Kidney failure in cats
Statistics show that more than 6% of cats examined by vets in the past few years – especially those aged 10 or older – were found to be suffering from chronic kidney disease (CKD), a leading cause of death in domestic cats. Studies show particular breeds seem predisposed to developing chronic kidney disease, including Persian, Siamese, Russian blue, Abyssinian and Burmese.
Aside from these genetic factors, there are several known triggers for kidney failure in cats, but often no precise cause is identified. Causes range from birth defects and congenital polycystic kidney disease, to chronic bacterial infection, high blood pressure, immune system disorders or exposure to toxins. In some cases, an acute kidney infection may damage the organs and lead to a chronic kidney problem, while the use of NSAIDs (non-steroidal anti-inflammatories) or antibiotics can also be a contributory factor.
Added to this are infectious diseases like FIV (feline immunodeficiency virus) or feline leukaemia. Even exposure to heavy metals such as lead may play its part. Kidneys help to regulate the many different blood factors: they control blood pressure by regulating sodium and keep blood sugars at healthy levels. By recovering water, they maintain its density and regulate the pH, thereby playing a vital role in the health and wellbeing of any cat.
The kidneys start to fail because there aren’t enough nephrons – microscopic tubes which filter and reabsorb fluids in the kidneys. Young healthy cats have more nephrons than they need, but these wear out in time and the remaining ones must work harder. As the nephrons become overwhelmed one-by-one the kidneys suffer damage. By the time two-thirds of the healthy nephrons are gone the kidneys can no longer conserve water and so more dilute urine is passed.
Treatments and Symptoms
When diagnosed, feline kidney disease is staged by severity, with stage 1 being the mildest form and stage 4 the most severe. Sadly, because the changes brought on by CKD usually take place over a very long period, by the time the symptoms become obvious, it may be too late for any effective treatment.
While chronic renal failure cannot be reversed or cured, it is possible to manage the factors which contribute to the damage and slow its progression further. One recommendation is a diet rich in quality protein and low in sodium and phosphorus which is present in larger quantities in commercially-available dried foods. Traditional therapies leaned on a low protein diet despite evidence that ageing cats need more protein, not less. But the operative word here is “quality”. The latest research shows that cats with renal failure thrive best on high-quality human-grade “wet” canned food or a fresh, balanced homemade diet. Unlimited access to fresh water should always be provided.
There is some evidence that it is the rise in the use of dry kibble foods for domestic cats over a lifetime increases kidney stress. Coupled with environmental toxins, often poor access to a quality water supply and a limited gene pool inevitably dooms today’s housecats to suffer chronic kidney disease.
For cats suffering severe effects, steps must be taken to deal with the effects of dehydration, anorexia, and vomiting, and to flush the accumulating waste products out of their system. In the most severe cases, your vet may administer intravenous fluid therapy. For less-affected cats an injection of fluids under the skin in the scruff of the neck between the shoulder blades is usually enough but may need to be repeated, even once the patient gets home.