Common Problems Related to CRF

Metabolic acidosis occurs in CRF cats because the kidneys cannot rid themselves of excess acids from the diet. Ionized Hydrogen (H+) builds up in the blood. The body buffers this by combining the H+ with bicarbonate (HC03-), causing the bicarbonate levels to fall. Bicarbonate can be measured as part of a blood gas analysis, which requires specialized equipment. However, a good approximation can be done as part of a blood test by measuring total Carbon Dioxide (CO2). Since about 95% of total CO2 in the blood is bicarbonate, when bicarbonate levels fall, so does total CO2. When using this method, care must be taken to be certain that there is no air in the tube above the sample as the CO2 in the air will alter the reading. Metabolic acidosis is treated by raising bicarbonate levels either by using bicarbonate or citrate which is a metabolic precursor to bicarbonate.

Nonregenerative anemia is quite common with CRF cats, especially as the disease progresses. The cat's kidneys normally produce the hormone erythropoietin which stimulates the bone marrow to produce red blood cells. CRF lessens the production of erythropoietin and the bone marrow is less stimulated, thereby causing the cat to become anemic. Anemia can be monitored with blood tests. Learn the normal color of your cat's mucous membranes and check daily for signs of anemia. If the gums, tongue or nosepad appear pale or bluish in color, contact your veterinarian immediately for the necessary treatment. Cats with anemia are also weak and may have rapid breathing and loss of appetite. Medications are available to treat anemia. Transfusion is an option, but must be repeated frequently, is stressful for the cat and is only a short-term solution.

Loss of appetite (see Stomach Irritation) is a common problem with CRF cats and it can be extremely frustrating to the caregiver(s). The cat won't eat because it doesn't feel good and not eating makes it feel even worse and lose weight. An appetite stimulant or force-feeding may be needed as time goes on.

Constipation can be a painful problem for CRF cats. While constipation can have many varied and quite serious causes (such as megacolon), dehydration and inadequate water intake may be the most common causes of constipation in CRF cats.

Talk to your vet about your cat’s constipation and what feline medications and other measures such as adding fiber to the diet will relieve it. Increasing fluid intake by feeding your cat canned food, adding water to dry food and administering sub-Q fluids all may be helpful. The most well-known feline constipation medication is Lactulose which must be prescribed by your veterinarian. NEVER give your cat a human laxative or enema by yourself. This procedure should only be done by a veterinarian.

Dehydration is an abnormal depletion of body fluids that is usually a constant problem for CRF cats because the kidneys cannot concentrate urine. The problem becomes more serious with excessive or chronic vomiting and/or diarrhea. To check for dehydration, gently pinch a bit of skin at the back of the cat's neck. When released, it should immediately fall back in place. If it takes a few seconds, it's indicative of loss of elasticity which is a characteristic of dehydration. Another test for dehydration is to touch the cat's gums. They should feel slick. If they feel tacky, the cat is dehydrated. Be aware that only cats who are SERIOUSLY dehydrated show these symptoms. Cats can be significantly dehydrated before clinical signs are obvious. If your cat is dehydrated, you should contact your vet as soon as possible. You may have to begin subcutaneous fluid therapy, or, if you already giving sub-Q fluids, you may need to increase the frequency or volume.

The parathyroid glands maintain a balance of phosphorus and calcium levels. During CRF, high levels of phosphorus accumulate in the blood (hyperphosphatemia) because the kidneys can no longer efficiently excrete it. When phosphorus is excessive, the parathyroid glands produce more of the parathyroid hormone (PTH) in an attempt to restore a calcium/phosphorus balance. The overproduction of PTH results in calcium being removed from the bones to balance the excess phosphorus.

Hypertension, abnormally high blood pressure, can be either a cause of CRF or be caused by CRF. It occurs when the kidneys are unable to excrete sufficient quantities of sodium. It can be diagnosed by taking the cat's blood pressure or by an ophthalmologist. Hypertension can cause further kidney damage or damage to other internal organs, cardiovascular problems, seizures, retinal lesions, retinal detachment and blindness.

Retinal detachment, in which the retinas develop cysts and detach, is common in CRF cats. Unfortunately, visual impairment may not be recognized until retinal detachment occurs and the cat becomes blind and disoriented. This condition is usually treatable and can be controlled with medication if hypertension is diagnosed early.

If blindness caused by detached retinae occurs, it can sometimes be reversed partially or even fully if high blood pressure medication is given within a day or so of onset. It is crucial to take your cat to your veterinarian as soon as possible if you suspect that your cat is having vision problems.

Hypokalemia (potassium depletion) can result from chronic vomiting and excessive urination. Unfortunately, most CRF cats eventually become hypokalemic. It can occur quickly and the cat may have a generalized muscle weakness or possibly weakness in the hindquarters. There may also be an inability to hold the head up, an awkward gait, stiffness, an unwillingness to move and the cat may tire easily. Other symptoms may resemble some of the symptoms of CRF, including anorexia, weight loss and anemia. Potassium depletion can be controlled with potassium supplementation.

Hyperkalemia (excess potassium) may result from the inability of the kidneys of end-stage CRF cats to sufficiently rid their bodies of excess potassium. Hyperkalemia can stress the heart and could potentially cause heart failure and/or other associated problems. It is crucial to always consult your veterinarian when supplementing potassium, whether your cat is in the early, middle, or end-stage of CRF.

Mouth and tongue ulcers, common in CRF cats, can cause discomfort and may prevent a cat from eating, thus causing substantial weight loss. In some cases, ulcers may extend into the esophagus. There may be an indicative odor from the cat's mouth. The mouth should be checked frequently by you and your veterinarian. Antibiotics and human ulcer medications (compounded to cat-size dosage) are available to heal mouth ulcers.

CRF cats tend to have a buildup of excess stomach acid and this can be a real factor in depressed appetite. At some point, vomiting may become a serious and ongoing problem due to nausea caused by blood chemistry or increased bile/gastric acid production. Vomiting causes dehydration and loss of potassium. The cat may lick its lips frequently as if trying to get rid of a bad taste. Some CRF cats tend to vomit clear liquid on a regular basis. Anti-ulcer drugs and protective agents may alleviate the nausea enough so that the cat regains its appetite.