Cushing's syndrome

Cushing's syndrome (also called hypercortisolism or hyperadrenocorticism) is an endocrine disorder caused by high levels of cortisol in the blood from a variety of causes, including primary pituitary adenoma (known as Cushing's disease), primary adrenal hyperplasia or neoplasia, ectopic ACTH production (e.g., from a small cell lung cancer), and iatrogenic (steroid use). Normally, cortisol is released from the adrenal gland in response to ACTH being released from the pituitary gland. Both Cushing's syndrome and Cushing's disease are characterized by elevated levels of cortisol in the blood, but the cause of elevated cortisol differs between the two. Cushing's disease specifically refers to a tumor in the pituitary gland that stimulates excessive release of cortisol from the adrenal gland by releasing large amounts of ACTH. In Cushing's syndrome, ACTH levels will normally drop due to negative feedback from the high levels of cortisol. Cushing's disease was discovered by American physician, surgeon and endocrinologist Harvey Cushing (1869-1939) and reported by him in 1932.

Cushing's syndrome--which is also a relatively common condition in domestic dogs and horses--is characterised by abnormal fat deposition. (The syndrome in horses leads to weight loss, polyuria and polydipsia and may cause laminitis.)