The kidneys of a cat can become diseased in a number of different ways. Cats can be born with congenital kidney disorders or the kidneys can become damaged due to injuries, infections, kidney stones, tumors, and toxins (such as antifreeze). While all of these conditions are life threatening, they are, luckily, all fairly uncommon. The kidney condition of cats, which is very common, is a progressive deterioration of the kidneys with no apparent underlying cause that progresses with age. We refer to this as Chronic Renal Failure (CRF). This condition is the most common cause of death in aged cats.
When deterioration of the kidneys occurs, they are not able to function normally. The kidneys have several important functions. They help clear toxic waste products from the body, keep several blood chemicals at normal levels, and control fluid balance to maintain normal hydration. They also produce a hormone necessary for the production of red blood cells and are involved in the regulation of calcium and vitamin D. In the very early stages of renal failure, the body is able to compensate and symptoms may not be evident. As the disease progresses and imbalances become more marked, symptoms such as increased thirst and urination, dehydration, loss of appetite, lethargy, weakness, and vomiting may occur. Your veterinarian will be able to assess the state of your cat’s kidney function using blood and urine tests. In some cases, veterinarians may also use x-rays, blood pressure measurements, ultrasound and even kidney biopsies to gain more information about kidney function.
Chronic renal failure has been considered an incurable disorder, however in the last few years kidney transplantation has become a reality in feline medicine. There are only a handful of veterinary centers in the country doing kidney transplants, the procedure is very expensive and not all cats with kidney disease are candidates for transplantation. For those reasons, most cats with CRF will not get transplants and we must regard the disease as a progressive one that we cannot cure but can manage for months to years with proper veterinary care.
One type of therapy your veterinarian may recommend is a change in diet. Several diets are formulated specifically for cats with kidney disease. They differ from other cat foods in that they have a lower protein level and modifications in the levels of several other chemicals such as potassium, phosphorus, and sodium. Your veterinarian may feel this is an important part of your cat’s therapy. An important part of the treatment for cats with more advanced disease is fluid therapy. Fluids infused through an intravenous catheter or infused subcutaneously (under the skin) help flush out waste products through the kidneys as well as restore hydration and correct certain chemical imbalances. This type of treatment does not always require hospitalization. Many cat owners learn to give their cat subcutaneous fluids at home.
Depending on what specific complications your particular cat has, your veterinarian is likely to prescribe one or more of several medications. These include blood pressure medication, potassium supplements, vitamins, iron, phosphate binders, hormones to correct anemia, and drugs to treat gastrointestinal upsets. Once chronic renal failure is diagnosed your veterinarian will want to follow your cat’s condition with regular check-ups and testing and will tailor a treatment plan specifically for you and your cat. It is hard to predict for each cat how quickly this disease will progress, but with early diagnosis and proper care, some cats can enjoy a good quality of life for several years.