PET HEALTH BULLETIN Winter 2013 1. Renal Disease in Cats and Dogs Kidney disease is one of the most common conditions affecting older pets, especially cats. Recent studies have shown that one in five cats above the age of fifteen has kidney disease. What do kidneys do? The kidneys are a vital organ in our pet’s body. They are responsible for many jobs all necessary for keeping our pet healthy. Kidneys regulate the internal water balance of the body to keep it hydrated. They also produce renin which helps maintain blood pressure. Kidneys are also responsible for excretion o f waste products. Kidneys produce erythropoietin which is necessary for producing red bloods cells. Older pets might also be on medication for other medical issues and the kidneys excrete some of these drugs out of their body. What causes kidney disease? Kidney disease can be due to many causes. In our older pets, it is often due to a degeneration of kidney tissue as a result of age. This disease usually progresses slowly. Other less common causes include exposure to certain toxin, severe bacterial infection, tumors or a flaw in the immune system. Occasionally, some animals can also be born with cysts within their kidneys which can affect the function of the kidneys. What are the signs of kidney disease? One of the first signs of kidney disease is frequent urination. As the kidneys are unable to help the body to retain water, animals with kidneys disease tend to urinate more. An excessive amount of drinking is then initiated in an attempt to replace loss of body water due to frequent urination. Diseased kidneys cannot effectively eliminate waste. Toxic chemicals such as urea and creatinine accumulates which cause nausea and can lead to vomiting. Weight loss is common as well due to poor appetite. Low erythropoietin levels affects regeneration of red blood cells and anemia results. Bad breath, mouth ulcers and blood in their feces are some of the other signs you might notice in advance kidney disease. If there is an underlying urinary tract infection, you might also notice some sign of straining and blood in the urine. How do we manage kidney disease? Although kidney disease is usually irreversible, it is manageable. The aim of the treatment is to preserve as many functions of the kidney and delay further progression of kidney disease. If well managed, we can greatly improve our pets quality of life. The treatment usually varies according to the severity of the disease. It can range from simple dietary modification, daily medication to hospitalization for several days in more advanced kidney disease cases. One of the cornerstones for managing kidney disease is dietary modification. Animals with kidney failure need to be on a diet that is relatively low in protein. This reduces the burden placed on the kidneys to excrete urea which is a waste product of protein. Feeding protein with high biological value is encouraged as it will be used by the body to build new tissue rather than be excreted. Examples of high biological value protein are those found in diary products (i.e. milk, cream, cheese etc.), eggs and organ meats (i.e. liver and kidney). Fish and lean meat such as chicken, rabbit or mince are best avoided. However, the best diets for animals with renal failure are veterinary prescription diets, including Hill/s prescription diet k/d and Royal Canine renal support. They are balanced and tailored to the special requirements of kidney failure patients. In addition to having the right amount and type of protein for renal failure cases, they contain a larger proportion of omega fatty acids which improve renal blood flow and fight renal inflammation. These commercial diets are also lower in phosphorous which help delay the progression of kidney disease. Lower sodium levels in these foods also help in managing blood pressure which prolongs its remaining kidney function. Vitamin B is also supplemented in this diet to replace the increase loss in the urine. Prescription diet contains higher levels of soluble fiber which helps lower the blood urea level by limiting ammonia adsorption from the bowel. When dietary modification is not enough, your pet may have to start taking daily medication. Often this will be a once a day tablet called Fortekor .Fortekor stops production of an enzyme that can lead to harmful effects on kidneys. It dilates blood vessels and so reduces the pressure in the kidneys which in turn reduces the amount of damage done to the kidneys. In severe cases, when your pet stops eating and starts vomiting, hospitalization is essential and fluid therapy is commenced for several days. This would help to correct the electrolyte imbalance and reduce the level or urea and creatinine in the blood. Hypertension (increase blood pressure) secondary to renal disease needs to be addressed to prevent blindness or stroke. Norvasc , a medication may be prescribed to lower the blood pressure in certain cases. Mirtazapine and Cryoheptadine are oral tablets that reduces nausea and help stimulates appetite. Low potassium levels in the blood can also be eliminated with the use of oral supplementation. If your pet is already on a renal diet and the blood phosphorous levels is still high, there are phosphate binders that can be taken to reduced phosphate in the diet. Frequent monitoring is essential to monitor the progress of kidney disease. We recommend that they be seen every 6 months for a blood test to measure the level of blood urea, creatinine, potassium, and sodium and phosphorous. Blood pressure should also be checked at each visit. It also provides your vet with an opportunity to asses hydration of your pet at each visit. Monitoring muscle mass and hydration is also essential. Kidney disease is irreversible and progressive but we can manage the condition with moderate dietary changes and the use of medication, as required. This allows our older pets to live a longer and better quality of life. Clinic news We would like to welcome Joanne Sattler, an aspiring Cert 4 vet nurse to join our team.