What is Feline Chronic Renal Failure?

CRF should not be confused with acute renal failure, which caused so many deaths in the 2007 tainted pet food recall tragedy.

Extremely common in older cats, CRF is a serious condition evidenced by gradual, irreversible deterioration of kidney function over a period of months or years. The kidney consists of tiny funnel-shaped tubes called nephrons, which filter and reabsorb the fluids that balance the body.

When an individual nephron is damaged by any cause, (aging, poison, infection, etc.) it stops functioning.

Fortunately the kidney can still function with as few as twenty-five percent of its original nephrons, as other nephrons can grow larger to "fill in the blanks."

Kidney failure occurs when the remaining functioning nephrons drop below 25%. Kidney failure creates several body disfunctions: Toxins, such as urea and creatinine which normally are secreted as waste, build up in the blood.

Other components in blood, such as phosporus or sodium may rise or fall abnormally. Urine may contain protein which is not handled well by failing kidneys.

How is CRF Diagnosed?

CRF is diagnosed by a blood panel, which measures levels of critical blood components such as blood urea nitrogen (BUN), creatinine, and a red blood cell count. Analysis of urine will test for protein, bacteria, and blood, as well as how well the kidneys are concentrating urine.

What are the Symptoms of CRF?

All but one (difficulty urinating) of the symptoms listed below can also be indicative of other disease, e.g., hyperthyroidism.

  In fact, hyperthyroidism may mask CRF, which points out the need for an accurate diagnosis.

• Weight loss
• Excessive thirst and urination
• Loss of appetite
• Vomiting
• Obvious difficulty in urinating
• Dull or ill-kept coat

How is CRF Treated?

• Subcutaneous Fluids (Sub-Q): Severely affected cats may have to be hospitalized for rehydration, however most people can learn to administer Sub-Q at home. Additional fluids may also be added to food.
• Diet: Your veterinarian may prescribe a low protein,low phosphorus diet, based on your cat's overall health. If at all possible, feed your cat raw or canned food for the added moisture.
• Medication: Depending on related problems, such as hypertension or anemia, your veterinarian may prescribe a number of different medications. Epogen shots may be given, or oral medication for cleaning the blood of toxins released by the kidneys.
• Appetite stimulants: If anorexia is a problem, your veterinarian may prescribe these, although cats often start eating again once they are sufficiently hydrated. Since CRF cats often have poor appetites, it is important to get your cat to eat something, if they shun their prescription foods. Human baby food meat (NO onions), tuna juice (albacore), juice from packets of premium cat foods or other similar enticements can be added to spice the taste of the prescribed food and to help stimulate the patient's appetite. You may even use "forced feeding" with high quality canned food mixed with water or other fluids, administered with a small syringe, if weight loss is severe. You do not want to add hepatic lipidosis (fatty liver disease) to your cat's health problems.
• Hemodialysis: Although the equipment is expensive and unlikely to be found in your local veterinary clinic, if you are fortunate to live near a large teaching college with the facilities, hemodialysis is a possible last resort treatment.
• Kidney transplant: This is probably not an option for an elderly cat, and is quite expensive.

Managing a CRF cat will produce a roller-coaster of emotions, as you find yourself overjoyed or in despair over the latest BUN and Creatinine numbers. Try to remember the old medical adage to "treat the cat, not the numbers. One of the best things you can do for your CRF cat is to try to relax, keep stress for both of you at a minimum, and enjoy your close relationship as you travel this road together.