The Chronic Kidney Disease

Early intervention is critical, but there’s help and hope

If you’ve been lucky enough to have a cat or three make it into later life, you’ve probably battled chronic kidney disease (CKD). It’s one of the most common ailments of senior cats, and about a third of all cats develop it. Worse yet, it’s an insidious disease that creeps up on older cats—and their owners.

The kidneys filter toxins and wastes out of the blood and recover important nutrients and electrolytes. Two-thirds or more of the normal kidney tissue must be damaged before CKD can be detected through blood tests.

The first CKD signs you’ll probably notice are increased thirst and urination, weight loss, a lack of appetite, and lethargy. Some owners note bad breath or drooling, which can be associated with oral ulcers caused by the buildup of toxins in the blood. Cats who aren’t feeling well may not groom themselves, so your cat may develop mats and lose that sleek coat. As waste products further build in the bloodstream, your cat may suffer from nausea and vomit.

Causes of CKD vary widely—inflammation, kidney stones or a blockage, an infection, immune system disorders, heredity—but usually CKD is considered idiopathic, meaning there is no known cause.

Making a Diagnosis

Your veterinarian will do a physical examination, which may include a blood-pressure test (hypertension is often seen with CKD). Urine will be evaluated to see if your cat can concentrate/dilute her urine, to check for protein loss, and to rule out bacterial infection. In later stages of CKD, blood tests may show anemia, an increase in blood urea nitrogen (BUN), and an increase in creatinine.

Your veterinarian can classify what stage of kidney failure your cat is experiencing by evaluating these blood tests. A newer lab test that measures the concentration of symmetric dimethyl arginine (SDMA), a waste product of protein metabolism, is being used in some clinics to detect CKD at earlier stages of the disease. An earlier diagnosis means treatment can begin sooner, which is better for your cat’s prognosis.

Multi-Step Treatment

Your veterinarian may recommend modifying your cat’s diet. Dietary modification is the only intervention that has been shown to improve outcomes in cats with CKD (see sidebar).

Medical therapy includes:

  • Controlling hypertension, usually with oral medication
  • Treating urinary protein loss, often with angiotensin converting enzyme (ACE) inhibitors
  • Addressing anemia, which may be treated by replacement therapy with erythropoietin, which stimulates red blood cell production
  •  Stimulating appetite, using various drugs, as needed

While humans with kidney failure are often treated with hemodialysis, or simply “dialysis,” this modality is not practical for most cats. It is primarily used for emergencies in which the kidneys are acutely affected, such as in a poisoning. In these situations, the cat is expected to recover relatively normal kidney function.

While some specialty clinics and university facilities offer feline kidney transplants, it’s not easily done. The donor cat must be adopted and cared for by the family of the cat receiving the transplant, and the cat receiving the kidney will need anti-rejection medications for the rest of her life.

Stem cell therapy, while in its infancy for feline CKD, shows promise.

Many cats respond well to treatments that slow the progression of CKD. Although CKD cannot be cured, cats can gain years of relatively normal health and activity. It probably won’t surprise you, however, to learn that some cats limit their own treatment by failing to cooperate with many therapies.

What You Can Do

Dietary modification can make a big difference

Adjusting your cat’s diet is a critical part of managing CKD.  Your veterinarian may recommend modifying your cat’s diet to limit her phosphorus, sodium, and protein intake. He or she also may consider phosphate binders, potassium supplements, antioxidants, and/or water-soluble vitamins, which are lost with kidney failure.

You’ll find a variety of commercial and prescription therapeutic diets for cats with kidney problems. Discuss your options with your veterinarian and try various ones to find one your cat likes, then do a gradual shift (over five to seven days) from her regular food. She may need anti-nausea medications until she is stabilized.

Many people find that diets with a lower protein content—even in a high-quality protein diet—are not palatable to their cats. For this reason, many owners have opted to make food at home or feed a raw diet.

If you choose this option, be sure you consult a veterinary nutritionist, because creating a balanced diet for a cat with kidney failure is not simple. You can find a board-certified veterinary nutritionist at In addition, the Cornell University Veterinary Nutrition Service offers fee-based nutrition consultations. You can call 607-253-3060 or visit

Learn to Do Sub-Q Therapy

Although increased thirst and urination are signs of kidney failure, prompting cats with CKD to drink is important.  That may mean investing in a fountain if she prefers that to a bowl or giving subcutaneous (sub-q) fluids at home on a regular basis, especially as the kidney failure worsens. Giving sub-q fluids is not difficult to do, and most cats handle this well. Your veterinary team can provide you with the necessary training and support.