Kidney failure (or renal failure) is a common ailment in cats that can be fatal. Many owners don't notice symptoms of kidney failure in their cat until the cat's kidney function is reduced well below normal capacity. It's imperative for cat owners to recognise the early symptoms associated with kidney failure.
As kidney function begins to fail, cats often drink more water. Kidneys normally filter out toxins and salts, as the kidneys begin to fail, more toxins remain in the cat's bloodstream, making the cat more thirsty. Your cat may drink more frequently throughout the day and stay at its water bowl for very long periods of time. Take your cat to the veterinarian if you observe this behaviour. The vet will run blood work to find out if there is a problem.
With reduced kidney function, built-up toxins in the cat's bloodstream may be expelled through normal breathing, which is noticeable as bad breath. You may confuse this with your cat simply needing a dental cleaning, especially if your cat's teeth are dirty. Take the cat to the veterinarian to let him diagnose the reason for the bad breath.
Vomiting is another sign of kidney failure in cats. When toxin levels and impurities build up and irritate the body, a cat may feel sick and nauseous. As the levels become high enough, the cat is likely to vomit, much in the same manner as when you drink or eat too much of something and it sickens you.
Cats experiencing kidney failure often urinate more frequently than normal. This is because they are usually drinking more water to try and flush out the toxins building up in their body. As a result of the increased water intake, they will urinate many more times per day.