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Renial Failure in Cats
By: Dawn M. Fiedorczyk


Renal failure is the second most prevalent cause of death in felines throughout the United States. This ailment is most commonly diagnosed in cats around the age of seven, but the possibility of incidence increases with age (Messonnier, 2002). While the average life expectancy after diagnosis is approximately two to three years, the duration of survival is dependent on detection, treatment and care (Burkholder, 2000).

It is often a frightening and disheartening experience to find out that your beloved cat has been silently suffering with kidney failure and that your remaining days together are numbered. Understanding some of the structures and functions of the kidneys may help owners to identify and relate signs and symptoms to the possible presence of kidney failure and possibly help to prolong the life of their cat.

Figure 1

Structure and Function

The structure of the kidneys in cats is similar to those of most other mammals. The only difference seems to lie in the color of these organs. While most kidneys are dark, reddish-brown in color, the cat's kidneys are yellowish-brown. Cats have two bean-shaped kidneys located along both sides of the spine, beneath the first few lumbar vertebrae, as seen in Figure 1 (McBride, 1996; Max's House, 1998). This general area is often tender when the kidneys are compromised during renal failure.

Figure 2

Two of the most important organs in the urogenital system, the kidneys are composed of an renal cortex and an renal medulla both enclosed in a renal capsule, as seen in Figure 2 (Bachman, 2003). In terms of renal failure, the nephrons are the most important structures in the kidneys. There are approximately one million of these nephrons in each of the kidneys (Randall, et.all, 2002). All of the nephrons are not used simultaneously; therefore there is a reserved supply of nephrons available. Unfortunately, by the time renal failure is diagnosed, usually sixty to seventy percent of the nephrons have been destroyed (Waltham, 1999).

These minute nephrons are self-contained structures found within the medulla and are responsible for filtration, reabsorbtion, and excretion. Each nephron filters blood received by the kidney through the renal artery (figure 2), reabsorbs important minerals and nutrients, eliminates the waste products into a urine-collecting duct and returns the purified blood to the vena cava through the renal vein (figure 2) (McBride, 1996; Vanderschaegen, 2002). Because the kidneys are the most significant structures in purification of the blood, they receive the equivalence of the total volume of blood in the body, or approximately twenty percent of the cardiac output of blood from the renal artery, every four to five minutes. After leaving the vena cava, the blood returns to the liver where it can be further purified, while the urine is removed from the kidney by way of the ureter (Randall, et. all, 2002).

Figure 3

During the production of urine, the kidneys are responsible for removing the products of metabolism and other waste substances from the body. As illustrated in Figure 3, the kidneys produce the urine and then transport the urine through the ureters to the urinary bladder. The urinary bladder then stores the urine until enough is collected and the urine is eliminated from the body through the urethra (Waltham, 1999).

Some substances filtered out by the kidneys through the urine include nitrogen, minerals, salts, excess glucose, toxic substances, and water from metabolism and ingestion (Randal, et. all, 2002). The glomerulus filtration rate (GFR) is the rate at which the blood is filtered through the kidneys to remove these waste substances. If the rate is too slow, waste products remain in the body for extended periods and can have toxic effects on the kidneys and the rest of the body. However, if the GFR is too rapid, beneficial components of the blood, such as protein, do not have the time to be reabsorbed in the body and are removed through urine. An irregular GFR lets wastes build up and can cause nutritional deficits or other problems (Vanderschaegen, 2002). Obvious signs of nutritional deficits are a decrease in coat quality, hair loss, weight loss, vomiting, and diarrhea.

Beyond the production of urine, the kidneys play important roles in several other processes and synthesis throughout the body. The kidneys are also involved with the regulation of electrolytes, maintenance of hydration, regulation of blood pressure, controlling pH, biosynthesis of several important chemicals, formation of red blood cells and activation of vitamin-D3.

Sodium and potassium are two of the most critical electrolytes regulated by the kidneys. The kidneys produce and release a hormone called angiotensin that regulates the fluid levels of sodium in the blood stream. The potassium level is dependent upon this sodium level to remain in equilibrium. Together the sodium and potassium functions in the body to maintain blood pressure and proper functioning of the heart (Long Beach Animal Hospital, 2002). A disruption in this sodium potassium balance often results in high blood pressure and various heart and muscle abnormalities. Signs of electrolyte imbalance may include lethargy, sudden blindness and muscle pain and stiffness (University of Edinburgh, 2002).

