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Kidney Disease

Kidney failure is relatively common in cats, especially when they start to get older. So even though your cat has been recently diagnosed with kidney failure - don't despair as modern treatments are now available which improve both quality of life and life expectancy.

Cats like us have 2 kidneys which work as filters in the body removing waste products from the blood stream.

These waste products are then excreted fom the body via the urine. The kidneys also have the function of regulating water balance and produce various hormones.

Causes of chronic renal failure

• Polycystic kidney disease (an inherited condition seen mainly in Persian and Exotic cats where normal kidney tissue is gradually replaced by multiple fluid filled cysts that develop within the kidneys).

•  Kidney tumours – for example lymphoma or tumours caused by Feline Leukaemia Virus can affect the kidneys and cause renal failure. 

•  Infections – bacterial infection of the kidneys or pyelonephritis may occur as an extension of bladder infections and can lead to sufficient damage of the kidneys to cause renal failure.

•  Other causes - eg damage to the kidneys by toxins, defects in the development of the kidneys at birth, continuous inflammation such as glomerulonephritis.

As the kidneys begin to fail, they become unable to create urine in the normal way. It becomes less concentrated which means your cat may become thirsty and urinate more frequently.

When approximately 2/3 of the kidney tissue has been damaged, toxic waste products begin to build up in the bloodstream which may cause loss of appetite, weakness, vomiting or mouth ulcers.

This is why your cat stops eating as it feels nauseous. You may also notice a stark, matted coat as they stop grooming themselves regularly if mouth ulcers have developed.

High blood pressure may also occur in cats with kidney failure which can result in sudden blindness.

The toxic waste build up is excreted through the saliva so you may notice a smelly breath called ketosis. Muscle deterioration occurs which appears to you as if your cat has suddenly lost a lot of weight.

Kidney failure may come about prematurely in your cat when there is a spell of very hot weather. They do not drink enough when the weather changes and may dehydrate which puts a strain on already damaged kidneys.

Dietary control of kidney failure

  • Cats with chronic renal failure are more likely to become dehydrated (due to the reduced ability of the kidneys to conserve water by concentrating urine). Maintaining a good fluid intake is very important, and as cats generally gain much of their water from their food, whenever possible, cats with chronic renal failure should be fed tinned or sachet foods rather than dry foods.
  • An ideal diet for a cat with renal failure should have a low protein content – many of the toxic products that accumulate in the blood in renal failure are a result of protein breakdown to ammonia, and feeding a low protein diet will therefore help to minimise this. Too little protein in the diet can lead to excessive weight loss that would be detrimental to general health. For this reason it is best to use specially designed commercial diets as prescribed by your vet.

Other Treatments

  • Treat hypertension or high blood pressure with tablets to prevent retinal detachment and blindness.
  • Some cats with renal failure develop low blood potassium levels, and this itself can worsen the renal failure. Where this is identified potassium supplementation is of benefit.
  • Iron supplementation to treat the anaemia
  • Nausea and vomiting are more common in advanced renal failure and can significantly affect the quality of life and the appetite of the cat. Where this is a problem, various drugs can be used to control these signs.
  • ACE-inhibitors are a class of drugs that act predominantly as vasodilators (dilate blood vessels). They appear to have beneficial effects on renal function and reduce protein loss through the kidneys (which can be elevated and can be harmful in renal failure).

With modern advances, your cat should still lead a good quality of life.

Cystitis - see under Urinary Tract Disease