Kidney Disease

The main function of the kidney is to remove metabolic poisons and waste products from the body’s blood supply. The kidneys act as in-line filters for the blood stream.

All of the body’s blood circulates through the kidneys eventually. There it is cleansed of all chemicals not needed by the body. The kidneys filter the blood in two steps. In the first step, nearly all of the dissolved chemicals are removed from the blood. In the second step, some of the desirable items such as blood sugar, most of the water, and certain other essential substances are returned to the blood stream. All of the chemicals that were filtered out of the blood in the first step and not returned to the blood in the second step are excreted as urine.

That’s the way it is supposed to work. But kidney disease changes things. Kidney disease is an insidiously progressive disease that destroys the kidney. Causes of kidney disease include birth defects, bacterial or viral infections, injury, certain medications, poisons, kidney stones, bladder stones, cancer and many other things. Frequently, the cause cannot be determined. If the kidneys are damaged severely, they will not be able to perform properly, so waste materials accumulate in the blood, poisoning the body.

Signs of kidney disease become apparent once damage reaches the point at which the kidneys cannot rid the body of the metabolic waste products that accumulate continuously, or when the delicate fluid/electrolyte balance of the body cannot be maintained. This point varies from pet to pet, but in general, 2/3 of the functional kidney mass must be lost before symptoms of kidney disease become apparent. Once a kidney is damaged, regeneration does not occur.

It is important to remember that the body can continue to function fairly normally as long as there remains at least 10% functional kidney tissue. In our experience, many pets are able to live out fairly normal lives with kidney disease as long as it is detected early, and proper treatment and diet changes are started promptly.

Signs of kidney disease can appear suddenly or develop slowly over time. Other diseases can also produce the same constellation of symptoms. Initial signs of kidney disease include: malaise or lethargy, loss of appetite, poor or unkempt haircoat, increased water consumption (often overlooked in cats), and increased urination

Later signs include vomiting, diarrhea, depression, and dehydration. This latter development 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. Dehydration results from an inadequate amount of water in the body, from water loss due to vomiting, from inability to drink and/or from excessive urine output.

Vomiting, diarrhea, and difficult breathing appear as the disease progresses with a buildup of waste products in the blood stream. Anemia may occur in severe cases because hormones from the kidneys are involved in the production of red blood cells.

Treatment: Treatment of kidney diseases is general focused on the following general concepts:

Maintenance of proper hydration and water intake.

Dietary optimization.

Stress avoidance.

Elimination or minimization of other treatable concurrent problems that may be interfering with kidney function. This includes things such as:

Infection

Partial or complete urinary output obstruction

Heart disease

Electrolyte imbalances

Maintain access to fresh, clean, water at all times. Change the water daily.

Protect your pet from environmental and psychological stresses. These would include such things as extreme exertion, excitement, excessively hot or cold temperatures, new household pets, kenneling, long trips, excessive exercise, etc.

Diet optimization is one of the cornerstones of kidney disease management.

Feed only Prescription Diet k/d® or Prescription Diet u/d® as directed. 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 k/dÒ or u/dÒ, 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 k/dÒ or u/dÒ,.

All of these special diets - k/dÒ or u/dÒ,, and the homemade diets - should be supplemented with additional amounts of the water-soluble vitamins (B & C) and zinc.

Additional medications may be required depending on the severity and type of kidney disease present.

Some patients require an oral phosphorous binder to help reduce blood phosphorous levels.

Some patients require medication to suppress vomiting.

Some patients require medications to help acidify the blood.

Some patients require genetically engineered medications to reverse their anemia.

Other require a special type of vitamin D_{3 to help normalize calcium balance.}

Repeat kidney tests and urinalysis every 30-60 days, until your pet’s condition has been stabilized, and then every 3-4 months from then on.

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.