Cushing's disease in cats, or hyperadrenocorticism, occurs when the adrenal glands produce too much cortisol. Cortisol is a hormone essential to many bodily processes, but when your cat's body produces too much of it, it can cause serious health problems.
Causes of Cushing's Disease in Cats
Most cases of feline Cushing's disease are what's known as pituitary dependent hyperadrenocorticism, which occurs due to a pituitary in the cat's brain. While not usually cancerous, this type of tumor can secrete adrenocorticotropic hormone, or ACTH. ACTH overstimulates your cat's adrenal gland, causing it to produce too much cortisol.
About 20 percent of feline Cushing's disease cases occur as a result of an adrenal cortex tumor, which can grow on the outside of the adrenal gland. This is known as adrenal dependent hyperadrenocorticism.
Cushing's disease is relatively rare in cats. Most cats that get it are female, and most are older than 10 years of age. There is no apparent connection between this disease and breed type.
Symptoms of Cushing's Disease in Cats
The most common symptoms of Cushing's disease in cats are increased appetite, increased thirst and increased urination. Cats with Cushing's disease may lose hair in a symmetrical pattern from both sides of their bodies. Their skin may become fragile and easily broken or bruised. Remaining fur may appear poorly groomed and lackluster.
Cats with Cushing's disease may experience wasting of the muscles and may begin to look like they have a pot belly. They may gain or lose weight, suffer from recurrent infections and appear lethargic.
Diagnosing Cushing's Disease in Cats
Your vet will need a thorough physical exam and a complete medical history in order to diagnose Cushing's disease in your cat. Your vet may also need to perform a wide range of diagnostic tests. He or she may perform complete blood counts, urinalysis and biochemical profiles. X-rays, ultrasounds, MRIs and CT scans may be performed, and, of course, your vet will need to test your cat's blood levels of ACTH.
Treating Feline Cushing's Disease
While there are medications available to treat this disorder in cats, they are not terribly effective. Your vet will probably recommend surgery. If your cat is suffering from pituitary dependent Cushing's disease, the vet may need to remove both of the adrenal glands. If your cat has adrenal dependent Cushing's disease, he may need one or both adrenal glands removed.
Once your cat has had surgery to remove his adrenal glands, he will need continued lifelong medical care. If your cat also suffers from diabetes, his insulin dosages may need to be adjusted; you'll have to watch him carefully in the weeks after surgery for symptoms that his blood sugar is out of control. Your vet will monitor the cat's blood sugar and reaction to insulin during the post-op recovery period, and your cat will need frequent vet visits to make sure his blood sugar remains controlled.