The Vocabulary of this Disease
Acute means short term. Chronic means long term. Renal means kidney. Insufficiency means reduced ability to perform an allotted function. Failure means inability to perform a task adequately. Acute kidney failure, also called acute renal disease and indicates the damage to the kidneys is recent. Chronic kidney failure, also called chronic renal failure, refers to the situation where the kidneys have not been able to perform at least one of their many tasks adequately for an extended period of time (months to years). Uremia means an excess of urea, creatinine and other metabolic waste products present in excess amounts in the blood. Because the word failure evokes such a sense of doom, many veterinarians use the term chronic renal insufficiency, as many cases can be treated successfully and can look forward to months or often years of quality life.

What does the kidney do?
any people have no idea what kidneys do except they have something to do with urine production. In fact, the kidneys are involved in water regulation, red blood cell production, regulating blood pressure, balancing salts, activating Vitamin D, and removal of toxic wastes the body produces.

The kidneys produce several substances and hormones that help regulate the body’s cellular functions. These substances and hormones influence heart rate, blood pressure, red blood cell production, thirst and hydration. All cellular functions are affected at some level of kidney failure.

The waste products the kidneys filter come from the normal metabolism and the breakdown of food for energy and production of new (or replacement) tissue (growth or self-repair). As the kidneys filter the blood they remove a combination of waste products, electrolytes, minerals and other substances that the body can still use from the blood. As these substances make their way through the kidney’s filtering system, it will measure and reabsorb a significant portion of those substances that the body can reuse and return them to the blood. The remaining products are eliminated in the urine.

Renal insufficiency or failure occurs when the kidneys can no longer remove toxic wastes from the body. These substances build up and symptoms of excess thirst, nausea, pain, weakness, appetite loss, intestinal bleeding and even seizures develop. Below is the description of each stage of renal disease.

What is renal (kidney) insufficiency?
Renal insufficiency is the early stage of renal failure. By the time we diagnose renal insufficiency the kidneys have lost 75 – 85% of their function, reducing their ability to remove waste products and extra water from the blood. Returning reusable products back to the blood is becoming difficult. Laboratory tests may be normal or show mild abnormalities. Your pet may be showing mild signs of renal disease including reduced appetite, mild weight loss, excessive water consumption and excessive urination. Although these symptoms sound easy to identify, the truth is they can be missed by the owner because the symptoms are usually very minor. Often owners dismiss the symptoms as signs of old age.

What is renal (kidney) failure?

Renal failure occurs when the kidneys have lost greater than 85% of function. This means that the kidneys are having difficulty removing waste products, electrolytes, minerals, proteins and other substances from the blood. It is also having difficulty returning those substances that the body can reuse to the blood. This causes waste products to build up in the body and the loss of water and reusable substances. It is at this point that we see changes in the blood work.

There are numerous causes of renal failure and can include antifreeze poisoning, other types of poisoning, raisins, trauma, severe infection, certain drugs, numerous diseases and genetics (inherited from relatives). Renal failure in young patients can be related to congenital (birth defect), infectious or toxic causes. Older patients with renal failure can be due to degenerative, infectious, toxic or neoplasia (cancer). Inheritance also plays a role in older patients as well. Old age is not a “disease”, it is not the sole reason older animals develop kidney disease. Cats and dogs present with the same symptoms. However, cats are more prone to kidney disease and certain pure breeds of cats are more likely to develop it (i.e British shorthair, Birman, Somali cats of Asian descent and Angora). Many cats with renal insufficiency or failure are hypertensive (have high blood pressure) and will need medication to mange it. Every time your pet comes in for an appointment or lab tests its blood pressure and weight should be checked.

Acute renal failure is where there has been a rapid deterioration of kidney function over several days to weeks. Acute renal failure may be reversible depending on degree of damage the kidneys have sustained. It is possible for acute renal failure to progress to chronic renal failure.

Chronic renal failure has been present for months to years causing loss of renal tissue. Chronic renal failure is rarely reversible and is usually not curable. In chronic renal failure something is abnormal about the structure or function of one or both kidneys. By the time most chronic renal failure is diagnosed, the kidney has already lost at least 85% or more of its ability to filter the blood. It is often impossible to determine the original cause of the kidney damage at this point.

