Cushing's disease or hyperadrenocorticism is a disorder in which the body's adrenal glands produce abnormally large amounts of cortisol or other types of hormones in a rare form of the condition. Cushing's disease can be caused by a tumor within the pituitary gland that over-stimulates the adrenal glands, by a tumor within one of the adrenal glands itself or through the overuse of corticosteroid drugs. Middle-aged and older dogs are most frequently diagnosed with Cushing's disease.
Affected dogs often have tremendous appetites, drink and urinate more than normal and have poor quality coats, skin abnormalities and a pot-bellied appearance. A veterinarian may suspect the presence of Cushing's disease based on an animal's clinical signs and the results of routine blood work and a urinalysis, but specific tests like an ACTH stimulation test, are necessary to reach a definitive diagnosis. No test used to diagnose Cushing's disease is perfect, so don't be surprised if several need to be run before a final verdict is reached. Additional blood work or an abdominal ultrasound is usually necessary to determine whether the condition is caused by a pituitary or adrenal tumor.
The best choice for treatment depends on the source of an animal's Cushing's disease. Dogs receiving corticosteroids need to be slowly tapered off these medications. Adrenal tumors can be surgically removed, which will be curative in many instances. Dogs with the more common pituitary form of the disease are usually treated with one of several different drugs or drug combinations that suppress adrenal function. Life-long therapy is necessary in these cases, and dogs must be closely monitored for potential side effects of the treatment. Most dogs with Cushing's disease can live long and happy lives while their conditions are successfully held in check.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008