Gatti delle Foreste Norvegesi a Roma
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Symptoms of CRF
CRF can only be accurately diagnosed with clinical tests. There are some symptoms and behaviors that indicate the likelihood of CRF and, if these are observed, the cat should be tested as soon as possible. The most telling signs are increased thirst (polydipsia) and excessive urination (polyuria). As the condition progresses, your cat may experience loss of appetite, nausea and vomiting, weight loss, poor hair coat and emaciation. Only 30% of kidney capacity is needed for normal functioning. Therefore, no symptoms will be seen until approximately 70% of renal function is lost. It is important to begin treatment as soon as the first symptoms appear. Even with diet control, drugs and fluid therapy, you will eventually see at least some of the symptoms on the following list. Not all cats will exhibit all symptoms.
What is CRF?
Description of CRF (also called CRI, Chronic Renal Insufficiency)
Approximately 200,000 tiny structures (nephrons) in the kidneys eliminate waste products and regulate electrolytes in the body. CRF results when these nephrons begin to die off and waste products and electrolytes can no longer be processed effectively. The waste then accumulates in the cat's body. In effect, a cat in CRF is being poisoned by the waste that the kidneys are unable to filter. Electrolyte imbalances, anemia and blood pressure problems may also occur as the kidneys continue to deteriorate. The Kidneys
The kidneys have the following primary functions: 1. Filtering waste products from the body (primarily urea and creatinine).
2. Regulating electrolytes (potassium, calcium, phosphorus and sodium). 3. The production of erythropoietin, which helps to stimulate the bone marrow to produce red blood cells. 4. The production of renin, an enzyme that controls blood pressure. 5. Production and concentration of urine.
The Causes of CRF
CRF may have one or more causes. The common contributing factors are age, genetics, environment, and disease. In recent years, more attention has been directed towards high blood pressure, low potassium levels, acidified diets, and dental disease as possible contributors to the development of CRF. Research has indicated that some breeds have a higher rate of CRF than others. The Maine Coon, Abyssinian, Siamese, Russian Blue, Burmese, and Balinese appear to be more likely to develop CRF than other breeds. Although CRF can occur at any age, it is usually a disease of older cats. With dietary improvements in cat food, advances in feline medical care and more cats living indoors, cats are now living much longer and their bodies eventually wear out just as human bodies do.
Because there is no single, overwhelming cause of CRF, there is no definitive protocol for CRF prevention at this time. Not all cats will develop CRF. Statistical studies give hints about what may be helpful. However, since there are several possible mechanisms that may cause the onset of CRF, attempts at prevention may not be efficacious. Contributing FactorsAcidified Diet There is speculation that acidified diets, commonly fed to cats with lower urinary tract disease, may reduce absorption of potassium and thus contribute to hypokalemia and either cause or aggravate metabolic acidosis. Potassium Imbalance Low potassium is a possible cause of CRF and, at the very least, may be an early warning sign. It has been suggested by some veterinarians that potassium supplementation should begin when the potassium level is on the low side of normal rather than waiting until it is below normal, the reasoning being that early potassium supplementation may delay the progress of CRF. Cats in renal failure are unable to prevent excessive potassium loss and the body will extract potassium from tissue to maintain blood levels, thereby masking the actual potassium deficiency as measured by a blood test. ALWAYS consult your vet when supplementing potassium, whether your cat is in the early, middle or end-stage of CRF. The Dental Connection It is a good idea to have a mouth, teeth, and gum examination done during each annual examination. Just as in people, removal of tartar, teeth cleaning, etc. can be beneficial in keeping a cat healthy. The bacteria present in the mouth resulting from dental problems can certainly contribute to CRF. The relationship between the kidneys and blood pressure is complex. The kidneys play a crucial role in regulating blood pressure. The kidneys are also subject to damage from high blood pressure. Further, high blood pressure, by forcing the nephrons to work at above their normal capacity, can mask CRF for a while. The increased pressure causes the nephrons to deteriorate more rapidly, thus accelerating the course of CRF. Treatment for Hyperthyroidism Hyperthyroidism is one of the most common diseases of cats, particularly middle-aged and senior cats. Hyperthyroidism increases the blood flow to the kidneys and may mask symptoms of CRF. Recent studies indicate that a significant percentage of cats who were treated for hyperthyroidism (whether the treatment was surgical, radiological, or a life-long prescription for Tapazole) showed symptoms of CRF. These treatments reduce the thyroid hormone in the cat's system. Among other things, this reduces the blood flow to the kidneys. CRF that had previously been masked becomes apparent. Sub-clinical kidney failure can become clinical and even healthy kidneys can undergo some deterioration. It is crucial to monitor kidney function on a regular basis in cats who are being treated, or who have been treated for hyperthyroidism.
There is no cure for CRF but the condition may be managed for a time. The cornerstone of CRF management is to control the amount of waste products that are sent through the kidneys. Since the remaining nephrons are limited in their ability to process waste, the idea is to reduce the amount of waste to a level that the nephrons can accommodate. This is done through a combination of diet, medication, and hydration therapy (diuresis). Prognosis
CRF is a terminal disease. The only questions are how long and how well the patient will live until the end. With proper treatment, the cat may have from months to years of relatively high-quality life. As the cat's caregiver(s), it is up to you to determine when the quality of life has decreased to a point at which prolonging life no longer has value.
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