In addition to maintaining electrolyte balance, the kidneys cooperate with the brain to maintain fluid levels in the body. If the fluid levels in the body are too low, the body is termed dehydrated. By measuring the blood volume that passes through the brain, the brain recognizes this dehydration and releases an anti-diuretic hormone, known as vasopressin (Long Beach Animal Hospital, 2002; Waltham, 1999). Vasopressin signals the kidneys to reduce the amount of water they excrete into the urine and to increase thirst. In effect, the urine becomes more concentrated and is eliminated from the body less frequently when vasopressin is released. As the body is re-hydrated, the brain secretes decreasing amounts of vasopressin. This decrease in vasopressin concentration allows the kidneys to resume elimination of larger amounts of water in the urine and increases the frequency of urination. This entire cyclic process of dehydration and hydration is disrupted in cats that are experiencing signs consistent with discrepancies in hydration, such as greatly increased or decreased urination, excessive drinking, and tacky, dry gums.

Maintenance of the production of and concentration of urine, sodium and potassium levels and the GFR function together to regulate blood pressure. They do this by controlling fluid levels in the body. This fluid level then determines the amount of serum (liquid component) in the blood. The volume of blood the heart needs to pump, the rate at which the heart can move the blood through the body and the potassium assisting in the functioning of the heart all work together to regulate blood pressure (Waltham, 1999). Any disruption in this process can result in fluctuations in blood pressure. Cats in renal failure often have high blood pressure that if left too high for too long can lead to lethargy and sudden blindness.

The kidneys also regulate the process that controls the pH of the blood stream. The kidneys regulate the acid-base balance within the body through the selective secretion of hydrogen ions and the selective secretion and absorption of bicarbonate ions (Long Beach Animal Hospital, 2002). Renal dysfunction often results in the inability to secrete ammonia compounds from the body and absorb bicarbonate ions into the body. This condition is also known as metabolic acidosis and can cause bone demineralization, inhibited protein synthesis, and expansion of the heart. A disruption in acid base balance, caused by the kidneys, is often associated with anorexia, lethargy, vomiting, and weightless (University of Edinburgh, 2002).

One of the less recognized responsibilities of the kidneys is biosynthesis of several important chemicals needed throughout the body. Renin, prostaglandins and antihypertensive lipids, erythropoietin and vitamin-D3 are all substances that rely on the kidneys for production and/or secretion (Waltham, 1999).

Renin, prostaglandins, and antihypertensive lipids are all manufactured and secreted by the kidneys maintain blood pressure. When the pressure blood pressure within the kidney is too low, the kidney releases renin to initiate a complex process that raises the blood pressure within the kidney and throughout the entire circulatory system. To balance the effects of renin, the kidney also produces and secretes antihypertensive lipids and prostaglandins to lower blood pressure. Inadequacies in this system, resulting from compromised kidneys, can cause dangerous fluctuations in blood pressure (Waltham, 1999).

Erythropoietin, a hormone that stimulates bone marrow to produce red blood cells, is biosynthesized and released by the kidneys. A disruption in this synthesis of erythropoietin can cause a decrease in the number of red blood cells in the blood (anemia) (Long Beach Animal Hospital, 2002). This decrease occurs because red blood cells are constantly being destroyed within the body and must be replenished. Clinical signs of anemia, resulting from malfunction of the kidneys ability to regulate red blood cell production, include lethargy, respiratory distress, and pale gums.

The gradual decrease in calcium concentration, caused by natural body functions, initiates the parathyroid hormone to search for more calcium in the body. Because of this natural decrease of calcium in the blood, the kidneys supply and then convert vitamin-D3 to its active calcium containing form, calcitrol. The kidney's supply of vitamin-D3 causes the absorption of more calcium from the gut and intestines (Long Beach Animal Hospital, 2002; Waltham, 1999). Increased absorption and plasma blood concentration of calcium halts the parathyroid hormone from drawing calcium from other sites in the body. Without the kidneys' role in this process, the parathyroid hormone obtains calcium from any location where it is available. The cats with impaired kidney function often are affected by a decrease in overall bone density. Decrease in bone density often causes a stiff gait, frailty, and weakness.

