Cats’ kidney problems

Kidney disease, or chronic renal failure, is one of the most common illnesses in older cats, with up to a third of all cats over the age of 15 being affected. That’s why it’s something that all Vets are on the look out for at annual health checks. For those cats crossing in to their “teenage years” it’s now more usual to have twice yearly health checks just to try and pick up the very early signs of kidney problems.

The difficulty we have with chronic renal failure is that it is an irreversible condition since a damaged kidney cannot regenerate. Fortunately though the kidney has considerable reserves and in the early stages the damage to the kidney may pass unnoticed. That’s why, during health checks in older cats, one of the routine checks made is on a urine sample – not always the easiest thing for an owner to get from a reluctant cat! For those that do use a litter tray indoors, there is now a non-absorbable litter that we Vets supply prior to these senior checks to try and get a sample. But of course cats aren’t always co-operative. Where this occurs we also have the facility to take a very small urine sample, via a syringe and needle, from the bladder itself. It’s a very simple and safe procedure and is remarkably well tolerated by almost all cats. Of course this assumes that your cat has a full bladder. As I said, not all cats cooperate!

The reason why a urine sample is so useful is because testing it gives us a very early warning of changes happening in the kidney. And of course, if we can detect things early there’s a much higher chance of slowing down the progression of the disease. A blood sample is the next best thing, but when signs of renal damage appear in the blood, then about 75% of the kidney tubules (nephrons) are non-functional. Even at this stage help is available, but it’s pretty obvious that if we can get in earlier then a lot more can be done to help.

What signs might I notice in my cat?

An increase in urinating and an increase in thirst are quoted as the most common early signs that may be seen in cats with a developing chronic renal failure. Of course, most cats that go outside tend to wee outside, so that part may be difficult to detect. And in a multi cat household it’s not always easy to tell if one individual cat is drinking more than another. Other signs that may be noticed are a loss of appetite, sometimes cats are sick and there may be weight loss along with a drop in body condition. At the annual (and for older cats, biannual) health checks weight recording is an very important part of the examination. Subtle small losses in weight over several visits may be the only sign that something is remiss. Fortunately, with a cat’s weight being recorded at every visit, a library picture has been built up for your individual cat so that weight change outside of the normal boundaries will alert us to a potential problem. Eye checks at this time are also important as they give a hint about another aspect of kidney changes in about a fifth of such cats that involve an increase in blood pressure.

What can be done to help?

Quite a lot. Because one of the greatest problems we have with cats suffering with kidney disease is a loss of appetite it’s really essential to get them eating. However, highly-flavoured, highly-salted diets can be a real issue for a cat with a damaged kidney. One of the most important parts of our “treatments” to help cats with kidney disease is the introduction of a prescription diet restricted in phosphorus and sodium as well as being moderately restricted in protein. For those cats that transfer successfully on to a prescription diet they have a life expectancy three times longer than those that refuse the food. Anecdotally, those cat that are “finicky” with their food in their early years, or get lots of different types of diets in their life, prove to be the most difficult to transfer over. It is much more important that a cat eats something though, even if it’s not the ideal diet. Diets can be modified by adding things to them to ‘recreate’ a kidney diet.

Kidney-damaged cats will also suffer with urine infections as a result of producing a weakly concentrated urine. Routine checks are made to check for any infections. They also suffer much more with mouth infections.

It certainly isn’t a hopeless situation for cats with kidney disease Early diagnosis is the key to helping though. With regular health checks this can usually be achieved long before the situation has started to spiral out of control.

© copywrite Dai Gittins MRCVS.