Kidney Problems in Cats

The kidneys are vital organs that perform a whole host of important functions in the body. Kidneys primarily filter waste materials from the blood (excreting them in urine) and are also involved in the regulation of body minerals and blood pressure, as well as producing vital hormones. As such, they are constantly in demand by the rest of the body, and any issues with them can cause a number of serious problems. Kidney failure is very common especially in older cats who usually suffer from the chronic form of the disease.

There are two kinds of kinds of kidney failure:

Acute kidney failure

This is the sudden inability of the kidneys to function properly. Acute kidney failure in cats can be caused by infection or ingestion of toxins. Kidney damage of this kind can sometimes be reversible, but not in all cases.

Chronic kidney failure

Chronic feline kidney failure occurs over a long expanse of time, from months to years. Causes can range from infections to tumours but usually the cause is unknown. By the time chronic kidney failure is diagnosed it is irreversible but fortunately treatments do exist which reduce the progression of the disease and help ameliorate symptoms.

In the early stages of disease healthy areas of the kidney compensate for damaged areas by taking on their workload. However, as the disease progresses, functioning areas are lost and the remaining healthy areas cannot make up for overall loss. Once this occurs your cat will show signs of kidney failure. Chronic kidney failure is a progressive disorder and many cats develop some degree of failure as they get older due to the gradual deterioration of the parts of the kidney that do the work. The condition is usually managed using fluids, special diets and medicines to help slow disease progression and help your cat feel better despite her condition.

Signs to look out for

Your cat may become unable to concentrate its urine correctly, so it will produce large amounts of diluted urine. This means your cat will urinate more, which in turn will make its drink more to replace the fluids being lost. It’s a dangerous cycle so any deviation in either drinking or urination in older cats should be looked out for. Never withhold water from cats to attempt to reduce their urination as this could cause dangerous dehydration in cats with kidney disease.

Your cat could also be suffering from a poor appetite, and seem tired and generally lethargic. This is because the toxins that would normally be excreted in the urine are now building up in the body. This can also make your cat feel nauseous, resulting in vomiting or retching and may also result in bad breath.

Diagnosis by your vet

Your vet will want to test a urine sample, which will show if the urine is being concentrated, whether protein is being lost in the urine, and whether there are any other problems (such as underlying infections) to take into account.

Your vet will also take a blood test. Whilst testing specifically for kidney function, some vets will also use the opportunity to do a full blood screen to check the other organs and systems for a full health profile of your cat as sometimes the toxin build up can have a knock-on effect on other organs.

Treatment is usually handled by dietary control or medication, or both depending on the severity of disease.


Cats with kidney failure may develop conditions such as high blood pressure or anaemia.. Your vet may recommend specific medication to help control these problems


A tailored diet has been proven to reduce signs of kidney failure and slow disease progression and as such dietary modifications are the cornerstone in the management of chronic kidney disease in cats. Your vet may recommend a special diet known as a ‘veterinary prescribed’ diet to help your cat.

Diets should be changed very gradually to reduce the risk of tummy upsets and encourage your cat to eat the new formula. Do not give up the new diet just because your cat seems disinterested. Unless stated otherwise by your vet you should thoroughly blend in the new diet into your cat’s original diet. This involves increasing the new diet by very small amounts on a daily basis, whilst at the same time reducing the amount of the original diet.

The changeover process can take from two to six weeks to complete. Bear in mind that although time consuming, the new diet is extremely important to your cat’s health.

A few tips:

  • • Avoid giving treats - or use some of the special diet kibbles as treats instead.
  • • Offer small meals on a frequent basis, rather than one or two large meals.
  • • Wet food can be heated in the microwave until lukewarm (never hot) to release aroma and soften texture.
  • • Dry food can be soaked briefly in warm water to soften texture if your cat is used to canned food.