Kidney Failure (Uremia) Treatment in Cats
Acute kidney failure can be reversed if the underlying cause can be corrected before it permanently damages the nephrons. If the insult is severe, hemodialysis (more commonly called dialysis) may be necessary to try to give the kidneys a chance to heal. Dialysis is most commonly used short term to treat acute renal failure or toxicities, or while a search is conducted for a transplant candidate. Dialysis is extremely expensive, can only be done at a few veterinary referral centers, and still requires extensive medical management of the cat in addition to the dialysis sessions.
Most cases of chronic kidney failure occur in cats who have sustained irreversible damage to the kidneys. However, these cats may still have many happy months or years of life ahead, with proper treatment. It is extremely important to be sure these cats take in enough water to compensate for their large urine output. A supply of fresh, clean water should be available at all times. Many cats will need supplemental fluids, given either intravenously at the veterinary hospital or subcutaneously at home.
The diet of a uremic cat should include protein of high quality, but lower in total amount, to minimize the amount of phosphorus and nitrogen that must be excreted by the kidneys. Special diets are available through your veterinarian. Canned foods are better than dry foods, because the canned food adds fluid to the diet. Prescription diets that are used for cats with kidney failure include Eukanuba MultiStage Renal, Purina Veterinary NF, Hill's Science Diet k/d, Royal Canin Modified Formula, and Royal Canin Renal LP 21. Your veterinarian can also guide you to appropriate homemade diets.
Phosphorous restriction in the diet is important, although phosphate binders, such as aluminum hydroxide salt (Amphogel) can also be given. Vetoquinol has produced a veterinary product called Epakitin that is a palatable powder that also binds phosphates. However, this product also contains calcium, which may be contraindicated in the later stages of renal failure.
Large amounts of B vitamins are lost in the urine of uremic cats. These losses should be replaced by giving vitamin B supplements. Sodium bicarbonate tablets may be indicated to correct an acid-base imbalance. Potassium may also need to be supplemented. The kidneys are also important in the production of vitamin D. Cats in chronic renal failure may benefit from the addition of calcitriol to their therapeutic regimen. Your veterinarian may need to order special compounded versions of calcitriol to get the appropriate dosage for a cat.
Vomiting may need to be controlled with medications such as famotidine, ranitidine, omeprazole, or others, until the renal condition is stabilized.
Erythropoietin may be used to help counteract the anemia associated with long-term renal failure. Currently, human recombinant erythropoietin is used, which may lead to immune-based destruction of red blood cells and a renewal of the anemia over time. Research is continuing for a safe feline alternative.
Cats with hypertension will need therapy to lower their blood pressure.
A uremic cat who becomes ill, dehydrated, or fails to drink enough water may suddenly decompensate; this is known as a uremic crisis. The cat should be hospitalized and rehydrated with appropriate intravenous fluids and balanced electrolyte solutions.
Some exercise is good for a uremic cat, but stressful activity should be avoided.
Another option to consider for cats with terminal kidney failure is a kidney transplant. Kidney transplants are only done at a few veterinary referral centers but are becoming more common. As with human transplant patients, drugs must be given post-transplant to prevent rejection problems. These drugs are quite expensive and must be carefully calibrated to minimize side effects. Also, it was recently reported that cats are at a higher risk for developing diabetes due to the use of these drugs.
The current method for finding kidney donors is to test shelter cats for tissue compatibility. The shelter cat then donates one kidney-cats, like people, can do fine with just one healthy kidney. The shelter cat is then adopted by the family of the recipient cat, who must agree ahead of time to provide a home for the donor cat for the rest of her life.
This article is excerpted from “Cat Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.
Copyright © 2008 by Delbert Carlson, DVM, and James M. Giffin, MD. All rights reserved.