Download Feline Renal Insufficiency - Lockridge Animal Hospital

Recommendations for Cats with Kidney Insufficiency / Failure
Not many years ago, we did not recognize cats with kidney disease until they
were thin, anemic and very ill. Now that we do routine senior blood profiling, we can
and do recognize chronic kidney disease much earlier, giving us the opportunity to
intervene earlier and benefit animals in terms of both quality and quantity of life. Cats
that are managed early and well can live for years with chronic kidney disease.
This information brochure is designed to educate the owner of a cat with kidney
disease about the recommendations we may make for their pet’s future care. Not
everything listed here may be warranted for your pet. All recommendations are tailored
to the individual based on the stage of kidney failure which would be determined by
clinical symptoms, laboratory testing and other modalities described below. Your
veterinarian can discuss each of these recommendations in greater detail with you as they
become needed.
We generally make a diagnosis of kidney failure by performing a thorough
physical exam and through laboratory testing of blood and urine. The BUN (blood urea
nitrogen), creatinine and urine specific gravity are of particular concern. We also want to
rule out other complicating diseases such as hyperthyroidism, which is so common in the
older feline patient. Once primary kidney disease is recognized, we would proceed
depending on its stage. Some cats are in need of hospitalization to correct severe fluid,
electrolyte, and nutritional derangements. Other cats are found to be in very early kidney
failure, which we sometimes refer to as kidney insufficiency. They may have few, if any
symptoms. These cats are excellent candidates to benefit from early supportive care and
close monitoring.
1.) Blood and Urine Profiling with Urine Culture
Most animals have had this done to make the diagnosis. We follow values
in the blood and urine over time to determine if the disease is stable or progressing and
we use this to formulate our treatment and decide whether we should alter our treatment
plan. A urine culture is done initially to rule out kidney infection. We find a fair
number of senior pets can have urinary tract infections without any symptoms. Many
cats with pyelonephritis (kidney infection) can respond well to long term antibiotics.
2.) Blood Pressure
We check all cats for high blood pressure because up to 60% of all cats
with kidney disease will develop hypertension. The kidney is the main organ involved in
blood pressure control so any damage to its structure may lead to alterations in blood
pressure. Primary kidney disease is the most common cause of hypertension in animals.
Hypertension can cause serious eye, neurologic and cardiac related problems as well as
hasten the progression of kidney disease. Hypertension can generally be well controlled
with oral medication.
3.) X-Rays or Ultrasound of the Abdomen
We use these imaging techniques to evaluate the size and shape of the
kidneys, helping us look for a kidney tumor. We can determine if kidney, ureteral, or
bladder stones are present. The ultrasound is a much more sensitive tool to evaluate the
structure of the kidneys and in some cases would be a better choice over x-rays.
4.) Diet Changes
The first thing to be said about diet change is that your cat must like the
change! Foods are often returnable if your cat snubs them but we tell all clients that the
number one priority is that they continue to eat well. There are a number of kidney diets
available and many cats do make the transition and enjoy them. Your doctor may not
make a diet change recommendation early on or may suggest a moderate change to
something like GD (Geriatric Diet). These kidney diets are formulated with higher
quality but lower quantity of protein thus decreasing the waste products of metabolism
that the kidneys need to process. Maybe even more importantly, they are low in
phosphorous. Phosphorous is commonly elevated in the later stages of kidney disease
and can adversely influence the progression of kidney failure. Canned food is
encouraged to increase water intake. Sometimes water fountains or different types of
bowls around the home can also encourage water intake.
5.) Subcutaneous Fluid Administration
Cats with kidney disease become dehydrated over time even though they
often are drinking much more. This is because the kidneys have lost their ability to
concentrate the urine and therefore allow excessive fluid to be lost out through the urine.
Clients often notice an increase in urine output because the body is not conserving water
as it should be. Fluids are a gift to make the kitty feel better! Dehydration at a cellular
level can cause headaches, sluggishness, decreased appetite and constipation.
Subcutaneous fluids are sterile electrolyte solutions that are administered
under the skin and slowly absorbed directly into the system. Our technicians have
instructed many clients in this technique and they successfully administer the fluids at
home. Some clients prefer that we do this at the hospital and they will bring their cats 23 times weekly for a technician to administer the fluids. The volume and frequency,
again, would be determined individually and by the doctor in charge of your pet’s care.
Most clients become “experts” very quickly and do not find it stressful for their cat.
6.) Phosphate Binders
Phosphate binders are medications that are added to the food to bind
phosphorous so that it cannot be absorbed by the body. As mentioned previously, later in
kidney failure the kidneys fail to excrete phosphorous normally. This increase in
phosphorous plays a role in calcitriol formation and secondary hyperparathyroidism as
described below. It is important to keep phosphorous levels below 6 mg/dl to avoid its
injurious affects on the kidneys and the complications of high parathyroid hormone
levels. This can usually be accomplished with a kidney diet and/or the addition of a
tasteless phosphate binder powder to foods.
7.) Calcitriol
Calcitriol as the active form of Vitamin D is actually a hormone over
1,000 times as potent as natural or synthetic Vitamin D itself. Calcitriol is normally
manufactured in the body and the final step in it’s synthesis takes place in the kidneys.
Calcitriol helps your pet’s body absorb calcium and phosphorous from food and put it in
bones where it is stored. Parathyroid Hormone (PTH) works with calcitriol to release
calcium into the blood. This is vital. If your pet’s kidneys are failing and no longer
doing their job of making enough calcitriol, the parathyroid glands produce more PTH to
help normalize calcium and phosphorous in the blood. High levels of PTH directly
damage the kidney cells. By taking a carefully measured dose of calcitriol in capsule or
liquid form, we intend to keep the parathyroid glands from producing a toxic level of
PTH. The amount of calcitriol prescribed needs to be calculated specifically for your cat
by your veterinarian and can be prepared for you by a special compounding pharmacy. It
is desirable to administer calcitriol at low doses as early as possible in kidney failure to
avoid PTH excess from occurring in the first place. Blood calcium and phosphorous
monitoring is required at least twice yearly after initiation. The details of measuring
calcium and PTH should be discussed on an individual basis.
Nearly 2,000 pet owners and 250 veterinarians who used calcitriol were
surveyed recently. Over 80% of the owners reported that their pets seemed brighter and
more social and had better appetites when taking calcitriol. A study of cats showed that
29 cats that had PTH lowered lived over a year longer, on average, than did 21 cats which
did not have their PTH lowered.
8.) Other Ancillary Treatments
An “H2 Blocker” such as famotidine (Pepcid) might be prescribed to
decrease the potential for secondary gastric problems. The hormone gastrin is elevated in
kidney disease because it is not excreted properly into the urine. Gastrin promotes gastric
acid secretions and can lead to gastric bleeding and ulceration, which in turn could cause
anorexia and vomiting. “H2 Blockers” in essence block the receptors in the stomach that
produce acid. Gastrin has a reduced effect on the stomach cells when these receptors are
blocked.
Potassium supplementation may be necessary in some patients because
potassium is lost out through the kidneys and is not conserved properly. Also cats with a
decreased appetite may not be taking in enough potassium through their diet.
Vitamins may be used as a general supportive treatment and to aid in
secondary anemias. Blood cells are made in the bone marrow. Any chronic disease like
kidney disease can cause bone marrow suppression and anemia.
This list is not meant to be exhaustive. There may be different specific
recommendations for your pet. Again, every patient is an individual and their care should
be tailored to their specific needs and the desires of his or her owner. We are always here
to discuss options and answer questions.