Question and Answer – Kidney Failure

Question of the week

Dear Doctor,

My cat, Socks has recently been diagnosed with kidney failure by my vet. Socks is sixteen years old and has been with the family since he was a kitten. I am devastated by this diagnosis. Does this mean that we will have to put Socks to sleep now? Our vet has spoken to us about treating Socks for the kidney failure, but I am not sure if I want to put him through that? Is treating him cruel and would I be keeping him alive for selfish reasons?

Jenny Considine
South Africa

Dear Jenny,

What is kidney failure and why do cats die from this? The kidneys filter poisons and waste products out of the body.They also make the urine concentrated to retain water in the body which helps to keep your cat well hydrated. If the kidneys fail, your cat will become dehydrated which will make him feel sluggish and tired and less likely to want to eat. Waste products and poisons will also build up in the body which will make him feel nauseous and unwilling to eat and he may even vomit. A cat that has chronic kidney failure will typically eat less and less over time, thus losing weight, drink a lot of water and even start to urinate in the house, He may start to vomit more often that he used to. So if left untreated. cat will die from dehydration and the build up of of poisons in their bodies. There are two types of kidney failure, acute – which comes on suddenly and in which the kidneys can literally shut down due to exposure for example to poisons and anti inflammatory drugs, and chronic, which is much more common and is usually seen as an old age change in cats.

Checking for dehydration by lifting the skin and seeing if it “tents”

The first thing you should know is that many cats with early uncomplicated kidney failure do well with treatment. Uncomplicated kidney failure means that there is not another disease in the body affecting the kidneys such as diabetes, hyperthyroidism, extreme anaemia, or cancer. How well a cat responds, how long he will live, and even whether you need to make the decision to put him to sleep all depend on the stage of kidney failure he is in. Kidney failure can be divided into four basic stages, with stage 1 being the earliest and stage 4 the most severe. The cats are divided into these stages by a simple blood test and a urine test, probably the same tests your veterinarian uses to diagnose your cat’s kidney failure in the first place. Cat’s in stage 1, 2 and even stage 3 often do very well with treatment and the treatment is not inhumane. Unfortunately cats in stage 4 do sometimes have to be put to sleep.  The cat that does not start to eat after it has been on a drip, or the cat that vomits continuously or has black loose stools, fetid breath with an inflammed mouth and gums, or oral ulcers, or the cat that does not become hydrated despite being put on a drip may need to be put to sleep for humane reasons.

Hermione is in stage 4 renal failure due to a cancer on her kidney

Treating cats with kidney failure first of all involves changing their diets. Most of the big names in pet food such as Hills, Royal Canin and Eukanuba make kidney diets for both cats and dogs. These diets differ from regular cat food in that the protein and phosphorus content is a lot lower, as diets high in phosphorus and protein such a fish and strong meats can damage the kidneys further and make the cat feel ill at the same time. They are also higher in carbohydrates and fats, as cats with kidney failure tend to lose weight. Because cats with kidney failure tend to be picky eaters they come in dry cubes, as well as tins and sachets with gravy to tempt your cat to eat them. It is important to avoid feeding strong meats with cats in kidney failure.If your cat does refuse to eat the commercially available foods there are recipes available on the internet that you can make up at home. The balance of minerals and vitamins in a commercially available diet is far better than a home cooked food however, so those are your first option. An example of a home cooked diet you can make up for your cat is shown at the bottom of the page. Most of the vitamins and minerals you need to add should be found at your local pharmacy or health food store.

Secondly, adding a small tablet to your cat’s routine every day. Cats have been found to do extremely well on a class of drugs known as ACE inhibitors. These drugs are commonly used for blood pressure problems in people. These drugs change the flow of blood through the kidneys, allowing more blood to be filtered per heartbeat. They also increase your cat’s appetite and help with weight gain. Cats do very well on these tablets and they help a lot. Cats with kidney failure will take these tablets for the rest of their lives.


Animals with Kidney failure often bruise easily

If your cat is in stage 2-4 kidney failure your vet will give you the option of fluid therapy. A simple infusion of 300 mls of saline under the skin on average about once a week will do wonders for your cat’s kidneys as it corrects the dehydration and also helps to flush out the poisons that build up in the body from kidney failure. Thus your cat feels better, is more lively and eats better. It takes about 10 minutes and your cat goes home with a lump of fluid under it’s skin which is absorbed over 6-8 hours. It’s amazing how much better they feel the next day. Some vets prefer to give an intravenous drip over a day in hospital. This has the same effect on the cat’s body as the fluids under the skin. Cats whose kidneys are worse will come more often than once a week and vice versa.

Some of the leading prescription diets available to treat kidney failure

Some cats develop an imbalance of calcium and phosphorus in the body. The prescription diets to help a lot to control this imbalance but in some cases it cannot be easily controlled and your vet may decide to put your pet on Calcitriol to aid absorption of calcium from the food he eats. Some cats also develop a potassium deficiency and this may have to be supplemented daily as low potassium in the body may lead to weakness. One out of ten cats with kidney failure unfortunately lose the ability to produce a hormone called Erythropoetin which is responsible for causing the bone marrow to produce red blood cells. These cats become very anaemic.  Erythropoetin injections are available and they will help greatly for a few months. Unfortunately most pets develop a resistance to the injections in their bodies and they stop working.

ACE inhibitors on the market for pets. Brand names may vary from country to country

Kidney transplants are available in some developed countries. Usually a donor matching cat is found at a local shelter, one of it’s kidneys are transplanted across and, the donor cat is adopted by the recipient’s family. This only really extends the lifespan of your cat about six months and your cat has to be on anti rejection medication the whole time. Your cat also has to be in early, for example, stage 1 kidney failure for it to be considered a good candidate for surgery.

Dr. Pitcairn’s Feline Diet for Kidney Problems

1 1/3 cups (2/3 pound) ground chicken, turkey or lean heart

4 cups cooked white rice

4 eggs

2 tablespoons cold-pressed safflower, soy or corn oil

1,500 milligrams calcium

1/8 teaspoon iodized salt

1/8 teaspoon potassium chloride (optional , for a saltier flavor)

1 teaspoon parsley, finely grated carrot or other vegetable (optional)

5,000 IU vitamin A

Taurine and other cat vitamins (about 5 days’ worth)

50 milligram level B complex (or 10 milligrams per day)

2,500 milligrams vitamin C (½ teaspoon sodium ascorbate)

Mix everything together in a large bowl. Serve raw if the cat will accept it. Otherwise, mix all but the vitamins together, bake about 20 minutes in a moderate oven and then wait until it cools to mix in the vitamins. Occasionally, substitute 1 to 3 teaspoons of liver for part of the meat.


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