Addison’s and Cushing’s Disease in Cats
Adrenal gland disorders, including Addison’s disease and Cushing’s disease in cats, are often missed and underdiagnosed. We still don’t know a lot about these conditions, but if your cat is chronically or intermittently ill or is having unexplained symptoms, an undiagnosed adrenal disorder could be the culprit.
Addison’s Disease in Cats
Feline hypoadrenocorticism is commonly referred to as Addison’s disease in cats.
In Addison’s disease, something causes the adrenal glands to stop making important hormones, including cortisol and mineralocorticoids.
Addison’s disease is usually seen in middle-aged cats of both sexes. In dogs, Addison’s disease is known to be an autoimmune disorder, but we do not know yet what causes it in cats.
The problem with Addison’s disease is that it is sneaky and masquerades as other issues. It can camouflage itself behind nonspecific signs, like lethargy, dehydration, weight loss or vomiting.
Cats that have Addison’s disease can be misdiagnosed with kidney disease or inflammatory bowel disease because the signs are so similar.
Cats suffering from Addison’s disease can act sick intermittently, or they can have what’s known as a full-blown Addisonian crisis, which manifests as extreme shock, low heart rate and dehydration.
An Addisonian crisis is a medical emergency, and your cat will need to see a veterinarian immediately.
The most typical story is that your cat acts sick and dehydrated, goes to the vet, gets fluids and steroids, feels better and then gets sick again at some point. If this happens to your cat, then your veterinarian might start to suspect Addison’s disease and test for it.
Addison’s disease in cats is usually diagnosed with a simple blood test, but diagnosis is often confirmed by finding abnormally small adrenal glands during an abdominal ultrasound.
Treatment for feline Addison’s disease in cats depends on the type a cat has—some types of Addison’s disease require monthly injections of mineralocorticoids and daily oral administration of steroids, while other types only require oral steroids.
Your veterinarian will be able to sort out your cat’s needs and prescribe the appropriate prescription pet medications.
Cushing’s Disease in Cats
While feline hypoadrenocorticism is the result of an underactive adrenal gland, feline hyperadrenocorticism, or Cushing’s disease in cats, is the exact opposite. It is caused by excessive cortisol secretion from the adrenal gland.
Cushing’s disease in cats is caused by either a tumor in the pituitary gland or a tumor in an adrenal gland. Cats with Cushing’s disease tend to be older, but it can be seen in younger cats as well. There is no sex predilection.
Cushing’s disease is also tricky to diagnose in cats because a lot of the signs of Cushing’s disease—including increased thirst, increased urination, muscular wasting, enlarged liver and increased appetite—are the same signs seen in cats with diabetes.
One classic sign of Cushing’s disease in cats is thin, shiny, fragile skin and hair loss. Cat’s with Cushing’s disease often have additional problems with recurrent urinary tract infections, and they often have diabetes as well.
Diabetic cats that have become difficult to regulate with cat insulin should be tested for Cushing’s disease.
Cushing’s disease is diagnosed using blood tests. Your veterinarian may also order a urine test and abdominal ultrasound.
Treatment for Cushing’s disease in cats is either a surgical procedure or management with lifelong medication.
Cats that have an adrenal tumor can be cured with surgery, while cats with a pituitary tumor require medication to reduce the amount of cortisol secreted by the adrenal glands.
Feline Hyperaldosteronism
One of the sneakiest and most underdiagnosed adrenal conditions in cats is feline hyperaldosteronism. It’s an adrenal disorder in cats that’s widely underreported and undertested for because it is often confused for kidney disease.
Hyperaldosteronism is usually caused by a tumor in the adrenal gland that causes oversecretion of a hormone called aldosterone, which regulates sodium in the body.
There is a very rare version of hyperaldosteronism that is associated with rapidly progressing kidney disease, and this type of case requires management by an internal medicine specialist.
Signs associated with hyperaldosteronism include muscle weakness, lethargy, high blood pressure and loss of appetite. Cats may go blind due to retinal detachment caused by high blood pressure.
Hyperaldosteronism is tricky to diagnose—it requires a special test that is (currently) only run through Michigan State University. Dr. David Bruyette, DVM, DACVIM, medical director at West Los Angeles Animal Hospital and CEO of Veterinary Diagnostic Investigation and Consultation recommends screening all cats that have chronic kidney disease for hyperaldosteronism with the screening test that is available through Michigan State.
If that test comes back positive, then an abdominal ultrasound or CT scan is ordered to find the tumor. Treatment is surgical removal of the tumor, followed by appropriate medication.
If you suspect hyperaldosteronism in your cat, talk to your veterinarian about having your cat tested.
By: Dr. Sarah Wooten
Featured Image: iStock.com/knape
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