Acute and Chronic Renal Failure

STAGES OF KIDNEY DISEASE
Loss of Renal Reserve - Early signs of PU/PD
PU= polyuria (increased urination)
PD= polydipsia (increased drinking)
Renal Insufficiency - Early warning signs, such as increased thirst, may begin to appear
Renal Failure (Azotemia) - Kidneys cannot eliminate waste efficiently, causing signs of illness
Advanced Kidney Failure (Uremia) - Severe signs of illness appear; eventually, collapse and death result
Figure 4

A cat is considered to be in varying degrees of chronic or acute renal failure when their kidneys are unable to perform properly. Examining the four general stages of acute/chronic renal failure in Figure 4 highlights the progression of the disease (Hills, 2002). This diagram vividly shows the degradation of the diseased kidney through four stages of failure. The first through third stages depict a relatively healthy kidneys gradual decline and give some brief information about the progression of signs as failure progresses. By the last stage, when 90% or more of the nephrons are destroyed the smaller necrotic (dead) kidney can directly cause death from the build up of toxins. Both acute and chronic renal failure share many similar signs and symptoms and are both potentially fatal. However, acute and chronic renal failures differ in their causes, treatments, and long-term prognosis. Any degree of renal failure must be treated immediately and aggressively because of its serious nature. Unfortunately, by the time pet owners recognize something is wrong with their animal; the kidney failure has already greatly progressed.

Doctors use the term acute renal failure (ARF) to label patients whose kidneys have acquired the sudden inability to regulate water and solute balance. This form of renal failure can be more broadly defined to be a rapid deterioration of renal function (Labato, 2001). Acute renal failure often has a sudden onset and can be reversed if treated quickly and aggressively. However, the sudden onset of renal failure is often misinterpreted as another condition or missed altogether and leads to the progression of chronic renal failure. Causes of ARF are divided amongst pre-renal, renal, and post-renal categories. Pre-renal causes are factors that precede fluid entering the kidneys. The pre-renal form often results from any condition, such as shock or dehydration, decreases the body's ability to transport fluids to the kidneys. Post-renal causes are factors that occur after the wastes and/or urine exit the kidneys. The post-renal form often results from conditions that obstruct or tear the urinary tract that inhibit the wastes and urine from efficiently being removed from the body in a timely manner.

With pre and post-renal failure forms considered, the most common causes of acute renal failure are identified as ischemia (cellular damage from the loss of blood and oxygen supply) and nephrotoxicty (toxicity caused by substances poisonous to the kidneys). After diagnosing acute renal failure, treatment is dependent upon determining the cause of and the stage of ARF (Labato, 2001). ARF is commonly divided into the induction, maintenance, and recovery phases. Figure 4 depicts the highlights and kidney conditions of these four phases.

In the initial induction phase, the kidneys may exhibit injury from ischemia, nephrotoxins or infectious agents. Nephrotoxins may include various natural or synthetic chemical agents from various household products and/or plants. Some common household products classified as nephrotoxins includes, but are not limited to antifreeze, pesticides, herbicides, solvents, aspirin, anti-inflammatories and some antibiotics, such as paramomycin (Long Beach Animal Hospital, 2002; Gookin, 1999). The leaves and/or flowers of plants, such as Asiatic hybrid lilies, arrow grass, wild cherry, elderberry, oleander, Japanese yew, and the pits of apples, peaches and apricots, are all also considered nephrotoxins (Oehme, 1977; Cannon, et.al., 2000). Some infectious agents may include the bacteria that cause pyometria (an infection in the uterus) and the bacteria that cause septic shock (Labato, 2001). Vascular disruption from these causative agents and injury to cells result in the overall decrease in red blood cell formation, decreased GFR and decreased excretion of urea and creatinine, a condition know as azotemia.

In the next phase, the maintenance phase, anuria, the inability to produce urine, is common. At this point ARF commonly progresses as damage to both the tubular cell's ability to reabsorb sodium and the individual nephrons' GFR lead to due to the inability to regulate fluid flow. Anuria is usually a result of the death of the tubular cells and/or obstruction of the flow of urine from cellular swelling. This maintenance phase usually lasts for approximately 7 to 21 days before possible progression to the recovery phase (Labato, 2001).

