Your pet doesn’t show her typical zest: She’s panting more than usual, drinking and urinating more often, always hungry. These symptoms could apply to many conditions, but one of them is Cushing’s disease. The good news is, it’s often treatable, and your pet can have a normal lifespan.
Cushing’s Disease Takes Two Forms
Cushing’s disease (also known as hyperadrenocorticism) occurs in pets (and humans) when the body produces too much cortisol. That hormone, which comes out of the adrenal glands, does a lot of good: It keeps inflammation down, regulates blood pressure, increases blood sugar and more. However, too much cortisol can cause anything from excessive appetite, thirst and urination, to muscle weakness, as well as skin and coat changes.
Veterinarians describe Cushing’s as a “naturally occurring” condition when the body makes too much cortisol. Often there is a benign tumor that grows in the tiny pituitary gland, known as the “master gland” because it regulates the thyroid, adrenals, and other glands; this creates pituitary-dependent hyperadrenocorticism (HAC). Or a tumor grows in the adrenal glands, leading to adrenal-dependent HAC.
A pituitary tumor causes excessive production of adrenocorticotropic hormone (ACTH), which tells the adrenal glands to churn out excessive cortisol. An adrenal tumor simply secretes too much cortisol by itself. Pituitary tumors account for 80 to 85 percent of these cases.
Vets speak of “iatrogenic” Cushing’s when the glands produce normal amounts of cortisol, but an animal gets an overload by taking steroids in oral or injectable medications. Clinical signs remain the same for both types of Cushing’s.
What Are the Warning Signs of Cushing’s?
Vets refer to the five P’s: polyuria and polydipsia (increased urination and drinking), polyphagia (excessive hunger), panting, and a pot belly appearance. Owners may notice changes in the skin and coat, such as symmetrical hair loss on the body or a thinner skin. Less common to rare signs include lethargy, skin infections, urinary tract infections, diabetes that’s difficult to regulate, cruciate ligament rupture, facial nerve paralysis and pulmonary thromboembolism (clots).
Cushing’s rarely appears in dogs under 6 years old, and the mean age is 8 to 12 years. Small breeds are more prone to the pituitary-dependent form, and medium to large breeds account for about half of the adrenal-dependent form. Some studies suggest females face more risk than males. Dogs with Cushing’s usually remain happy and interact well with owners.
By the way, cats seldom get Cushing’s, and they usually present instead for concurrent conditions such as unregulated diabetes. Affected cats are often lethargic, become withdrawn and develop fragile skin.
Medicine vs. Surgery for Cushing’s Disease
Treatment depends on the severity of clinical signs, the pet’s quality of life and the owner’s resources. Cushing’s disease doesn’t have to be treated right away, but owners should be prepared for long-term clinical and therapeutic monitoring if treatment is pursued.
Vets Deal with Cushing’s in Three Ways:
- Minimize or stop the use of steroids, if the disease is iatrogenic. The body will eventually excrete the drugs and right itself. Unfortunately, a condition that required steroids in the first place (such as inflammatory bowel disease) may return. Then the vet and owner work together to balance care by regulating steroid use or finding an alternative, if possible.
- Surgery. The only way to cure Cushing’s is to remove a tumor from the adrenal gland before it spreads. Unfortunately, the pituitary gland is too small to make surgery practical. Because most pituitary tumors are benign, oncologic treatment is not necessary.
- Medication. Trilostane, the drug of choice, inhibits an enzyme responsible for forming glucocorticoids (particularly cortisol). A doctor may need several weeks to find an appropriate dose. Side effects can include gastrointestinal upset and, on rare occasions, permanent cortisol deficiency. The latter can make pets quite ill, so regular adrenal function tests are crucial. An older medication called Mitotane selectively destroys parts of the adrenal glands that make cortisol, so it is thought by some to be less safe than Trilostane, resulting in the decline of its use.
The prognosis varies but is generally considered to be good. Dogs with pituitary-dependent HAC rarely experience a life-threatening complication associated with treatment. Dogs with adrenal-dependent HAC have a median survival time of two to four years, though they often get this illness later in life. So, Cushing’s disease, diagnosed early in its progress, need not mean a shorter lifespan for your pooch.
CARE operates as the animal version of a medical center for humans, providing all forms of treatment for pets through emergency care 24 hours a day and 365 days a year. It also offers board-certified specialty care, once you get a referral from your primary veterinarian. Take a visual tour of the practice atcarecharlotte.com/tour.
