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Kidney Disease in Cats - Chronic Renal
Failure
By Jean Hofve, DVM
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Signs of Renal failure in cats. Increased
thirst is often the first symptom
Kidney disease, in the form of chronic
renal failure (CRF), is a common problem in older cats. I have seen kidney
failure in cats as young as 4 years, but far more frequently in much older
cats. The most noticeable symptom is an increase in water consumption and
urination ("drink-a-lot, pee-a-lot syndrome"). A blood test should be done
if you notice these symptoms, as there are several conditions that can
cause this. The increase in drinking and urinating in CRF is due to loss
of the kidney's ability to concentrate the urine. The kidneys have a very
large reserve capacity, and symptoms of kidney failure are not seen until
approximately 75% of kidney tissue is non-functional. In my experience,
kidney failure is the most common cause of death in older cats.
Causes of
Chronic Renal Failure
Recent research suggests a link between
vaccination for feline distemper and immune-mediated inflammation of the
kidneys, which is thought to be the cause of CRF. Annual boosters for
distemper are completely unnecessary. Be sure to discuss all recommended
vaccines with your veterinarian. A cat with kidney disease or kidney
failure should not be
vaccinated at all.
Long-term feeding of an all-dry-food
diet is also suspected as a factor in Chronic Renal Failure. Cats' kidneys are highly
efficient and adapted to life in the desert, where they would get most or
all of their water from eating their prey. Cats eating dry cat food take
in only half the water that cats on a canned or homemade diet get; this
chronic dehydration can cause stress on the kidneys over time. Dry diets
also predispose cats to lower urinary tract disease (FLUTD, LUTD, FUS,
crystals, stones, cystitis) because they force such a high degree of urine
concentration. Chronic or recurrent bladder disease may also be a factor
in the development of CRF.
Treatment of Chronic Renal Failure
Chronic kidney failure is
progressive and incurable. No conventional or alternative medical
treatment can reverse its course, since the disease involves the loss of
kidney cells and replacement by scar tissue. The rate of progression in
any individual cat probably cannot be slowed to any significant degree.
When the process is advanced, the kidneys become small and lumpy, and the
amount of functional tissue is greatly limited. The most significant
problems caused by the loss of function are build-up of blood toxins, and anemia. These can cause weight loss, lethargy, vomiting, loss of appetite,
weakness, and other signs of illness.
Some cats are able to maintain their body weight and live relatively
comfortable lives for months to years, while others succumb to the disease
more quickly. In conventional medicine, there are drugs that can minimize
anemia, and phosphate binders to prevent phosphorus precipitates from
further damaging the kidneys. However, these may not be palatable, and may
cause adverse reactions. They are also of little or no value unless the
cat is eating a restricted protein/low phosphorus diet exclusively. It may
also be important to supplement potassium in the food.
Diet for Kidney Failure in
Cats: The Protein Controversy
You may have heard that restricting
protein is recommended for cats in kidney failure. Although this has been
the "standard" treatment for decades, as far as cats are concerned, it has
always been--and remains--very controversial. According to experts at
Colorado State University's veterinary teaching hospital, restricted
protein does not prevent kidney failure in a healthy cat, and has
no effect on the ultimate progression of renal disease. Research
also shows that even very high protein diets do not make renal failure
worse in cats (although high protein does worsen the disease in dogs and
humans). (One pet food maker recently completed a study it claims shows
that its restricted-protein diet increases lifespan in CRF cats. However,
because the study has not yet been published, it is impossible to evaluate
the data, which is contradicted by other research.) The real culprit is
actually phosphorus, which meat contains in large amounts. Decreasing
phosphorus intake (by restricting protein) can help some cats feel better,
so it may be worth a try in a symptomatic cat.
However, some studies have suggested
that excessive restriction of protein may actually cause further damage to
the kidneys and other organs, because there is not enough protein for
normal body maintenance and repair. Experts
say that these diets are not
appropriate until the BUN (Blood Urea Nitrogen) is at least double what it
should be normally (about 60-80 mg/dl).