If the kidneys are not too badly damaged, ARF will enter the recovery phase. During this final phase, filtering of the body occurs through dieresis, the artificial increase in the amount of fluids in the body. Dieresis is made possible through the introduction of oral, subcutaneous (SQ) (under the skin) or intravenous (IV) introduction of fluid into the body. Resulting from the dieresis, polyuria, and a general improvement in renal function usually occurs over a period of approximately one to two months (Labato, 2001). Over this period, nephrons in the kidneys attempt to self-repair and compensate for those nephrons that are not salvageable. Continuing problems with the kidneys or a progression to chronic renal failure is a possibility if too many of the nephrons are replaced by scar tissue, from the inflammation present.

Unlike acute renal failure, chronic renal failure is a progressive and irreversible loss of renal function over a relatively long period of time, generally a period of more than two weeks in duration (Hughes et.all, 2002) (Waltham, 1999). Chronic renal failure has become increasingly common in older felines represents the end stage of one or a combination of diseases affecting the kidneys. Chronic renal failure, unlike acute renal failure, is not reversible. The outlook for patients in chronic renal failure is grim because by the time this form of the disease is diagnosed 65-75% of the renal tissue has already been destroyed (Duval, 2002).

Chronic renal failure has a number of possible causes and most researchers and clinicians have conflicting views of these causative agents and/or factors. However, not all cats that experience or are exposed to the possible causes develop chronic renal failure (Long Beach Animal Hospital, 2002). Some of the generally agreed upon causes of chronic renal failure include advanced ARF, high blood pressure, congenital disorders, glomerulonephritis (abnormalities in the glomerulus), cancer (commonly lymphosarcoma and adenocarcinoma) and a variety of other diseases, such as diabetes (Long Beach Animal Hospital, 2002). Whatever the cause, immediate detection and treatment are always vital in slowing the progression of the disease. The survival rate of cats in chronic renal failure varies and is usually dependent upon cause and the amount of damage that is done before the disease is discovered.

Detection

Increased urination, increased thirst, weight loss, anorexia, lethargy (inactivity), ulceration and discoloration of the mucous membranes of the gums and tongue, vomiting, diarrhea and neurological signs, such as seizure activity or inability to walk, are all signs that are characteristic of renal failure (Waltham, 1999). Signs may initially be vague, but progress according to the severity and cause of the disease. Early detection of renal disease is an important step in providing adequate supportive care and slowing the gradual or rapid deterioration of health consistent with renal disease. Unfortunately, by the time pet owners have recognized some obvious signs, the kidney failure has already greatly progressed. Unless the disease was detected through clinical testing, the majority of the nephrons have usually been destroyed before signs or symptoms are seen.

Diabetes and hyperthyroidism are just two of the many diseases that have similar symptoms to renal failure (Duval, 2002). After recognizing possible signs and symptoms of renal failure, a veterinarian must perform clinical testing to make an accurate diagnosis. Blood work and urinalysis are two of the easiest, quickest, and most common methods in diagnosing renal failure. A hematology blood work panel, testing the quality and numbers of the various cells of and in the blood, may be helpful in indicating anemia and dehydration resulting from a kidney disorder. A biochemistry blood work panel is also very important in measuring the blood urea nitrogen (BUN) (a nitrogen-containing byproduct of protein metabolism), plasma creatinine (a byproduct of muscle exertion) and phosphorous (acquired from dietary intake) levels (Waltham, 1999; Columbia Animal Hospital, 2002).

BUN, creatinine and phosphorus are all products processed by the kidneys that are classified as uremic toxins. Elevated levels may indicate kidney malfunction. In a healthy cat the BUN is generally between 14 and 36 mg per deciliter of blood, the creatinine is generally between 0.6 and 2.4 mg per deciliter of blood and the phosphorous is usually between 2.4 and 8.2 miliequivalents per deciliter of blood (Long Beach Animal Hospital, 2002; Duval, 2002). These values may seem tedious at first, but when dealing with a patient in renal failure it is vital to keep track of these numbers in comparison to normal parameters. As kidney failure progresses, the BUN, creatinine and phosphorus levels will gradually increase indicating the need for more supportive care and hydration. After kidney failure is diagnosed, it is recommended that blood values be reassessed every three to six months to check for and protect against further health complications initiated by the failing kidneys (Long Beach Animal Hospital, 2002).

