Overview of Chronic Renal Failure in Cats
Dog Breeds
Chronic renal failure (CRF) in cats is a progressive disease caused by long-term insult to the kidneys which, over time, damages their ability to concentrate urine and remove nitrogenous waste products from circulation.
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Definition of Chronic Renal Failure
Chronic renal failure (CRF) in cats is a progressive disease caused by long-term insult to the kidneys which, over time, damages their ability to concentrate urine and remove nitrogenous waste products from circulation. CRF is one of the most common causes of death in companion cats. Unfortunately, the symptoms of chronic renal failure usually are not apparent until the cat’s kidneys have already been severely and irreparably damaged. By the time CRF is diagnosed, roughly 70% of functional renal tissue already has been destroyed.
Causes of Feline Chronic Renal Failure
Why cats develop chronic renal failure is not well-understood. It may be that with advancing age, the kidneys simply wear out. Genetics appear to be a factor as well, with a predisposition for familial inheritance reported in certain breeds. Other contributing factors include:
- Exposure to poisons (nephrotoxins are substances that destroy kidney cells)
- Congenital kidney disorders (those existing at birth)
- Prior episodes of acute renal failure
- Chronic urinary tract obstruction (narrow urethra, chronic infection, kidney or bladder stones)
- Drugs (especially nonsteroidal anti-inflammatory drugs [NSAIDs] and certain nephrotoxic antibiotics)
- Polycystic kidney disease (a common congenital defect of the kidneys)
- Lymphoma (a specific type of cancer)
- Infectious diseases (especially feline leukemia virus and feline infectious peritonitis)
- Exposure to heavy metals (mercury, lead, thallium)
- Possibly diabetes mellitus
- Abdominal trauma (especially when the pelvis is fractured and the bladder is ruptured)
A number of other, kidney-specific diseases can contribute to chronic renal failure, such as glomerulonephritis, pyelonephritis, tubulonephrosis, amyloidosis and tubulointerstitial nephritis. A veterinarian is the best person to discuss these specific disorders with the owners of affected cats.
Unfortunately, the cause of chronic renal failure in cats usually is never determined. Regardless of the specific cause, CRF ultimately is the end result of serious insult to kidney cells over along period of time. Once approximately 70% of functional kidney tissue has been damaged, the affected kidney can no longer concentrate urine and remove waste products from the blood. As waste products build up in circulation, they cause a number of medical consequences. Chronic renal failure is progressive and irreversible.
Prevention of Chronic Renal Failure in Cats
Because veterinarians often cannot determine the cause of chronic renal failure, owners may struggle with the thought that maybe they could have done something to prevent their cat’s disease. They should not engage in that futile exercise. The majority of chronic renal failure cases cannot be prevented, and most of them are not particularly responsive to treatment. At this time, many feline CRF cases can be managed, but none can be cured. Companion cats – especially those over 7 years of age -- should receive an annual veterinary examination with blood and urine screening to monitor kidney function and the health of other vital organs. Dietary management can be helpful; a number of good commercial renal diets are available with a veterinary prescription. Of course, free access to fresh water is always important. Cats with known familial renal disease should not be part of a breeding program.
Special Notes
Cats with chronic renal failure can be asymptomatic for months to years. Early diagnosis of CRF and conscientious supportive care can delay progression of the disease and help maintain the cat’s quality of life.
Causes