Chronic Renal Failure In Senior Cats and Dogs

Chronic Renal Failure (CRF) is a relatively common malady in senior pets. Though cats are affected more often than dogs, it can be a debilitating disease in either species. However, with proper care, our companions can have many years of high-quality life once a diagnosis is made. In this article, we are going to explore the functions of the kidneys, and the causes, treatments, and possible preventions of CRF.

The Functions of the Kidneys

The 2 kidneys are remarkable organs that assist in keeping the body in metabolic balance and maintaining blood count as well as eliminating waste products from the blood. The functions of the kidneys include: 1) Regulating the amount of fluid in the blood, 2) Maintaining blood concentration in the correct range, 3) Eliminating waste products the body produces from the metabolization of food, 4) Keeping the concentration of salts in the blood normal, and 5) Producing a chemical called Erythropoietin which stimulates the production of red blood cells and prevents anemia.

What is Chronic Renal Failure?

Chronic Renal Failure is a slow loss of kidney function. It is distinguished from acute renal failure, which is a very rapid loss of kidney function. The decrease in kidney function in CRF occurs over years as opposed to acute renal failure, which has a time course of days to weeks. Because the decrease in kidney function in CRF takes place over a long period, severe, irreversible damage has usually occurred by the time pets are symptomatic and the disease is diagnosed.

How Do Kidneys Work?

Think of the kidneys as the world’s most incredible and effective filtration system. In the kidneys, blood flows through millions of tiny masses of capillaries called Glomeruli. Practically everything in the blood except blood cells-water, proteins, and salts-is removed from the blood and collected in millions of long tubes that run through the kidneys. As the filtered solution flows through these tubes what the body needs is reabsorbed into the blood. The rest, waste products, continue traveling through the tubes, are collected in the center part of the kidney, and become urine. The urine then flows from each kidney through the ureter to the bladder where it is stored until it is expelled.

What Goes Wrong in Renal Failure?

In renal failure, the kidneys’ ability to filter blood is diminished. Consequently, dilute urine containing much of what the body needs and little of the body’s waste products are produced and excreted.

The Causes of Chronic Renal Failure

There are many causes of CRF, unfortunately, in the majority of cases, the exact cause is never determined. Known causes of CRF include: 1) Hereditary conditions that result in abnormal kidneys, 2) Damage to the kidneys from injury, 3) Infections, both bacterial and fungal, 4) Toxins produced from bacteria or fungi during an infection, or ingested toxins, like antifreeze, 5) Obstruction to urine outflow which causes damage to the kidney from the backup of urine, 6) Medications (side-effects and overdoses), 7) Autoimmune diseases, and 8) Cancer. (High protein diets do not cause renal failure. This is a myth that has been around for some time, and has been proven untrue.)

The Signs of Chronic Renal Failure

Most of the signs of renal failure are general and nonspecific. They include dull coat, general fatigue, apathy, and tiredness, and lack of appetite. Increased thirst and increased urination are two of the most common signs and should be red flags prompting the investigation. It may seem strange that increased urination is a sign of kidney failure, but remember, the urine that is produced is not concentrated, rather, it is much more dilute than it should be.

How is CRF Diagnosed?

Your holistic veterinarian will do a complete history and physical exam, however, the diagnosis is made from testing your companion’s urine and blood.

Urine Tests

Urine is tested to determine its concentration and the amount of protein and glucose it contains. Specific gravity is a measure of the concentration of urine, and the higher the number, the more concentrated the urine. A normal specific gravity for a dog’s urine is 1.020 to 1.040, and for a cat, 1.025 to 1.050. In renal failure, the specific gravity is generally 1.008 (or lower) to 1.012.

Protein and glucose are usually not found in any amount in urine. In renal failure large amounts of both are present. Other abnormalities of the urine like the presence of blood cells or chemical crystals can give clues to the cause of renal failure.

Blood Tests

Blood is tested for the presence of Blood Urea Nitrogen (BUN) and Creatinine. Electrolyte levels and a blood count may also be done. BUN and Creatinine are normal metabolic waste products that are excreted in the urine. A normal BUN level is less than 25 mg/dL to 30 mg/dL, but in renal failure, it can be over 90 mg/dL. Similarly, Creatinine is usually present at a level of less than 1 mg/dL but is frequently over 8 mg/dL in advanced disease. A blood count will show anemia with advanced disease and levels of electrolytes like sodium and potassium may be abnormal.

Chronic Renal Failure In Senior Cats and Dogs

Treating Chronic Renal Failure

Unfortunately, little can be done to restore lost kidney function. While dialysis of the blood and kidney transplant is common in humans, they are less reliable options for animals and place a heavy financial burden on owners, and are incredibly stressful for pets. Fortunately, many things can be done to assist the kidneys and augment the remaining function to allow our companions an active and high-quality life.


In the past, it was thought a low protein diet was necessary for dogs and cats with renal failure. Today it is generally agreed that a low protein diet does not help, and can actually be harmful because your dog or cat’s protein requirements may not be met leading to malnutrition. Most people believe a diet with a normal amount of high quality, easily digestible protein is most beneficial. A diet of primarily raw, organic meat like chicken or turkey is an excellent choice for cats and beneficial for dogs as well. Dr. Pitcairn’s Guide to Natural Health for Dogs and Cats, by Richard Pitcairn, DVM, and Susan Pitcairn (ISBN 075962432) is an excellent resource that discusses the importance of a raw food diet and offers recipes, including ones for animals with renal disease.

