Chronic Renal Failure (CRF) is the term used to describe the gradual deterioration of kidney function over time. While there are many possible initiating causes, including toxins, cardiovascular damage and cancer, it is usually very difficult to determine the exact cause. Unfortunately kidney damage is irreversible and animals in kidney failure cannot be cured. However, the symptoms and complications can be managed to provide as best a quality of life as possible.

Clinical Signs of Kidney Disease
There are many symptoms of renal disease resulting from impairment of normal kidney function. Animals with CRF may show a gradual deterioration in their condition or have episodes of sudden illness (acute renal failure – ARF).

The most common clinical signs of kidney disease are:

  • Increased thirst and urination – the kidneys are responsible for concentrating urine to help maintain the body’s hydration. Damaged kidneys lose this ability and as a result affected cats will produce large quantities of urine. This will cause them to drink more. However, cats are usually unable to fully balance their water intake and urine output and become dehydrated despite the increased water intake. You can test your cat’s hydration status by picking up and dropping a tent of skin on the back of their neck. Well-hydrated skin will quickly fall back to normal (e.g. as occurs when testing the skin on the back of your hand), whereas dehydrated skin will take longer.
  • Oral ulcers – when the kidneys are not functioning normally, levels of nitrogen compounds build up in the blood. These can result in mouth ulcers which can manifest as pain when eating, bad breath, and increased salivation.
  • Vomiting – the toxins that build-up in the blood can also cause nausea. Cats will often vomit (sometimes this will contain blood) even when the stomach is empty.
  • Anorexia and weight loss – cats affected by renal disease are often off their food due to nausea or just a general sense of illness. Their bodies may also enter a physiological state where muscle is broken down faster. This can result in dramatic weight loss.
  • Anaemia – red blood cell production and life-span are often affected by kidney disease. The resulting anaemia can result in paleness of the gums, breathlessness and weakness.

Management of Chronic Renal Failure
While the following will not cure kidney disease, they can increase your cat’s ability to tolerate the disease, slow it’s progression, and improve your cat’s general quality of life.

  • Rehydrate – Maintaining hydration can help flush toxins from the body and generally improve well-being (think how you feel after being in the sun too long or after a night’s drinking!). Providing a wet food diet, unlimited access to water and administering fluids under the skin when required, can help your cat feel much better.
  • Treat hypertension – High blood pressure can cause further damage to the kidneys, and potentially other organs such as the eye. Blood pressure can be lowered through the use of some heart medications.
  • Dietary – Restricting protein intake helps to reduce the level of nitrogen compounds in the blood, reducing the degree of mouth ulcers, nausea, and weakness experienced by your cat. It is also useful to decrease the intake of phosphate (to help slow the progression of disease and reduce the risk of secondary hyperparathyroidism) and fed a diet that provides alkalinisation (to counter a build-up of acidic compounds in the body). Lowering the fat content of the diet will help to counter increased cholesterol levels. Special kidney diets have been formulated to provide these features e.g. Hills k/d, Eukanuba Multi-Stage Renal diets. If your cat won’t eat these, try to find a diet containing these features, or feed a wet food.
  • Treating complications – Dilute urine following a decrease in kidney functioning ability can predispose to the development of urinary tract infections (UTIs). These result in an increased frequency of urination (often with little urine produced), blood in the urine and general discomfort. Urine testing can detect these, and antibiotic treatment may be required.
  • Avoid Stress – Stress can result in increased levels of steroid release in the body. These steroids can increase the level of muscle tissue breakdown.

Cats with CRF may cope well despite their disease. Occasionally they may have episodes of acute deterioration – these need to be managed aggressively with intravenous fluids and other therapy.