Kidney Failure in Cats

Early Recognition of Kidney Disease Critical

Dr. Moira Drosdovech
Pawsitive Veterinary Care


My own cat eventually died of kidney failure at the age of 18 years old. He was 13 years old when I noticed him at the water dish more frequently than usual (the water dish was often the toilet!). He was still in excellent body condition and still had a great appetite. I did some blood work and found that one of the blood values used to determine kidney function was slightly high and his urine was quite pale or ‘unconcentrated’. This was the cat that I just knew was going to live until he was 25 years old and here he was with a terminal illness. Very disappointing news. Indeed, this same news is received frequently by cat owners whose cats are in the 7 years plus age group.

Chronic renal failure (CRF) is unfortunately very common in cats of all breeds and is one of the leading causes of death in older cats. Many factors may play a role in your cat’s onset of kidney failure, including age, genetics, environment (including diet) and disease. A current study by Dr. M. Lappin at Colorado State University indicates that cats vaccinated with the FVRCP (distemper) vaccine will develop autoantibodies against kidney tissue as the vaccine is grown using kidney cell culture. Dr. Lappin says that “Further research will be needed to define
the role of these autoantibodies in the development of chronic renal failure in cats.”

As the kidneys progressively fail, the blood levels of ‘poisons’, or waste products of metabolism normally excreted by the kidneys, build up. Once your cat reaches the age of 7 years or older, it is recommended that the cat be specifically checked for signs of CRF during each annual exam. Early detection is absolutely critical to the quality and length of life for a cat with CRF.

The early symptoms of CRF, as with my cat, are increased thirst and a litter box that is requiring more frequent cleanouts with larger clumps of urine. As CRF gets progressively worse, your cat may also lose its appetite, vomit, lose weight, lose hair coat quality, have very bad breath and perhaps develop ulcers in their mouth. It is important for you to know that by the time these symptoms are present, the animal will have already lost approximately 70% of its kidney function, so time is of the essence!

Too many times veterinarians see cats in the final stages of CRF, when it is too late for the vast majority. If you notice any changes in your cat’s thirst, weight or appetite, that would be the time to take them in. Treating CRF over a long period is not a costly endeavour and can be very rewarding. Initial tests normally include a blood panel and urinalysis. It is recommended that these tests be repeated at intervals of 6-12 months to monitor the disease.

A new urine test is currently being developed to detect the presence of microalbuminuria (small amounts of albumin) in feline urine. The presence of albumin in the urine is an indicator of kidney damage associated with renal failure and/or other underlying conditions causing albumin to leak into the urine. This new tool is the only test that will detect albumin leakage and will provide an early diagnosis of kidney damage apparently long before conventional blood tests show a problem.

Once you have a diagnosis of CRF in your cat, you probably want to know what to do. Diet plays a big role in treating CRF, but there is ongoing controversy as to what constitutes the best diet. While high protein diets do not cause kidney failure, they may aggravate it once it is present. However, more important than the total amount of protein is the quality of protein and the available calories in the diet from non-protein sources. Do your research before you choose a diet plan for your cat.

I started my cat on a low protein canned diet which he ate for a few months, then refused that, so I switched to a geriatric caned diet, then raw food, then back to some canned food in his last year as his appetite gradually waned.

I took him completely off of dry food right away as I felt his kidneys had enough trouble trying to conserve water without having to worry about the food being dehydrated as well! If I had it to do over again, I would choose a raw diet with high quality protein sources, and then add extra fat and an easily digested carbohydrate source to provide the necessary calories.

Depending on how advanced the disease is, regular administration of subcutaneous fluids to help the kidneys function better and flush out more waste products might be recommended, even if your cat is not dehydrated. Many cat owners do this fluid administration themselves at home, needle and all, to save money and stressful trips to the vet clinic.

Certain whole food supplements are very beneficial to kidney function and I use these regularly in my practice. With the help of the raw diet, I have seen some cats improve their blood work from one year to the next. Conventional treatment might include a drug known to help improve blood flow to the kidneys that is also used for treating heart failure in dogs.

Some herbs, such as alfafa, nettles and dandelion, also support the kidney. The only problem comes from figuring out how to get your cat to eat these herbs. Teas can be made of some and then given as a liquid. Some companies make their herbs in liquid forms that can be quite palatable. Homeopathic remedies may also be very useful to help moderate the course of your cat’s illness.

Although CRF is ultimately fatal, the course of the disease is not always rapid. I had 5 extra years with my cat after his diagnosis and only the last two weeks were what I would consider stressful. He didn’t live until he was 25, but I’ll bet my current cat will.