How is renal failure diagnosed?
We start with the physical exam and discussion with the owner to identify symptoms. Patients that have renal failure can present with weight loss, dehydration, vomiting, ulcers in the mouth, anemia, weakness, lethargy, drinking excessively and urinating excessively. Blood pressure measurement is also important because animals in renal failure may also have high blood pressure.

Our next step is lab work. Blood and urine tests are used to determine if kidney failure is present and possible cause of the kidney failure. Sometimes a biopsy of the kidney is recommended. However, the cause of kidney failure is not easy to determine and we may not be able to find the cause. Below you will see the list of diagnostics (lab tests) that we use to help diagnose renal disease.

A chemistry profile will give us information on kidney, liver, pancreas and adrenal function. It will provide us with information on mineral and electrolyte balances. This allows us to determine the stage of kidney disease present and provide treatment.

The complete blood count (CBC) will provide information that will tell us if your pet is anemic or dehydrated. Infection can sometimes be identified as well.

Thyroid function test will tell us if your pet has hypothyroidism (dogs) or hyperthyroidism (cats). Thyroid disease is a common cause or symptom of renal failure.

Serology – this type of lab work is looking for leptosporsis, ehrlichia, Rocky Mountain Spotted Fever, and specific parasites.

A urinalysis will provide additional information on kidney and bladder function. The specific gravity of the urine along with the chemistry profile will give us an idea of how well the kidney is concentrating the urine and getting rid of the waste products.

A culture and sensitivity of the urine will determine if there is an infectious cause of the renal failure. It will identify the bacteria and provide us with information on the type of antibiotics to use.

Performing radiographs (X-rays) and an ultrasound exam will allow us to determine kidney size, shape and architecture. It will allow us to see most kidney and bladder stones, visualize an obstructed bladder or kidney, and examine other organs in the abdomen.

What are the symptoms of renal disease?
Signs of kidney disease can appear suddenly or develop slowly over time. Other diseases can also produce the same type of symptoms. Initial signs of kidney disease include: lethargy (laying around or tired all the time), loss of appetite, poor or ragged hair coat, increased water consumption (often overlooked in cats), and increased urination.

Later signs include vomiting, diarrhea, depression, and dehydration. The dehydration is often surprising to pet owners as they usually see their pet drinking lots of water. However, most pets with kidney disease simply can’t drink enough to make up for what they are losing in their urine. Vomiting, diarrhea, and difficult breathing appear as the disease progresses with a buildup of waste products in the body. Anemia (low numbers of red blood cells) may occur in severe cases because hormones from the kidneys are involved in the production of red blood cells.

What treatments are available?
Treatment for renal failure varies with severity of the disease. The possible medications and treatment are listed below. Your pet may require only a few of these treatments or all of these treatments. The goal of treatment is to help the kidneys filter toxins out of the blood, resolve or reduce the uremia and attempt to bring the patient back to an earlier stage of disease and maintain a good quality of life for as long as possible.

The initial treatment is usually IV fluids to treat dehydration, replace electrolytes and flush out waste products that have built up in the tissues. Diuretics (Lasix) may be used to increase urine production and removal of waste products while the pet is on IV fluids.

Antacids (famotidine) are used to reduce the gastric acids and to stimulate your pet’s appetite by resolving nausea produced as a side effect of kidney disease.

Anti-emetics are used to stop or reduce vomiting and nausea. Reglan or Cerenia are two common drugs commonly used.

Gastroprotectants like Sucrafate (a/k/a Carafate) or Gastricalm will protect inflamed and ulcerated areas in the stomach by covering them so stomach acids does not cause additional injury. Inflammation and ulceration usually occurs when the phosphorus is high.

Potassium is an electrolyte that the failing kidney is not able to reabsorb. It is a vital electrolyte for the body. We recommend supplements containing potassium gluconate such as RenaKare, or Tumil-K to help maintain normal potassium levels.

Phosphate binders are used when the phosphorus is elevated. Elevated phosphorus can cause ulceration of the gastrointestinal tract. Amphogel or Renagel are two common phosphate binders that are used. Epakitin is a supplement that is mild phosphate binder and is sprinkled on the food.

Azodyl is a probiotic that is meant to help rid the body of urea (blood urea nitrogen also known as BUN on the blood chemistry test) and creatinine which would otherwise recirculate and again be filtered through the kidneys. By ridding the body of some of these toxins it will make your pet feel better, eat better, and have an overall better quality of life.

