Canine (dog) Cushing's Disease - What Owners Need to Know

Veterinarians more accurately refer to Cushing's disease as hyperadrenocorticism, which causes too much adrenal hormone to be produced. Cushing's disease can occur naturally or can be due to over use of corticosteroids such as prednisone.
Having experienced Cushing's disease with one of our dogs it was necessary to understand the symptoms, diagnosis, and treatment of Cushing's disease. Here, is what my family learned about Cushing's disease.

Symptoms

Increased drinking, thirst, urination, appetite, panting, hair loss, and high-blood pressure are some of the signs of Cushing's disease. Hair loss is normally distributed evenly on both sides of the dog's body. Other symptoms can be pendulous belly, thin skin, calcified lumps in the muscle and skin, signs of diabetes, and weakening of the skeletal muscles and heart, along with nervous system diseases.

Diagnosis

To diagnose Cushing's disease, the veterinarian will need to perform several blood tests. The first test in this diagnosis is a normal blood panel. To further confirm Cushing's the veterinarian may perform a test known as a low dose dexamethasone test. This is a test consisting of taking a baseline blood sampling in the morning, injecting dexamethasone and then a follow-up blood test 8 hours later. A normal dog will have the dexamethasone suppress cortisol levels in the blood stream. If the dog has Cushing's disease, this effect does not occur. Once the diagnosis is confirmed, it will be possible for the veterinarian to distinguish between adrenal tumors and pituitary gland tumors with a second test. The high dose dexamethasone suppression test can be performed to recognize the difference in adrenal and pituitary tumors. Many dogs with pituitary tumors will have cortisol suppression with this test. There are other tests that may need to be performed, ACTH response test, urine cortisol/creatinine ratios X-rays and ultrasonography can also help to determine if an adrenal gland tumor is present.

Treatment

If there is an adrenal gland tumor, it can be removed surgically. A specialist, due to the dangers involved with the surgical procedure, most often does the removal of this tumor. Pituitary gland tumors are not usually removed, but treated using lysodren or ketaconazole. Deprenyl for the treatment of Pituitary gland tumors has also been done. Lysodren kills the outer layer of the adrenal gland if administered in proper amounts. It will be required if this treatment program is in place, for close supervision of lysodren by performing periodic blood tests. Lysodren can have adverse affects, but it is the standard treatment at this time.

Lysodren can cause, diarrhea, lethargy, weakness, and lowered appetite. Vomiting can also occur with the treatment of lysodren. If these signs appear then, the veterinarian should be immediately notified and consulted.

Treatment for pituitary tumors is symptomatic therapy. This treatment will not cure the pituitary tumor, however, the lifespan of the dogs diagnosed with Cushing's with or without treatment is approximately two years.

Cushing's disease caused from over treatment by glucocorticoid for chronic conditions such as skin or food allergies can be treated very simply. Treatment for this form of Cushing's is simply tapering doses of the medication every-other day until the medication is no longer being used. If you have a dog being treatment by glucocorticoid for a chronic condition talk with your veterinarian regarding the treatment program and the chances of Cushing's showing up later in the life of your pet.

Resources:

Monetvilla Veterinarian Clinic, Portland, Oregon

http://www.vetinfo.com/dcushing.html
http://www.kateconnick.com/library/cushingsdisease.html