What IS Cushings Disease?
[ILLUSTRATION OMITTED] Your cat Pinky has enjoyed good health for most of the eight years she’s spent in your home. Lately, however, she’s been undergoing some worrisome changes. She’s eating and drinking much more than she used to; she’s recently begun to develop a potbelly; and she’s become uncharacteristically lethargic. While such changes could be attributable at least in part to her advancing age, they are also signs that Pinky could be afflicted with a disorder called hyper-adrenocorticism, otherwise known as Cushing’s disease. According to Deb Zoran, DVM, PhD, …
Cushing’s Disease (Hyperadrenocorticism) is caused by deleterious effects of high circulating cortisol concentrations on multiple organ systems. Spontaneous hyperadrenocorticism is caused by excessive production of cortisol by the adrenal cortex of the adrenal gland. It is caused either by: 1. Pituitary gland adenoma (tumor) or hyperplasia 2. Adrenal gland tumor 3. The administration of too much glucocorticoids (steroids) at too high a dose. The key to understanding the treatment is understanding the cause. Several new screening tests are now available. There is also a new drug ( L-deprenyl) available to treat Cushings – but its long term use and safety is not recorded. The drug of choice is mitotane. Depending on the cause and problem, clinical signs should resolve within several days to months. Untreated the disease is generally progressive with a poor prognosis. With treatment especially for Pituitary dependent hyperadrenocorticism (PDH) the disease has a good prognosis. The average
In the normal body, the pituitary gland, located at the base of the brain, can detect when cortisol levels in the blood are declining. In response, the pituitary secretes a stimulating substance which causes the adrenal gland to release more cortisol. When the pituitary gland detects that cortisol levels are again appropriate, it stops its stimulatory message. You can think of the pituitary gland as a sort of a thermostat for cortisol. This raising and lowering of cortisol blood level is regulated throughout the day and occurs rapidly. PITUITARY-DEPENDENT CUSHING’S SYNDROME This accounts for 85% of dogs with Cushing’s syndrome. Basically, the pituitary gland grows a tumor, generally microscopic and generally benign. This tumor, however, over-produces its stimulatory message thus leading to enlargement of both adrenal glands and an over-production of cortisone. Occasionally (10% of pituitary-dependent Cushing’s dogs), these benign pituitary tumors are large enough to compress the brain.