Veterinarians also use urinalysis to detect and accurately diagnose kidney disease. Kidney problems are indicated when the specific gravity and components of the urine are abnormal. The specific gravity measures the concentration of urine. The specific gravity of a cat's urine usually rises above 1.045 preceding primary renal failure and falls below 1.035 during primary renal failure (Waltham, 1999). Comparing the specific gravity to BUN can determine if the BUN is elevated from dehydration or from kidney dysfunction. A high BUN and a low specific gravity indicate kidney dysfunction, while a high BUN and high specific gravity usually indicate dehydration (Long Beach Animal Hospital, 2002).

The sediment, or the solid particles dissolved in urine, is also examined to detect for the presence of protein, blood, crystals, tubular casts, bacteria, abnormal cells, and other foreign particles or substances in the urine (Waltham, 1999). Collectively the detection and measurement of all of these components detect renal disease as well as other primary or secondary problems. Specifically, protein, blood, and bacteria are sediments in urine that should be filtered out by the kidneys and their presence may indicate kidney dysfunction.

Figure 5

Besides the common use of blood work and urinalysis, other diagnostic tests may be used to accurately and efficiently diagnose the presence of renal failure and its possible causes. X-rays, ultrasounds and biopsies are important tests used by some veterinarians to both help diagnose, treat, and possibly determine the origin of renal dysfunction (Columbia Animal Hospital, 2002). X-rays and, more accurately, ultrasounds are used to determine the size, shape, and changes in the anatomy of the kidneys. An x-ray of normal feline kidneys can be seen in Figure 5 (Long Beach Animal Hospital, 2002). Ultrasounds further enable the inspection of the internal anatomy of the kidneys and show a more precise dimensional measurements and shape. In a healthy cat normal kidney measurements are approximately 2.3 cm by 3.6 cm., as seen in Figure 6 (Long Beach Animal Hospital, 2002).

Figure 6

Ultrasounds can also plot the exact location for biopsy that can be used to examine the presence, characteristics, quality and number of cells in the kidneys. Biopsies are gradually becoming more widely used in determining whether the damage to the kidneys is reversible or irreversible (Swashima, et.all, 1999). During a biopsy a small amount of tissue from the kidney is collected analyzed (Drost, et.all, 1999).

Current research has advanced the prospects for earlier detection of kidney problems and thus prevention of renal failure. A new urine test for dogs has offered a means of earlier detection by screening for albumin; a protein that begins to leak from the glomerulus of the kidneys preceding decreased renal function. This test has been proven to detect albumin when the kidneys are still functioning at nearly one hundred percent. Detection this early could alert pet owners and veterinarians to take immediate action before too much of the kidneys are damaged. Soon this test may be perfected and available for cats (Heska Corp., 2003).

Medications

Selected medications provide some of the most important and effective supportive care for felines in renal failure. Numerous medicines are available and are commonly used for the identified secondary complications. While none of them are curative, many of these medications successfully allow for comfortable management of the disease and may even prolong the life of the patient. Administering medication to a cat however is not always the easiest task. Sometimes flavored, highly palatable formulas are available to entice a cat to cooperate, however just like humans, a sick animal usually does not willing take their medicine. Figure 7 may provide a useful depiction on how to "pill" a cat ( Max's House, 1998).

Figure 7

Amphogel tablets and Phos-Ex are two drugs commonly used to bind to and eliminate excess phosphorous within the body (Kingstowne Cat Clinic, 1999). These medications help to diminish the increased amount of phosphorus that the compromised kidneys cannot remove on their own. While these medications decrease phosphorous levels, other medications are necessary to regulate potassium and calcium levels. Tumil K and potassium gluconate are two drugs used to supplement potassium, while calcitrol is often used to supplement additional calcium.

