Kidney failure, more common in older cats than young ones, seldom results in a shut down all at once, so a kidney problem can become a chronic, or, long-standing cat health problem. In that case, the kidney's tissues gradually deteriorate, until there is not enough functional tissue left to do the job.
The kidneys' job is to filter impurities out of the blood. So the individual usually dies when those toxins become overwhelming.
Fortunately, kidneys can maintain normal, or nearly normal, function for a long time - until only a tiny fraction of the kidney remains. However, this makes it easy to miss the signs of disease until it's too late. Add to that a cat's ability to keep a stiff upper lip through some of the most debilitating conditions and their reluctance to show pain, and you have a formula for tragedy.
Since cats seldom admit to feeling poorly, you have to be extra vigilant to even notice most cat health problems. Watch eating patterns, drinking habits, sleep cycles, personality changes, and litter box routines. These all can provide clues to your cat's health. With chronic renal failure (CRF) it is especially important to watch these things.
The disease typically progresses slowly, but it can run a more rapid course, too. It depends on why the kidneys are failing and how well the "patient" is supported.
Causes can include certain diseases of the kidneys, such as pyelonephritis, amyloidosis and chronic obstructive uropathy in older cats, or it can be caused by congenital defects or tumors in younger ones.
What to watch for:
In the early stages, the cat will typically be very thirsty and drink a lot, will urinate often and a lot, and there may be occasional vomiting. As the disease progresses, there will be loss of appetite, ulcers in the mouth, more vomiting, and diarrhea. In the terminal stage, there is severe dehydration, even more vomiting, convulsions, and sometimes they will go into a coma at this time, and death ensues. It is important to differentiate this from diabetes, as the symptoms are similar. Sadly, by the time any symptoms show up at all, it is likely the kidneys have already lost about 70% function.
What to do:
While there is no cure, there are things you can do to make your kitty more comfortable as the disease progresses.
* Provide lots of fresh water daily.
* Low protein diet. (There are commercial foods available that meet these requirements. Or, you can feed a high quality protein, such as egg or liver, in small amounts daily. Consult with a veterinarian who is familiar with CRF.)
* Low salt diet for cats that develop high blood pressure.
* Administer a medicated gel that contains aluminum hydroxide to control phosphate levels. (Cautionary notes: see med notes)
* Medicate with cimetidine to control stomach acidity.
* Supplements high in B-vitamins can help compensate for urinary losses.
* Steroids such as oxymethalone or nandrolone may help cats that are anemic.
* IV therapy may be needed for cats with uremia (waste products in the blood) in the final stages.
Remember to make dietary changes slowly as changes made too rapidly can make the condition worse.
More information here: The Problem Cat