Chronic kidney disease is a syndrome of kidney failure that’s common in ageing dogs and cats. Any disease processes that inflame the kidneys can contribute to chronic renal failure.
Unlike the liver, which is able to regenerate after illness, damaged kidney cells are not always replaced, often becoming scarred and useless. But because the kidneys usually cope until about 70% of the renal tissue is damaged, the disease is insidious and can be quite advanced when symptoms first appear.
As the kidneys become less able to function, the delicate balance of body water, electrolytes and waste products becomes disrupted. Excess water passes out in the urine, while toxic substances like urea build up in the bloodstream. The large amounts of water lost as urine causes dehydration and makes the dog thirsty.
This results in the first symptoms of kidney disease – excessive drinking and the passing of large volumes of urine. Despite frequent drinking, the pet can still become dehydrated.
Excess protein is also lost in the urine, causing the body to become malnourished and the urine to contain higher than normal levels of protein. The build-up of urea and other metabolic waste products in the bloodstream causes the dog to become depressed, lose its appetite, develop bad breath and mouth ulcers and, eventually, to vomit. Anaemia can also result from interference with red blood cell production (the kidneys play a crucial role in this process).
The symptoms described above are a good indicator of chronic renal disease but other disease processes need to be ruled out. For example, dogs with diabetes, thyroid disease and Cushing’s Disease also drink and urinate excessively, and urine can develop high levels of protein in cases of acute renal disease caused by toxins. Blood and urine testing – done in house at CVH – are important diagnostic tools that can help us pinpoint the cause of these symptoms.
Although most cases of degenerative kidney disease are incurable, careful medical management, avoidance of stress and good home nursing can give affected dogs a longer, high quality life.
The aims of treatment are to:
- maintain a good urine output
- reduce the work load of the kidneys and,
- replace those substances that are being lost in the urine.
The good news is that there are now medications available to help manage chronic renal disease. These act by increasing the blood flow to the kidneys, helping the body eliminate waste products and – as pets with chronic kidney disease often have high blood pressure – helping to maintain correct blood pressure.
Once the initial veterinary treatment has stabilised the patient (this may require intravenous fluids, for example), dietary management at home is very important. A kidney-supportive diet must be high in carbohydrates and fat, and low in protein.
The easiest and most effective way you can ensure your pet receives a diet nutritionally balanced for chronic renal disease is to feed a commercial kidney prescription diet. CVH stocks a high quality range of these excellent science diets.
Why do pets suffering from chronic kidney disease need a diet high in carbohydrates and fat, and low in protein?
Protein molecules are large and make the failing kidneys work too hard. But protein is essential, so choosing small quantities of high quality protein is safe. Red meat, in this situation, is regarded as a poor quality protein. Substitutes include cooked eggs and white meats such as chicken. Kilojoules to provide energy and maintain body weight are supplied by the carbohydrate and fat portion of the diet. Suitable foods include pasta and rice, but take care not to give large quantities of fatty foods – these can trigger pancreatitis.
We may also recommend supplementing the diet with water soluble vitamins B and C.
Large amounts of fresh water must always be available to ensure your pet doesn’t become dehydrated.
Dividing this low protein/high carbohydrate diet into 3-4 small meals each day reduces the workload of the kidneys (and if your pet has a poor appetite, smaller meals are more likely to be eaten).
Once your pet’s condition is stabilised, extra special care at home is very important – avoiding stress and providing a safe, comfortable and caring environment can make a real difference to your pet’s longevity and quality of life.