Cushing’s Disease – A First Hand Veterinary Perspective

Is my dog just getting old (or could there be something else going on)???

Have you noticed that your middle aged or older dog is starting to slow down? Is he lethargic, maybe panting more, getting up at night to urinate? Drinking more water, have thinning fur, and a pot belly? He’s just getting old, right? After all, his appetite is great and he’s not losing weight…

Does this sound like it could be describing your dog? While it sure sounds like typical signs of aging, these vague symptoms could indicate that your dog has Cushing’s Disease.

What is Canine Cushing’s Disease?

Technically it’s called Hyperadrenocorticism, but ever since it was described in humans by Dr. Cushing back in 1932, it is now commonly called Cushing’s Disease. This disease causes the body to overproduce cortisol, which has secondary effects on the rest of the body. It is seen in middle aged to older dogs, and has such a gradual onset that the symptoms are often mistaken for typical aging. It is very rare in cats.

There are two main forms of Cushing’s Disease: adrenal and pituitary.

Pituitary Cushing’s Disease in Dogs

The first and most common, is the result of a benign tumor located on the pituitary gland in the brain. The pituitary gland, often called the ‘master gland,’ produces hormones that signal other organs in the body to produce their hormones.

In Cushing’s Disease, the tumor produces excessive ACTH which causes the adrenal glands (which are located in the abdomen next to the kidneys) to produce excessive amounts of cortisol. Some cortisol is necessary for life, but excessive amounts are detrimental.

Adrenal Cushing’s Disease in Dogs

The second form of Cushing’s Disease involves a tumor directly on one of the adrenal glands that causes the gland to overproduce cortisol. In general, half of these tumors are benign, and half are malignant.

(A third form of the disease can be seen in dogs treated with excessive doses of steroids.)

The majority of canine Cushing’s cases (80 to 85%) are a result of tumors of the pituitary gland.

Identifying Cushing’s Disease

Diagnosing Cushing’s Disease starts by your veterinarian taking a thorough history and doing a physical exam on your dog. If his symptoms support Cushing’s Disease, your veterinarian will want to run blood and urine tests to rule in or out other diseases and look for changes in support of Cushing’s Disease. Finally a Cushing’s-specific test is done to help identify if your pet has the disease. Sometimes an abdominal ultrasound is needed as well.

Treating Cushing’s Disease

Because the majority of Cushing’s cases are pituitary-based, the majority of them are treated with oral medication. Newer medication now available makes treatment much safer and easier than those medications used in the past.

For adrenal-based Cushing’s disease, if the adrenal tumor can’t be surgically removed, oral medication is also used.

Oral treatment is long term and must be accompanied by regular veterinary monitoring.

So if it seems like your dog is prematurely old and exhibiting these symptoms, discuss with your veterinarian if testing should be done.

Luckily, Cushing’s Disease can be diagnosed and symptoms effectively controlled in the majority of dogs, restoring vitality and helping your dog to once again lead an active happy life.