There are some commercial foods, generally only available from veterinarians, formulated for cats and dogs with CRF. These diets are low protein formulas often containing poor quality ingredients. In fact, there are well-documented studies and research that prove that dogs and cats thrive on diets with levels of protein consistent with a carnivore’s natural prey selection.

Because water balance is so important and animals frequently require more than they will drink, it is best to feed high-moisture food. Cats especially need moist food and dry diets should not be fed. Cats will not naturally drink water to compensate for the lack of moisture in dry food leading to a constant state of dehydration.

With any diet, it is important that the nutrients in the food get absorbed and assimilated. Wysong F-Biotic Feline Enzyme and Probiotic Supplement and Animal Essentials All Natural Enzyme and Probiotic Supplement are both excellent choices to assure all of the nutrients in your companion’s food are getting where they need to be.


Omega-3 fatty acids have been shown to be beneficial in CRF and antioxidants are important, too. Halo offers several quality supplements: Anitra’s Vita-Mineral Supplement, which supplies the water-soluble vitamins, Dream Coat Essential Fatty Acid Supplement, for Omega 3, 6 and 9’s and X-tra C Instant Vitamin C Powder for the antioxidant benefits.

Renafood by Standard Process and Renal Essentials by Vetriscience, are veterinary prescribed supplements that are good renal detoxifiers and assist in maximizing kidney function.

Kidney Glandulars and Protomorphogens are extracted from the kidney itself, and assist the body in detoxifying and promote kidney function

Nausea and Appetite

The abnormally high waste products in the blood cause cats and dogs to become nauseated, which leads to a decrease in appetite. A decrease in food intake makes an already bad situation worse. Since cats and dogs eat by their sense of smell, warming their food slightly will make it more appealing and help improve their appetite.

Subcutaneous Fluids

Though animals will drink more because their bodies are signaling them that more fluid is needed to carry away waste products, they frequently cannot, or do not drink enough. In emergencies, fluids must be given intravenously. Sometimes, in order to maintain an acceptable level of health, a small amount of fluid must be given daily under the skin. While this is not something most owners enjoy the thought of doing, it is not as difficult as it sounds, and animals don’t seem to mind as much as we think they would.


The blood is filled with many dissolved minerals, called electrolytes. Many of these may become out of balance in renal failure. Smartwater, bottled water by Glaceau, found at all major grocery chains can be given to aid in restoring electrolyte balance.

Phosphate binders are used to decrease the absorption of phosphates which are normally present in food, and which the kidneys have difficulty with when they are not functioning properly.

Potassium supplements are sometimes necessary as this element is frequently lost in the urine.


Erythropoietin is the hormone produced by the kidney that stimulates the production of red blood cells. It is decreased in renal failure and the reason animals become anemic. Injections 2 to 3 times a week will dramatically improve anemia. The downside is that the only commercially available preparations are human and animals can develop a reaction to them over time. For this reason, it is only used once anemia is severe.

Blood Pressure

Blood pressure can increase in advanced disease and sometimes medications to control hypertension are necessary.


Stress in our animal’s lives can affect their metabolism and worsen renal failure. Providing them a stable, consistent environment is extremely important.

Herbs, Homeopathics, and Flower Essences

There are many alternatives to traditional medications to support kidney function, both as preventatives and once a renal failure has occurred. (Check out Vetsimo’s article about herbal treatments for cats and dogs)

Herbs useful for strengthening kidney function include goldenrod, juniper, and parsley. A tea of 1 part each of hawthorn, ginkgo, echinacea, marshmallow, and dandelion leaf is useful for treating renal failure. Animals’ Apawthecary Senior Blend Herbal Tincture is a tonic for diminished kidney function and strengthens the nervous, digestive, circulatory, and immune systems.

There are many Homeopathic remedies useful for CRF. Some are Apis Mellifica, Arsenicum Album, Bellis Perennis, Cantharis, and Lycopodium. Combination remedies are also available. Your holistic veterinarian can prescribe the best remedies for your pets’ individual needs.

Flower Essences can also be useful in detoxifying, promoting kidney function, and reducing stress. There are many wonderful and qualified Flower Essence practitioners that can help identify the correct essence or blend for your pet. Visit the World Wide Essence Society to find a practitioner near you:


There are no true preventative measures to assure your companion will not be affected by renal failure. As with all potential medical conditions, the best prevention is a species-appropriate diet consisting of high-quality protein, essential fatty acids, vitamins, minerals, and enzymes. Exercise, fresh clean water, and air and a calm loving environment are also essential. All the same, things we do to keep ourselves happy, healthy and disease-free apply to our pets. In addition, regular visits to your holistic veterinarian will help identify minor problems before they become major ones.

Early Warning

There are unfortunately no early warning signs of renal failure. If a cat’s BUN becomes greater than 35 mg/dL and the Creatinine increases to 1.8 mg/dL to 2.0 mg/dL, less than 25% of kidney function is left. The best early warning is to be a keen observer of your companion and discuss any changes in their behavior with your holistic veterinarian.

Quality of Life

The treatment goal of CRF is to provide the best quality of life possible for our companions under the circumstances of a potentially debilitating disease. With early detection and proper care, nutrition, and most of all, love, our friends can still have magnificent golden years.


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