Chronic Kidney Failure
Chronic renal failure is the term used to describe the progressive loss of kidney function seen in older cats. The failure is a result of irreparable damage to the kidney, the cause of which is often not known. This damage reduces the ability of the kidneys to perform their important roles in maintaining normal body function. The kidney are responsible for filtering blood to remove toxins that build up as a result of the body’s metabolism, and controlling the body’s water and electrolyte balances. In this process urine is produced to excrete toxins and excess water, and urine can also be concentrated to retain water and prevent dehydration. As the kidney’s function declines the ability to concentrate urine is lost, and the cat will drink more to compensate, but will quite often be in a dehydrated condition. Loss of control of electrolyte balance can lead to a low potassium which can cause weakness and loss of appetite. A build up of toxins in the blood will result in nausea, vomiting, ulceration in the mouth and sometimes gastrointestinal tract.
The kidneys are also responsible for controlling blood pressure and red blood cell production, as a consequence anaemia and high blood pressure are often seen with kidney disease.
Chronic renal failure is one of the commonest conditions in the older cat. It can affect cats at any age but is common in middle to older age cats. The disease progression varies between individuals, some cats can lead a good quality of life for years as their kidney function deteriorates slowly, others sadly deteriorate more rapidly and euthanasia becomes necessary. Appropriate treatment and support can help to improve quality of life and prolong life as it can help to slow the disease process.
The symptoms of chronic renal failure often appear quite slowly. Symptoms most commonly reported are; drinking more water and producing more urine. Weight loss, vomiting and a decreased appetite are also often noted. A matted coat, bad breath, ulcers in the mouth, weakness and lethargy may also be noticed.
If your cat is displaying any of these symptoms we recommend an appointment with your vet to enable a clinical examination and history to be taken. Diagnosis is made from taking blood tests and urine samples.
Sadly there is no cure for kidney failure but treatments are available to try to slow the progression of renal disease and to improve and maintain quality of life.
The most important component of treatment is use of a special veterinary prescription kidney diet. These diets have controlled levels of protein and phosphate, this can have a protective effect on the kidneys by reducing their work load and slowing deterioration. The veterinary diets are carefully formulated to ensure that all nutritional requirements are met, and whilst protein is limited to a safe level, it is important that protein is not too low as this would result in weight loss.
Other treatments are aimed at controlling the side-effects and symptoms of chronic renal failure.
Dehydration is frequently present and in severe cases the cat may benefit from a stay in hospital on a drip. Fluids can also be delivered by subcutaneous injection.
Access to water is very important. Water intake can be increased by using wet kidney foods, and by placing multiple water bowls around the house. Cats particularly like running water, talk to us about getting a water fountain to help your cat drink more.
Often cats with chronic renal failure will have a raised blood pressure (hypertension). This can cause further deterioration of the kidney function with potential for leakage of protein into urine, and also have a detrimental effect on the heart and small blood vessels. Bleeding at the back of eye is a common side- effect of hypertension and can cause blindness. Blood pressure can be easily measured in cats and is an important part of monitoring a cat with chronic renal failure. Treatments that help lower blood pressure include medications like fortekor and istin.
Potassium will be monitored on blood tests and supplementation may be necessary. Phosphate will also be monitored, kidney diets help to control phosphate but additional help may be necessary in the form of phosphate binders.
Anaemia can also be present and will also be monitored on blood tests, use of anabolic steroid injections can help to stabilise the anaemia. These injections are often combined with Vitamin B12, a vitamin that is often low because it is excreted in urine. These injections can act as ‘pick me ups’ and they can be repeated every 3- 4 weeks.