Calcitrol is a drug that is used to replace the natural calcitrol produced by the kidneys. If your pet’s kidneys are failing they are not making enough of this hormone. This will cause an imbalance of calcium and phosphorus in the body. There will be an excess of phosphorus and a lack of calcium. This imbalance is dangerous and usually happens in the late stages of kidney disease. The use of calcitriol should prevent the imbalance from occurring, decrease damage to the kidney and other tissues and provide a better quality of life.

Enalapril or benazepril (a/k/a ace inhibitors) are both heart drugs that cause dialation of blood vessels and allow more blood to be filtered by the kidneys. They also help to decrease the amount of protein loss in the urine. Protein loss in the urine can cause weight loss and additional damage to the kidney. Enalapril is used in dogs and benazepril is used in cats.

Amlodipine (Norvasc) is used to treat hypertension (high blood pressure) that can be found in 50% or more of cats that are in chronic renal failure.

Prescription diets are used in cats and dogs that have high urea levels. Diet modification is one of the cornerstones of kidney disease management.

Feed one of the following diets as directed by your veterinarian: Hills Prescription Diet k/d® or Hills Prescription Diet u/d®, or Purina NF or OM prescription diets. These diets are specially formulated to reduce the demands on the kidney. The highest quality protein available must be utilized to decrease the continuing damage occurring within the kidneys.

If your pet is a nibbler (most cats are), leave food available at all times. Otherwise, feed 3-4 small meals daily, rather than one large meal. Allow your pet to eat all that it wants, unless free-choice feeding causes obesity. If weight loss occurs in spite of good appetite, increase the amounts of dietary fats for cats or increase the amounts of dietary carbohydrates for dogs. Maintain your pet’s body weight at an optimal level. Your pet should be trim and have a marked waistline.

Warning: Many pets initially refuse the new food. BE PERSISTENT. Match wits with them. Dietary optimization is crucial for long-term maintenance. Getting your pet on the right food could literally add years to his/her life.

If your pet absolutely refuses to eat any of the prescription diets then try one of the homemade diets shown below. Be aware, however, that these homemade diets are not nearly as beneficial to the pet as the prescription diets.

All of these special diets and the homemade diets – should be supplemented with additional amounts of the water-soluble vitamins (B & C) and zinc.

Canine Restricted Protein Diet

  • ¼ lb. Ground beef (do not use lean ground chuck)
  • 2 cups cooked white rice, without salt
  • 1 hard cooked egg, finely chopped
  • 3 slices of white bread, crumbled
  • 1 t (5 g) calcium carbonate – (from ground egg shell or health food store)
  • Vitamin and Mineral supplement

Cook the beef in a skillet, stirring until lightly browned. Stir in the remaining ingredients and mix well. The resulting mixture is somewhat dry and its palatability can be improved by adding a little water (not milk). Keep covered in refrigerator. Yields about 1 ¼ lb.
Initially, feed at a rate of ¼ lb of food per 5 lb of body weight. Adjust up or down as necessary to maintain normal body weight.

Feline Restricted Protein Diet

  • ¼ lb liver (from beef, liver, or chicken only)
  • 2 large hard cooked eggs
  • 1 tablespoon vegetable oil
  • 1 t (5 g) calcium carbonate – (from ground egg shell or health food store)
  • 1/8 teaspoon KCI (salt substitute)
  • Vitamin and Mineral supplement
  • Taurine supplement – cats need about 250 mg/day

Dice and braise the meat, retaining all the fat. Combine all ingredients and mix well. The resulting mixture is somewhat dry and its palatability can be improved by adding a little water (not milk). Keep covered in refrigerator. Yields about 1 ¼ lb.
Initially, feed at a rate of ¼ lb of food per 5 lb of body weight. Adjust up or down as necessary to maintain normal body weight.

We HIGHLY recommend these web sites for good information on Feline CRF:
And you can find a fabulous support group with thousands of people who are treating their cats for CRF and have an incredible amount of good advice and moral support to offer:

The good folks at the Feline-CRF-Support group have been invaluable in providing very good technical information along with excellent emotional support


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  13. Articles from websites:
  14. Veterinary Partners – ( -articles on Renal Disease
  15. Veterinary Information Network – discussions and articles on Renal Disease