The kidneys are responsible for eliminating waste products from the body and maintaining fluid balance. Kidney disease is a very significant cause of illness in cats.

Signs Your Cat May Have Kidney Disease

The first warning is an increased thirst due to an inability to concentrate the urine as efficiently, but as many cats do not drink from a bowl, this can be difficult to identify. An observant owner may notice a change in the cat’s pattern of behavior, and a cat that perhaps never used to drink much at all, may be spotted regularly drinking from a pond, a tap or other water source.

As the disease process progresses, waste products from the breakdown of protein within the body start to build up, and, in turn, cause further damage to the remaining kidney tissue. Signs of kidney disease include: -

  • Excessive thirst
  • Lack of appetite
  • Weight loss
  • Poor condition
  • Bad Breath
  • Ulcers in the mouth
  • Softening of the bones
  • Anaemia

Eventually, the cat will refuse to eat altogether. It may start to have convulsions, and will inevitably die.

Once the disease develops, a blood test will show an increase of urea in the blood, as well as an increase in an enzyme called creatinine. An increasing number of veterinary practices are using a combination of blood and urine tests during routine health screens of elderly pets to pick up impending problems at an early stage.


There are many possible causes of kidney disease, such as bacterial infections, congenital abnormalities, the effects of toxins, and tumors. However, by far the commonest cause is chronic interstitial nephritis – a gradual replacement of the normal kidney tissue with scar tissue that develops with age.

The causes are not well understood, nor why some cats develop it much sooner than others. It is possible for the a cat to have up to two-thirds of its kidney filtration cells damage without showing any signs of illness at all, so by the time that the condition is clinically recognizable, the underlying disease process is already well advanced.


A lot can be done to slow down the progression of the disease and give the cat a longer lease of life, but early diagnosis is essential. It an underlying cause such as infection can be identified then, of course, it bust be treated. However, most frequently we can only give palliative treatment to enable the cat to cope as well as possible with the kidney function that it has remaining. Cats are often dehydrated by the time the problem is diagnosed, so an intravenous drip may be needed to correct this. Drugs may also be used, such as vitamins and anabolic steroids to stimulate the appetite, and anti-emetics to control vomiting.

The most important aspect of treatment kidney disease involves a change in diet to a food specially designed to reduce the workload of the kidneys. Cats cannot manage on very low protein diets, but a diet with a moderately restricted level of high – quality, easily digested protein will reduce the amount of protein waste products that build up in the body. Even more important is a restriction on the amount of phosphorus in the diet, as this accumulates in the body of cats with kidney problems and causes further damage to the kidneys.

The levels of B vitamins need to be boosted because they tend to be lost from the body when the kidneys are not working properly. While it is theoretically possible to achieve this with a homemade diet, it is extremely difficult to get the balance just right, and a range of pre-prepared diets are available from veterinary surgeries to help control the problem.