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Kidney Disease in Dogs |
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Kidney Disease in Dogs
Kidney Failure in the Dog and Cat
Chronic Renal Failure
Kidney Failure-Where to begin
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| NORMAL KIDNEY
PHYSIOLOGY |
CAUSES OF KIDNEY FAILURE |
DIAGNOSIS OF KIDNEY FAILURE |
TREATMENT OF KIDNEY FAILURE |
The kidneys receive about 20
percent of the heart's blood output and play a vital role in
keeping the dog or cat in normal metabolic balance. The glomerular
blood vessels have a large endothelial surface which allows for the
active and passive transport of many chemicals into and out of the
kidneys.
Capsule". Most of the fluid that passes into the Loop of Henle in the
cortex is reabsorbed in the medulla back into the blood.| Click
on a heading to jump to that topic... |
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| Hereditary/Congenital Abnormalities |
Trauma |
Toxins: External and Internal |
| Bacterial Infections |
Blockage of Urine Outflow |
Medications |
| Fungal Infections Such as Blastomycosis |
Cancer |
Autoimmune Diseases |
Generally arising from gradual spread of external bacterial organisms near
the external urinary orifices, the bacteria multiply and invade the
urethra, then into the bladder (causing what is termed CYSTITIS), and
occasionally further retrograde up the ureters and eventually into the
kidneys.
kidneys involves kidney stones or bladder stones or urethral
obstruction. These mineral concretions (usually called struvite
uroliths) can form in the urine of the kidney pelvis or bladder and
remain for long periods of time without causing serious trouble.
Easily contaminated with bacteria, however, urinary calculi are a major
nidus of bacterial proliferation and will cause physical irritation to
the kidney or bladder tissues. These irritated tissues become
thickened, scarred and prone to chronic infection. Under certain
circumstances a kidney stone can become lodged in the ureter leading
away from the kidney toward the bladder and obstruct urine flow from
the kidney. If the situation persists for days the increased back
pressure on the affected kidney will permanently damage kidney function
and cause what is termed hydronephrosis...
a kidney swollen under pressure with backed up urine. Surely this
is a life threatening situation. Generally this will occur in a
single kidney and if only one kidney is damaged and the opposite kidney
is normal, bodily waste removal needs can be met by the single
remaining kidney. Take a look at a kidney removal surgery
due to an obstructed ureter.
. It
doesn't take much of this sweet tasting liquid to
prompt crystals to form in the delicate tubules of the kidney's
filtration systems. Massive doses of Vitamin D can be nephrotoxic
(poisonous to the kidneys), rodent poison such as D-Con can allow
hemorrhaging into
the kidneys, the Easter Lily plant can be toxic if ingested and heavy
metal
toxicity such as from lead, mercury, cadmium, and arsenic all pose a
very
real threat to kidney tissue. Other renal toxins include thallium and
turpentine. There is evidence that raisins/grapes can be
nephrotoxic to dogs.
In
nearly all cases of kidney failure the kidneys are unable to
concentrate urine. That means the
Urine Specific
Gravity measurement (SpG) that indicates how concentrated the
urine is compared to distilled water (SpG = 1.00) will display a dilute
reading... actually, very close to distilled
water. Since the action of conserving water while allowing
undesirable
metabolites and toxins to remain in the urine is the job of the tubules
in the kidneys, whenever the tubules are damaged water conservation
is less efficient; therefore more water flows through the tubules
unresorbed
and washes away in the now dilute urine. Most cases of kidney
failure
display a SpG of about 1.008 to 1.012. Generally, a normal dog's
urine SpG will be 1.020 to 1.040; generally a cat's urine SpG will be
about
1.025 to 1.050. If a water deprivation test is done, where the
animal
has no access to water for 18 hours, the urine specific gravity goes
up...
the urine becomes more concentrated. (Generally, if kidney
failure
is suspected a water deprivation test is not done because it will
render
the patient even more toxic.)
When renal function is diminished,
many, many toxic chemicals
build up in the patient's
body. Think of the situation
as you would if there were no smoke stack on a factory and
all those burned gasses and chemicals stayed within the walls of the
factory. That's just what happens when kidney failure is
present. In many patients, slow and progressive loss of filtering
tubules creates a situation where these toxins very gradually build up;
in other acute kidney diseases (such as anti-freeze poisoning) the
sudden and massive damage creates immediate toxin buildup within the
body. Many dogs and cats become accustomed to very gradual toxin
buildup as slowly progressive kidney disease moves toward the critical
limit where there are not enough healthy nephrons to eliminate waste
products. Eventually, outward signs of kidney disease becomes
evident.
Treating kidney failure is one of the most
consistently discouraging aspects of veterinary medical practice.
The difficulty stems from the fact that once a dog or cat has lost 75%
of total renal function, the ability to remove metabolic waste products
is outweighed by the buildup of those toxins. The animal is
simply not able to keep
up with the "housecleaning" and as a result gradually becomes
increasingly
more toxic. Body chemistry swings more and more acidic, important
chemicals and nutrients are lost from the body and the animal comes
gradually
closer and closer to a fatal uremic poisoning. In some cases,
gradual
kidney tissue loss can be present for years before the patient becomes
critical and actual "renal failure" is diagnosed.
Research done
decades ago indicated that rodent kidneys were
adversely affected by diets high in protein... and misguided
researchers
extrapolated that data to apply to the canine. There is no evidence
that feeding dogs and cats diets rich in or "high" in protein actually
causes kidney damage or disease. Some day this myth will be
finally
be put to rest. In fact, there is ample research and well
documented
studies that prove that dogs and cats thrive on diets with levels of
protein
consistent with a meat-eater's (carnivore) natural prey
selection.
Read more about protein in dog and cat diets here. | Kidney
Disease Case History |
Watch for Chronic Renal Failure as
Pet Matures |
Chronic
Kidney Disease |
Kidney
Failure in Dogs |