Diagnosis and management of chronic renal failure in the cat

Diagnosing and treating kidney failure in cats

source: Penney Barber
In Practice vol 25 no 6, June 2003
starts p306, 6 pages long

Kidney failure is common in cats, especially as they get older. Chronic renal failure (CRF) is three times more likely in aged cats than in aged dogs. Measurement of the cat's glomerular filtration rate is a more sensitive test for kidney dysfunction than assessing creatinine and urea plasma concentrations. A persistent low specific gravity for urine also supports a CRF diagnosis. Cats also need to be monitored after a diagnosis, and their treatment tailored according to findings.

The aim of treatment is to keep the cat's condition stable, since CRF is not seen as reversible. Cats may suffer from anorexia and dehydration, and need to be rehydrated , with electrolyte abnormalities corrected. Specific treatment may be needed for some renal diseases, such as those linked to bacterial infection of the upper urinary tract.
Commercial diets designed for cats with kidney problems can help their survival rates. These diets tend to have lower phosphorous, sodium and protein levels, and higher B vitamins, and potassium levels, as well as greater caloric density than average diets. It is easier to change a cat's diet in the early stages of the disease, since cats may lose their appetites as they become sicker, and low protein diets are less palatable for cats.

Malnutrition can cause serious problems for cats with kidney failure. Angiotensisn converting enzyme (ACE) inhibitors may help cats with CRF, but can have side effects, so the cats need to be monitored.

CRF can cause complications, such as high plasma parathyroid hormone levels, which can lead to bones being demineralised, and soft tissue calcification. This condition is tackled using phosphate restriction. Cats may also suffer from systemic hypertension, anaemia, potassium deficiencies, and infections of the urinary tract. The article examines diagnosis and treatment of CRF in cats in further detail.