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Page 2 of 3 2. Filtering toxins
The body produces a lot of toxins during normal metabolism - these are
removed from the blood by the kidneys, and excreted in the urine. As
the kidneys fail, more of these toxins build up in the blood. Your cat
will start to feel listless, nauseas (noticeable by becoming a finicky
eater, eating less, or snubbing meals), and constipated. Weight loss,
especially muscle loss from protein malnutrition, makes this worse, as
nitrogen by-products build up. The toxins affect the brain (causing
confusion, depression, possibly headaches, central nausea and
vomiting), increase gastric acid secretion causing gastritis, vomiting
and stomach ulcers, and are the reason for the bad breath and oral
ulcers we often see. At high levels, they cause dementia, seizures, and
the whole terrible uremic syndrome.
The blood tests for kidney
disease actually measure the serum (blood) concentration of two toxins
- BUN (blood urea nitrogen) and CREATININE.
Body weight needs to be closely monitored.
Treatment centres around diluting these toxins and getting them out of
the body. The first step is rehydration, and maintaining daily
hydration - encouraging water intake, SQ fluids as needed.
In
human medicine, patients are placed on a low protein, low phosphorous
diet. Veterinarians extrapolated this concept to cats, but recent
studies are showing that protein restriction in our pet carnivores may
not be beneficial in early or mid-stage chronic renal disease. Protein
restriction is beneficial in end-stage uremic disease - but at this
point we are often more concerned with quality of life. Protein
malnutrition occurs very quickly in cats, especially if they wont eat
because of nausea. Renal diets may have less benefit in feline medicine
than originally thought. So initially, whatever kitty eats is fine, so
long as kitty eats and maintains body weight. This is a core concept!
Most cats survive many years with only SQ fluid support. Closer to
end-stage, dialysis becomes an important concept. It is rare for a cat
to undergo renal dialysis, and mostly veterinarians rely on the
second-best - an IV diuresis procedure which means your cat would be in
hospital on IV fluids for three to four days, every so often. Some cats
undergo a crisis such as concurrent kidney infection and do very well
after IV diuresis. Prognosis is only possible after the diuresis and we
can build an idea of how well those kidneys are coping.
Many
cats suffer from the renal gastritis. Very low levels of toxin build-up
can cause this. Start treating this early and do everything to prevent
this discomfort - because not eating can do more harm than the CRI to
the cat. Basis of treatment is SQ fluids, then drugs like famotidine
(Pepsid - 2.5 to 5 mg orally not more than twice daily) to prevent
gastric acid secretion, metoclopramide to prevent central nausea and
vomiting, odansetron and others. Sulcrate will coat and protect the
gastric lining. Bland nutritious diets help - plain boiled chicken on
"off" days, nutritionally balanced commercial diets for allergic cats
or diabetics with gastritis - avoid fibre diets or calorie restricted
senior diets or "prescription kidney diets" as these will make
constipation, dehydration and protein malnutrition worse.
3. Stimulating red blood cell production
The kidneys produce a hormone called erythropoitin which stimulates the
bone marrow to produce red blood cells. Red blood cells carry oxygen,
vital for energy metabolism and life support, to the tissues. Red blood
cells live about 100 days, and are constantly renewed. Without enough
red blood cells, your cat will feel weak and energyless. This is
noticeable as sleeping more, lethargy, less playful, sometimes
urinating or pooping outside of the box, antisocial behaviour, poor
grooming. They eat less (it is tiring to eat).
Haematocrit (Hct or PCV) is a measure of red blood cell amount.
At a Hct below 25%, we start supplementing erythropoitin.
The increase in red blood cells can significantly improve quality of life for the cat.
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