Kidney disease in your cat

Kidney failure is a common health problem in middle-aged and elderly cats. A gradual reduction in the ability of the kidneys to do their job is an inevitable part of the ageing process and occurs at varying rates in different animals. The damage is irreversible and will eventually be fatal. Your cat may still have many months of good quality life after diagnosis of kidney disease if receives effective treatment and you co-operate with your vet.

What causes kidney damage?

Damage to the cells which filter natural poisons (the normal waste produced by the body's internal processes) out of the blood for removal in the cat's urine is a normal ageing process. In time, so much kidney tissue is affected that these waste products can no longer be eliminated and build up inside the blood stream. This condition - which vets call chronic renal failure - is very common in cats over seven years old. Inherited defects (particularly in long-haired breeds), bacterial infections, viral diseases like Feline Leukaemia or Feline Infectious Peritonitis, poisoning and the growth of cancers can make the damage worse. Sudden or acute kidney failure can also occur as a result of poisoning, bacterial and viral infections, blockage of the tubes leading from the kidneys to the bladder or heart disease. These cases need emergency care and even if successfully treated by your vet, your cat may still suffer long term kidney damage.

What happens to a cat with kidney disease?

The kidneys have a lot of spare capacity for filtering blood, so symptoms only appear when about three-quarters of the kidney cells have stopped working. One of the first indications of disease is the loss of ability to produce concentrated (dark) urine. So to get rid of the same quantity of waste material your cat has to produce larger quantities of more diluted urine. Your cat will be thirstier than usual and have to pass urine more often. As the disease gets worse other symptoms may appear. Your cat may seem depressed and lose interest in food, vomit regularly, lose weight and its coat becomes dull. You may also notice bad breath and ulcers in its mouth. In the very final stages of the disease your cat may go into a coma.

How can I be sure that my cat has kidney disease?

Many of these symptoms also occur in other diseases such as diabetes. Your vet will want to test samples of blood or urine or perform X-rays or ultrasound examination of your cat to show that the kidneys are not working properly.

How is kidney disease treated?

Although damaged kidneys can not be repaired there is much that can be done to make your cat feel better. Many cats that are producing abnormally large amounts of urine become severely dehydrated. Your vet will want to give extra fluids to counter this and give medication to treat the secondary effects of the disease such as mouth and stomach ulcers. Damaged kidneys may be unable to get rid of waste products from the body and this may cause kidney or bladder stones. Anaemia is a common problem in cats with advanced diseaseand in some cats this may be treated.

What can I do to help?

The most important thing in helping your cat is to reduce the work load on the remaining healthy kidney tissue. This can be done by altering your cat's diet. There are special diets available from your vet which reduce the waste products in the blood. They also have extra amounts of some vitamins and minerals. Avoid giving your cat leftovers or treats which may interfere with the new diet. Affected cats often feel sick and lose interest in their food. It may help if you warm up the food to stimulate your cat's sense of smell or hand feed it while it is getting used to the new food. Feed it 'little and often' and throw away uneaten food. Always make sure your cat has plenty of fresh, clean water at all times, allowing your cat to go thirsty will make the problem rapidly worse.

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How long will my cat live?

If the damage to the kidneys is related to ageing your cat may live for several years after diagnosis. As with other diseases, if you can keep your cat comfortable there is a good chance that it will survive for many months. Your cat will need regular check ups by your vet and possibly changes to its medication. By weighing your cat often, watching its behaviour and checking how much food and water it consumes, you will be able to provide your vet with valuable information which help to control the disease.

Related Factsheets:
Samples - how they help your vet
X-rays and ultrasound
The older cat

If you want any other information on health issues concerning your cat please contact your veterinary surgeon who will be happy to advise you.