Kidney Failure (Chronic Renal Failure) Adapted from The Pet Health Library by Wendy C. Brooks, DVM, Dipl. ABVP Educational Director, Veterinary Partner.com What You Should Know If My Pet is Still Making Plenty of Urine, How Can There Be Kidney Failure? In chronic renal failure, or CRF, urine is usually produced in excessive quantities. What the kidneys are failing to do is conserve water (they are failing to make concentrated urine). The body produces numerous toxins on a moment by moment basis. These toxins circulate to the kidneys where, dissolved in water, they are filtered out and urinated away. An efficient kidney can make a highly concentrated urine so that a large amount of toxin can be excreted in a relatively small amount of water. When the kidneys fail over a long time period, they lose their ability to concentrate urine and more water is required to excrete the same amount of toxin. Your cat will begin to drink more and more to provide failing kidneys with enough water and ultimately, they will be unable to drink enough. Toxin levels will then begin to rise. Weight loss, listlessness, nausea, constipation and poor appetite may become noticeable. It is common for animals, especially cats, to have a long history of excessive water consumption when they finally come to the veterinarians office with one of the latter complaints. What Is My Veterinarian Reading on the Labwork? If you wish to understand your pet’s status with regards to kidney failure, it is important to understand some of the parameters being monitored. Urine Specific Gravity - Blood Urea Nitrogen (BUN) - This is a measure of how concentrated This is a protein metabolite excreted by a urine sample is. Water has a specific the kidney (it is one of the toxins we are gravity of A dilute urine sample concerned about). In a normal animal, has a specific gravity of less than the BUN is 12 – 30. In renal failure, A concentrated urine sample would BUN may range from 40 – 90 when have a specific gravity over diagnosed at an early stage, or over when diagnosed at an advanced stage. 81 Webb Street, Salem, MA (978) 744 – 8020 Kathleen K. Ternes DVM, DABVP Elaine M. Bird, DVM Holly E. Willard, DVM

Creatinine - This is another protein Phosphorus – The calcium/phosphorus Metabolite (though this one is less balance becomes deranged in kidney failure dependent on dietary protein intake due to hormone changes that ensue as well than BUN). A normal creatinine is as the inability of the failing kidney to less than 2.3. BUN and creatinine excrete phosphorus. If calcium and phos- Will be monitored (as well as several phorus levels become too high, the soft Other parameters) over time and in tissues of the animals’ body will develop response to different treatments. mineralized deposits which are inflammatory and uncomfortable. The bones will weaken as well. Medications and special diets can be used to keep phosphorus levels down. Potassium- The failing kidney is Unable to conserve potassium efficiently and supplementation may be needed. Signs of hypokalemia (the Scientific term for low blood potassium) Includes weakness, especially drooping of the head and neck and poor appetite. Packed Cell Volume/Hematocrit- This is a measure of the percentage of blood made up by red blood cells. The hormone that stimulates the production of red blood cells is made by the kidney. The failing kidney does not make this hormone in normal amounts and anemia can result. Anemia is often worsened by the extra fluid administrations needed to manage the kidney toxins. Sometimes, a blood transfusion is needed or, more commonly, the owner of the pet can learn how to give hormone injections to boost the red blood cell count. Blood Pressure- Blood pressure is checked in the exam room with a Doppler monitor and it is important to monitor in kidney patients as there is a tendency for hypertension to develop in kidney failure. Special medications may be needed to manage this problem should it arise. Untreated high blood pressure can cause retinal damage/detachment resulting in blindness. What Are The Treatment Options? What one does to address this problem depends on its stage at the time of diagnosis. More advanced cases will require hospitalization for a cycle of diuresis where fluids are delivered intravenously for 48 – 72 hours and the above parameters are rechecked. The goal is to stabilize the patient at a toxin level where a good quality of life can be experienced. Milder cases can be managed with fluid administration under the skin (subcutaneous fluids) at home. Some cats will tolerate this procedure well.

What Sort of Treatments Might My Cat Require At Home? Special Diet- Most prescription diet companies produce a diet with restricted protein (so as to generate less BUN), restricted phosphorus, and with other important qualities to promote metabolic health in patients with compromised kidneys. Hills Prescription Diet K/D canned and dry food, Purina Veterinary Diets NF canned food and Royal Canin Renal LP Modified canned food are all types of diets we can offer to kidney patients. Fluids Under the Skin- Giving subcutaneous fluids is a technique important to learn, as many cats in kidney failure require this treatment at some point in their lives. If this process is recommended for your cat, you will receive lessons on how this technique is preformed. Usually, once your cat starts fluid treatment, it will continue to be on some form of it for the rest of its life. This could be once a day, once every other day or a few times a week. The frequency depends on how your cat responds to treatment. This can be determined by rechecking blood values. Potassium and B vitamins may also be added to the fluids for extra benefits if needed. Epogen (Erythropoeitin)- The hormone that the kidneys have failed to produce can be replaced by this manufactured injectable hormone. It stimulates the production of red blood cells. This can be done at home 2 – 3 times a week. Alucap (Phosphate Binders)- Alucap is an antacid caplet used for stomach upset. It also binds phosphates in the diet when it is given with food. This reduces the phosphorus intake from the GI tract and helps normalize the blood phosphorus level. Norvasc (Amlodipine)- This blood pressure medication is of the calcium channel blocker type. It is commonly used in hypertensive cats with kidney issues. Benazepril (Lotensin) is another medication that is used alone or in conjunction with Amlodipine to decrease vasotension to the renal artery and increase blood flow to the kidney. This results in more efficient kidney filtration. Appetite Stimulants- Many kidney failure cats have a decreased appetite. Periactin (Cyproheptadine) and Remeron (Mirtazapine) are appetite stimulants that may be used on and off during treatment to help maintain a healthy appetite. Potassipowder/Potassitabs- These potassium supplements are available in powder or tablet form. If a patient is not maintaining a normal potassium level, these may be prescribed.

Pepcid- This is a human drug that comes in tablet form. It is safe to use in cats. It helps to ease nausea and prevent stomach ulcers that can occur with kidney failure. Antibiotics- Kidney failure can make your cat more susceptible to kidney and urinary tract infections. Antibiotics may be used to help prevent or treat an already existing infection. Follow-up Labwork After Initial Diagnosis:  Periodic bloodwork to monitor renal values.  Packed Cell Volume/Total Protein to monitor anemia - more frequently if your cat is being treated for anemia.  Electrolytes to monitor sodium, potassium and chloride levels, especially if your cat is on a potassium supplement.  Urinalysis to monitor urine specific gravity and periodic urine cultures to rule out urinary tract infections (to which kidney failure cats are very susceptible and are very dangerous to them).  Blood pressure, routinely, to monitor for hypertension - more often if your cat is being treated with medication for hypertension. Kidney failure is a complicated disease with many facets. Please do not hesitate to call The Feline Hospital should you have any questions or problems at home. You Are Not Alone: Further Resources Chronic renal failure is a common disease and there are many pet owners just like you, all sharing thoughts, tips and information over the internet. If you are interested in exploring these resources, here is what is available:  is a vast source of information compiled by the owner of Avatar, a cat who ultimately succumbed to his kidney failure.  An online mailing list for owners of cats with kidney failure is available at Sign up to subscribe.  is another resource including candid experiences with CRF treatments.