Kidney failure is very common in cats, between 20% and 50% over the age of 15 will suffer to some degree. Unfortunately, it is often missed until it becomes advanced because the early symptoms are subtle and our feline friends are very good at hiding illness. However, the sooner it is caught the better
In most cases the cause for the kidney’s failing is unknown, it is just a gradual dying off of the tissue, particularly in elderly cats. If younger animals are diagnosed with the problem then can be a more obvious cause but it doesn’t often change the treatment plan.
The kidneys are the filtering organs for the blood. They remove all the waste products and toxins, sending them out in the urine. When they start to malfunction they become less efficient, these by-products stay in the body and, as they are effectively poisons, make the animal feel unwell and mildly nauseous. They are often mildly dehydrated, so it is not unlike a permanent hangover.
Feeling sick understandably means affected cats have poor appetites and to survive the body has to break down its own tissue. Unfortunately, this creates very high levels of toxic metabolites, which stay in the blood stream, make the cat feel worse, so they eat even less and so the vicious cycle continues. The toxins themselves also directly damage the kidneys, further exacerbating the problem.
The big challenge with kidney disease is that the organs will have been dying long before any signs, either in the cat or on tests, are seen. Animals have far more kidney tissue than they need and it is only when approximately 70% is destroyed, is there any sign of the problem. Also, the organ is non-regenerative, so once it’s gone, it’s gone.
I describe it to my clients that it’s like a snowball rolling down a hill. Once we discover the problem it has already picked up significant momentum. We cannot stop it but we can slow it down. This is why it is so important to catch it as early as possible.
The early signs of renal disease are vague; slow, gradual weight loss which is often missed; being quiet in themselves and sleeping more, which can easily be written off as ‘just old age’ and occasional vomiting. Unless vets and owners are actively looking for problems; for example regularly weighing older cats or doing simple urine tests or blood analysis, it is easy to miss until it is more advanced and the pet is obviously poorly.
The mainstay of treatment for kidney failure is a change in diet. Prescription foods for renal disease are designed to treat several aspects of the problem at once and studies have shown that cats who eat them, will live longer.
These diets are easily digestible, so produce fewer toxic left-overs than normal cat food; they are supplemented with ingredients which help the remaining kidney tissue to function as best it can and contain vitamins and minerals that affected cats are often deficient in.
Although these foods are very palatable and with time and patience most cats will accept them, some elderly felines are very stuck in their ways! A good appetite is vital in renal patients so for them, and for some more badly affected pets, there are supplements that can be added to their usual food which have similar, positive effects.
Another treatment which I use regularly is the administration of fluid under the skin. Although renal patients drink copious amounts, they are chronically dehydrated. Subcutaneous fluids really help to combat this, helping them feel better and therefore eat better.
Also, kidney disease is often both a cause and consequence of high blood pressure, another very common problem in older cats. Again a vicious cycle is in action; the higher the blood pressure, the poorer the kidney function and poor kidney function very often leads to high blood pressure. All feline renal patients should have their blood pressure regularly checked and treated if it is raised.
Chronic renal failure is one of the most commonly diagnosed illnesses in older cats and all owners should be on the lookout for the early symptoms. My one tip is to weigh your cats regularly, as often the first sign of this, and many other diseases, is insidious weight loss.
If you are concerned about your pets, have a chat to your vet. Kidney problems are easily identified with simple, non-invasive urine and blood tests and the sooner it is caught the better! Affected cats, with the correct treatment and care, can live for years after diagnosis!
Cat Henstridge BVSc MRCVS – Read more of her blogs at www.catthevet.com
If you have any worries about your pet, please make an appointment with your vet, or try our Symptom Guide.