign or malignant (cancerous). The signs of hyperadrenocorticism can also be produced by the long-term, daily administration of large doses of corticosteroids. When this occurs, the disease is called “iatrogenic hyperadrenocorticism.