Furthermore, there is one big problem
with using the protein-restricted commercial diets: many cats don't like
them, and won't eat them. Obviously, it does little good to provide a
special diet if the cat is going to starve to death! Experts emphasize
that it is much more important to feed the cat what he likes and will eat,
and maintain weight and body condition, than to be overly concerned about
protein content. (Please note that if you add any other protein source to
the diet, it will completely negate any possible beneficial effect from
the low-phosphorus renal diet. It is useless to feed both a renal diet and
a normal protein food or meat-based treats at the same time.)
Let me say this again, because it is the
single most important thing to know about CRF: feed the cat anything she
will eat! IF THE CAT WON'T EAT IT, IT WON'T HELP THE CAT! Weight loss is
your cat's worst enemy in this disease; so let the cat eat what she wants!
Because water balance is so crucial, it
is best to feed a high-moisture diet to help keep the cat hydrated; do not
feed only dry food. Feeding mostly or only canned food, even though it is
high in phosphorus and protein, provides the moisture and calories that
these cats need, in a very palatable form that most cats will happily eat.
You can also get low-phosphorus renal diets in canned form. Dry cat food
causes dehydration even in healthy cats, and is not appropriate for CRF
cats (unless, of course, it's the only food he will eat!).
The best thing you can do is feed a
home-prepared diet; but only if the cat will eat it! If the cat has never
eaten homemade food, or does not have a hearty appetite, this is not a
good time to make this switch! There are several good books on home
cooking for animals, such as Dr. Pitcairn's Guide to Natural Health for
Dogs and Cats, by Richard Pitcairn, DVM, and Susan Pitcairn. (Rodale
Press. ISBN 075962432.) They discuss why a diet made from fresh, raw foods
is important, and provide recipes, including a special recipe specifically
designed for animals with kidney disease. Another excellent book is
Home-Prepared Dog and Cat Diets: the Healthful Alternative by Donald
R. Strombeck, DVM. (Iowa State University Press. ISBN 0813821495.) If you
choose to use Dr. Strombeck's recipes, I suggest substituting 1 capsule of
taurine (250 mg) for the canned clams, since clams do not contain enough
taurine for proper maintenance.
Special Nutrition for
Chronic Renal Failure
Several nutritional supplements may be
helpful for cats with kidney disease. Omega-3 fatty acids have been shown
to be beneficial in CRF. Antioxidants are also important. Both of these
are contained in the highly digestible algae,
Biosuperfood. A nutritional supplement called "Renafood" from Standard
Process, is a good renal detoxifier and helps to maximize kidney function
in cats. Give one or two a day. Most cats eat them readily if they are
crushed into the food. Call Standard Process at 1-800-558-8740 to find a
distributor in your area. Remember, though, that the basic diet is the
most important factor in your cat's health, and no supplement will make up
for poor quality nutrition. For more info on feeding, choosing a good
food, and switching to a better diet, see the many nutrition articles in
our
Library.
Supplemental Fluids
Your veterinarian can give your cat
subcutaneous fluids in the clinic, or teach you how to give them at home.
This is the least intrusive and most beneficial treatment you can give
your cat. Cats in chronic renal failure drink a lot of water, but they
cannot drink enough to compensate for the loss of water through the
kidneys. Subcutaneous fluids are an excellent way to help keep the toxins
flushed out of the bloodstream and make the cat feel much better. If the
cat is sick or not eating, it may be necessary to hospitalize it for a few
days for intravenous fluid therapy, followed by subcutaneous fluids at
home as needed. The recent development of a
semi-permanent "port" that can be inserted in the cat's skin has taken
much of the hassle out of this procedure; talk to your vet about having
this installed. It is best to have this procedure done by a veterinarian
who has lots of experience with these ports since there can be many
complications.
Holistic Veterinary Care
While no treatment can create new kidney
cells when scar tissue has already formed, homeopathy, herbs,
flower essences, or acupuncture may be
able to help your cat feel better and live a better quality of life.
This copyrighted article is reprinted with
permission courtesy of
Little Big Cat:
www.littlebigcat.com
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