Pepcid AC, Reglan and Periactin are three drugs often used to treat gastrointestinal problems in cats in renal failure. Pepcid AC is an over the counter medication that decreases stomach acid production and helps prevent and/or alleviate the discomfort of gastrointestinal ulceration and bleeding, commonly caused by an elevated BUN. Drugs such as Tagament, Zantac, carafate and cytotec are also sometimes favored for ulcer prevention and alleviation (Duval, 2002). Veterinarians prescribe, Reglan, a medication effectively used to help stop the patient from vomiting. Periactin, and sometimes Valium, are prescribed as appetite stimulants to artificially stimulate the hunger response (Kingstowne Cat Clinic, 1999). These stimulants are important because as a cat's appetite diminishes they receive less of the proteins and minerals necessary for every day survival. When diet does not adequately provide these needed components, the body will obtain proteins and minerals from anywhere and by any means necessary. This often involves the breakdown of the body's own tissues and bone.

Medicinal therapy usually begins when a cat's blood pressure is consistently over 180mm (Long Beach Animal Hospital, 2002). Norvasc is one of the first drugs chosen and the one still most commonly used to treat hypertensive cats. Enalapril is another blood pressure medication that is sometimes used. Once these medications are prescribed a veterinarian must perform weekly blood pressure monitoring until the blood pressure is stabilized and then repeat the monitoring every two to three months thereafter. While the cat is under blood pressure treatment owners should closely watch for weakness, associated with a blood pressure that is dangerously low. If weakness occurs, a veterinarian must be notified promptly.

If the red blood cell count is too low, a blood transfusion may first be required before drug therapy is initiated because there must be enough red blood cells initially available while the body works to make more. Winstrol and Epogen are two drugs commonly used to stimulate red blood cell production. Winstrol is an anabolic steroid usually used when anemia is mild. However, if the anemia is more sever, Epogen, a synthetic form of human erythropoietin, is available to naturally stimulate the bone marrow to produce red blood cells. Epogen can be used for only 30 to 90 days because approximately 30% of cats gradually develop antibodies to this drug. This resistance is seen because this drug was initially designed for human use and developed in human compatible media. Due to its incompatibility with cat blood types, Epogen is reserved for severely anemic cats and if rejected other therapies must be used.

Treatment

Subcutaneous (under the skin) fluid therapy is currently one of the most important and effective treatments for cats in renal failure. During this therapy, commercial, enriched fluid solutions are placed under the cat's skin. Lactated ringers solution is a commercially prepared solution that is commonly supplemented with B vitamins and potassium chloride (Kingstowne Cat Clinic, 1999). The B vitamins are added because they are water-soluble and are frequently lost in the excess urination. Potassium chloride is also often added to regulate the potassium balance interrupted by the failing kidneys. Once the fluid line is connected to the bag of fluids, a sterile needle, at the end of the fluid line, is inserted in the soft, pliable skin in the cats back. To reduce the stress on the cat, owners can perform this process in the comfort of their home with some practice. This process takes a minimal amount of time, is virtually painless, provides supplemental hydration and nutrients, and can help flush toxins from the renal patient.

Dietary therapy is another easy, effective method to manage kidney failure. The main object of this therapy usually is to return blood phosphate levels to normal parameters. On average, regulating phosphate levels through dietary management can add approximately two years to a renal failure cat's life (Feline Advisory Bureau, 2003). Decreasing the amount of protein in the cat's diet has also been found to help because the kidneys are responsible for breaking down proteins. A decreased amount of protein lessens their workload. However, decreasing protein in a cat's diet must be done cautiously because diets with low protein levels are often less palatable and the cat may refuse to eat. With concurring nutritional deficiencies and anorexia often present, offering a bad-tasting diet can make cats eat less and suffer further body wasting. Feeding a diet that is rich in calories, not derived from protein sources, provides much needed energy, and even taste while avoiding the problems caused by increased protein content (Burkholder, 2000). Hills K/D® Science Diet is a specially formulated food for patients in renal failure. While veterinarians commonly recommend this diet, there are other diets designed for cats with renal dysfunction.

