Many treatment and diagnostic options found in veterinary medicine today started

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1 New Treatment Options for Kidney Disease By William E. Feeman III, DVM Many treatment and diagnostic options found in veterinary medicine today started originally as treatment or diagnostic options for humans. As the demand for cutting-edge diagnostics and treatments have increased over the years, many of these technologies and procedures have been used in veterinary medicine. Two cutting-edge procedures extrapolated from human medicine in the treatment of kidney disease will be discussed in this article. Kidney disease is a condition that has affected many dog owners over the years. When the kidneys fail to function adequately substances can build up in the blood that can make animals feel sick. Sick animals may show signs of increased drinking to severe lethargy. Most causes of kidney disease are not curable and supportive measures are taken to extend the dog s quantity of life and improve the dog s quality of life. Supportive measures include prescription kidney diets, subcutaneous fluid administration and medications such as stomach acid reducers and phosphorous binders. Severe cases may require hospitalization and intravenous fluid therapy. Two rare treatment options available now which may help in some cases of kidney disease are kidney transplantation and kidney dialysis. Kidney transplantation replaces the diseased kidney with a new functioning kidney whereas kidney dialysis artificially replaces some of the filtering functions of the kidneys. Kidney transplantation is a very rare procedure in a dog. Some referral facilities may perform this surgery weekly on cats but only very rarely on dogs. The primary

2 reason for this is the rejection of the organ by the recipient. Immunosuppressive drug therapy is less dependable in dogs than it is in cats. Transplantations are never performed on an emergency basis and patients must be stabilized prior to surgery. Early referral before significant complications of end stage kidney disease develop is preferred. The cost of the procedure can be staggering. The surgery and its associated costs will often run in excess of $10,000 (unexpected complications could add additional expense). Following surgery, the animal will stay in the hospital for days. The recipient will need to be kept on a regimen of immunosuppressive drugs which normally cost $150/month for small dogs and up to $2000/month for giant breeds. Most institutions that will perform kidney transplantation surgery ask that the recipient s family also find an appropriate donor dog. A donor dog can be obtained by some institutions but the recipient s family will need to pay for all testing related to the transplantation and will have to provide a home for the dog and care for it after surgery. Ideal donors should be less than 6 years of age, healthy and of similar size and body weight to the recipient. It is preferable if the dogs are of the same breed but is not a necessity. Donor dogs can live perfectly normal and healthy lives after surgery. Following surgery, the recipient will require twice daily medications and will require weekly blood tests (these are not included in the surgical estimate). Based on the results of these tests, the frequency of testing and immunosuppressive medication may decrease over time. The major complications associated with transplantation surgery include: acute rejection of the donated kidney, infection and side effects associated with the immunosuppressive drugs (liver toxicity, bone marrow suppression, vomiting, diarrhea and cancer). Immunosuppressive drugs following organ transplantation have

3 been associated with a one hundred fold increase in cancer in humans. Approximately ten percent of cats undergoing a kidney transplant will develop some form of cancer which is believed to be associated with the use of immunosuppressive drugs. It is assumed that dogs may have a similar increase in risk of cancer. Kidney dialysis is a treatment option that is offered by a few referral clinics nationally. In this procedure, blood is pumped out of the body and various substances are filtered out before returning to the body. Approximately 50% of patients treated with dialysis will show clinical improvement after the treatment (increased appetite, increased energy level, etc.). Dialysis requires placement of a large indwelling intravenous catheter that may require surgery. The cost associated with kidney dialysis can be prohibitive in many instances. The first week of treatment will typically cost $2500-$3000 and would include catheter placement, the first three treatments and feeding tube placement if needed (some animals may require a feeding tube to ensure adequate nutrition). Subsequent treatments cost $500/treatment and most animals require three treatments/week. Complications associated with dialysis are numerous. Malnutrition is a primary concern. Many animals with kidney disease have a poor appetite. Treatment with dialysis may or may not improve appetite but it will increase protein and calorie requirements. These increased requirements may necessitate the use of a feeding tube. Patients undergoing dialysis have a higher risk of broken bones, carnitine and taurine deficiency (two nutrients associated with heart disease when the levels are low), blood clot formation in the dialysis catheter and infection from the dialysis catheter.

4 Dialysis has been slow to transition from human medicine to veterinary medicine because new equipment had to be developed for its use. Standard human dialysis machines would extract too much blood from a veterinary patient, which could be lethal. The research and development of veterinary dialysis machines is what keeps the price relatively high. Kidney transplantation and kidney dialysis are two cutting-edge procedures available to animals with kidney disease. There are very few hospitals that are even able to provide these services and they do so at great expense. Current research funded by the Morris Animal Foundation (see attached information sheet) is seeking to improve on these treatment options. As more procedures are performed and more studies are conducted, these cutting-edge procedures may become main stream treatments.

5 Table 1. Laboratory tests required of the recipient and donor prior to kidney transplant surgery. Recipient Complete Blood Cell Count Serum Biochemistry Profile Urinalysis Urine Culture and Sensitivity Urine Protein:Creatinine Ratio Heartworm Antigen Test Toxoplasmosis Titer (IgG and IgM) Thyroid Test Echocardiogram Thoracic Radiographs Abdominal Ultrasound Coagulation Panel Antithrombin III And Fibrinogen Levels Blood Pressure Fecal Examination Donor Complete Blood Cell Count Serum Biochemistry Profile Urinalysis Urine Culture and Sensitivity Heartworm Antigen Test Toxoplasmosis Titer (IgG and IgM) Intravenous Pyelogram Blood Type and Cross-Match To Recipient Table 2. How to find an institution that will perform canine transplantation surgery. Find a center close to you that performs feline transplant surgery and ask them if they have/will perform the surgery on a dog. You can find a list of institutions that will perform feline transplantation surgery at: Your primary veterinarian may also be able to recommend a specific facility. Table 3. List of active hemodialysis centers. Hemodialysis Centers University of California, Davis, CA Helen Woodward Animal Center, Rancho Santa Fe, CA The Animal Medical Center, New York City, NY University of Pennsylvania, Philadelphia, PA Tufts University, North Grafton, MA

6 References Screening Renal Transplant Recipients: Life and Death Decisions Western Veterinary Conference Christopher A. Adin, DVM, DACVS Ethics of Kidney Transplants in Cats and Dogs. Vet Rec 152 [21]: Williams DL, Darling F Transplantation Tolerance in the 21 st Century: The Art of the Impossible? ACVIM Oliver A. Garden, BSc, BVetMed, PhD, MIBiol, MRCVS, DACVIM Dialysis: What Do I Need To Know? Western Veterinary Conference Christopher A. Adin, DVM, DACVS Dr. Feeman is a 2002 graduate of The Ohio State University of Veterinary Medicine and currently practices in Ohio. He is an active volunteer for Greyhound Adoption of Ohio and a member of Veterinarians for Retired Racing Greyhounds.