Cats with kidney failure are often anemic because the kidneys do not stimulate red blood cell production. While synthetic erythropoietin treatment and the use of Winstrol are helpful in this situation, sometimes the blood count is just too low to support the cat's needs. The packed cell volume (PCV) is a measurement of the percentage of red blood cells in whole blood. A normal PCV for a cat is between 24 and 45 (Veterinary Technician, 2002). When the PCV falls below 15, a blood transfusion is sometimes necessary. Whole blood is transfused and in emergencies does not have to be cross-matched with the cat. However, if subsequent transfusions are needed, cross matching is necessary to prevent rejection of the foreign blood.

Hemodialysis and kidney transplantation are two more invasive, clinical treatments that have offered new methods to prolong the lifespan of patients in kidney failure. Hemodialysis is currently being used on patients that are not responding to conventional medicinal therapy. During hemodialysis, a patient's blood circulates to a complex chamber outside of the body. This external, specially designed chamber filters and purifies the blood while also correcting electrolyte imbalance. This procedure is technically demanding, expensive, and time consuming, but with increased research and awareness, can become a feasible therapeutic treatment for renal failure in the future (Elliot, 2000).

Kidney transplantation is another relatively new method of treatment for cats in renal failure that performed in a few veterinary schools throughout the U.S. (Aldin, et.all, 2001). The success rate for this operation is approximately 75% with 25% of recipients dying from rejection, infection, cancer, or diabetes. However, the oldest known survivor is still well twelve years after his transplant. Preoperatively, comprehensive blood work and urinalysis, x-rays, an echocardiogram, an abdominal ultrasound, blood typing and blood pressure monitoring are some of the tests routinely on the recipient and donor cats (Bernsteen, 2003). Cats eligible for transplantation must be in the early stages of acute or chronic renal failure and must otherwise be healthy (Bernsteen, et.all, 2000). Transplantation is rarely performed on fractious (nasty) cats because the aftercare is rigorous and lengthy and involves frequent medicating and veterinarian rechecks. Cyclosporin is currently the veterinarians' drug of choice in preventing organ rejection and usually costs sixty dollars per month. Altogether, the price for surgery and aftercare can exceed ten thousand dollars (Bernsteen, 2003). The cat's owner must also agree to adopt and provide a lifelong home for the donor cat. Due to its relatively new place in renal failure treatment, excessive cost and limited margin to ensure effectiveness, this surgery has not yet gained much popularity.

Holistic therapy provides another option for treatment. Various herbal treatments have been developed and used in the treatment of renal failure. Acupuncture is also used to help stimulate appetite and improve blood flow to the kidneys (Scanlon, 2002). However, due to the controversial nature of holistic therapy no information was readily available as to the outcomes of its use.

Prevention

Because a cure for chronic kidney failure has not yet been discovered, it is beneficial to enact preventative measures to help ward off the possibilities of developing any form of kidney disease. While it is not possible to eliminate the risks of acquiring the disease, it is beneficial to minimize the risk in any manner available. Using a diet that is low in protein, phosphorous and salt reduces the strain on the kidneys. A diet that is more plentiful in carbohydrates and fat will decrease the likelihood of kidney failure because these two energy-producing components are excreted through routes other than through the kidneys. A plentiful supply of fresh, clean water is also essential and helps to promote drinking and ensure proper hydration (Green Oaks North Pet Hospital, 2003).

A close relationship with a cat can also aid in renal disease prevention. Owners should remove potentially toxic agents from all areas of their home that cats frequently visit. Noticing the normal behavior patterns of your cat can help you to recognize when they are not feeling well and allow you to contact your veterinarian. Yearly checkups and routine vaccinations are equally helpful not only to prevent unnecessary disease but also to have your cat thoroughly examined by a professional. As your cat begins to age, routine blood work also helps to monitor any significant changes that may indicate potential problems. Overall, when used together, all of these preventative measures may be useful in securing a long healthy life of your feline companion.

Conclusion

The possibilities of a cat developing renal failure are high so owners should understand the diagnosis of the disease to prolong their cat's life. Recognizing signs and symptoms early can help to identify and treat the disease and thus increase the likelihood of success. Due to its terminal nature and the inevitable progressive decline in health, supportive medications and treatments are the only possibilities for relief and should be sought after and used. While research is ongoing due to the large number of cats affected by this condition, preventative methods remain the most important means of protecting your cat's health and comfort.

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