Issue Description Renal failure or kidney failure occurs when
the kidneys aren't able to function properly. They are made up of
hundreds of thousands of nephrons, which filter out wastes from the
blood stream in the form of urine. In addition to this, the kidneys
are also responsible for maintaining water and electrolyte balances,
and producing some hormones such as erythropoietin, which stimulates
red blood cell production. Other Names Renal Failure
Causes Presumably, the term "chronic renal failure"
suggests that the kidneys have quit working and are, therefore, not
making urine. However, by definition, renal failure is the inability
of the kidneys to remove waste products from the blood. This
definition can occasionally create confusion because some will equate
renal failure with failure to make urine. Renal failure is NOT the
inability to make urine. Ironically, most dogs in kidney failure are
actually producing large quantities of urine, but the body's wastes
are not being effectively eliminated.
There are two types of renal failure: acute and chronic.
Acute renal failure occurs very quickly as a result of lost function.
It can be caused by toxins such as antifreeze, or many poisonous
plants. It can also be caused by low blood pressure, a decrease in
blood volume, a lack of blood supply to the kidneys, or a urinary
blockage. Acute renal failure is potentially reversible, but can
become chronic if left untreated.
Chronic renal failure is
most commonly seen in older cats, but does also occur in dogs. Because
signs of renal failure don't usually become apparent until 65-70% of
kidney function is lost, chronic renal failure has been going on for
months or even years. There is no cure for chronic renal failure, and
the goal is to slow progression and improve the pet's quality of life.
Symptoms Report any changes in your dog's eating,
drinking, and elimination habits to your veterinarian. Such changes
may alert your veterinarian to the possibility of kidney disease - or
help your practitioner adjust treatment if therapy has already begun.
With kidney disease, your dog becomes less alert, loses its appetite,
and may vomit. Take your dog to your veterinarian if it shows any of
the following signs that sometimes (but not always) point to kidney
1. Increased thirst and urine volume
2. Weight loss
3. Weakness and exercise intolerance
4. Tendency to bleed or bruise easily
1. Dehydration (To test for this, gently pull the skin away from your
dog's middle. If the skin does not immediately spring back, the dog
may be dehydrated.)
2. Stiff-legged gait and arched back (a sign of painful kidneys)
3. Little or no urine production.
Diagnosis Renal failure is diagnosed by symptoms and
laboratory testing. Measuring urine's specific gravity helps the
doctor determine if the kidneys are properly concentrating urine.
Blood tests are also run looking at BUN and Creatnine levels, which
are two products excreted by the kidneys. Elevated levels in the
blood, also called azotemia indicate kidneys aren't functioning
properly. A low packed red cell volume indicates anemia.
Treatment Treatment of kidney failure in dogs occurs in
two phases. The first phase is to "restart" the kidneys. Large
quantities of intravenous fluids are given to "flush out" the kidneys.
This flushing process, called diuresis, helps to stimulate the kidney
cells to function again. If enough functional kidney cells remain,
they may be able to adequately meet the body's needs for waste
removal. Fluid therapy includes replacement of various electrolytes,
especially potassium. Other important aspects of initial treatment
include proper nutrition and drugs to control vomiting and diarrhea.
There are three possible outcomes from the first phase of treatment of
kidney failure in dogs:
1. The kidneys will resume functioning and continue to function for a
few weeks to a few years.
2. The kidneys will resume functioning during treatment but fail again
as soon as treatment stops.
3. Kidney function will not return. Unfortunately, there are no
reliable tests that will predict the outcome.
The second phase of treatment in dogs is to keep the kidneys
functioning as long as possible. This is accomplished with one or more
of the following, depending on the situation:
A special diet. The ideal diet is low in protein, low in
phosphorus, and not acidified. This type of diet helps to keep the
blood tests as close to normal as possible, which usually makes your
dog feel better. Also, once kidney disease is advanced, a decreased
protein diet will decrease the workload on the kidneys.
A phosphate binder. Phosphorous is removed from the body by
filtering through the kidneys. Once the filtration process is
impaired, phosphorous begins to accumulate in the blood. This also
contributes to lethargy and poor appetite. Certain drugs will bind
excess phosphates in the intestinal tract so they are not absorbed,
resulting in lower blood levels of phosphorus.
Fluids given at home. Once your dog is stabilized, fluids can be
given under the skin (subcutaneously). This serves to continually
"restart" the kidneys as their function begins to fail again. This is
done once daily to once weekly, depending on the degree of kidney
failure. Although this might not sound like something you can do, you
will be surprised at how easily the technique can be learned and how
well most dogs will tolerate it.
A drug to regulate the parathyroid gland and calcium levels.
Calcium and phosphorus must remain at about a 2:1 ratio in the blood.
The increase in blood phosphorus level, as mentioned above, stimulates
the parathyroid gland to increase the blood calcium level by removing
it from bones. This can be helpful for the sake of the normalizing
calcium:phosphorus ratio, but it can make the bones brittle and easily
broken. Calcitriol can be used to reduce the function of the
parathyroid gland and to increase calcium absorption from the
intestinal tract. This is recommended if there is evidence of abnormal
function of the parathyroid gland.
A drug to stimulate the bone marrow to produce new red blood
cells. The kidneys produce erythropoietin, a hormone that stimulates
the bone marrow to make red blood cells. Therefore, many dogs in
kidney failure have a low red blood cell count, anemia. Epogen (or
Procrit), synthetic forms of erythropoietin, will correct the anemia
in most dogs. Unfortunately for some dogs, the drug cannot be used
long term because the immune system recognizes the drug as "foreign"
and will make antibodies (immune proteins) against it. This is
recommended if there is persistent anemia present.
Prognosis To determine the prognosis of kidney disease,
blood and urine tests are performed frequently during treatment to
evaluate how well the kidneys are responding. It's a good sign if test
results swing back toward normal within the first 48 to 72 hours of
Initial test results can be remarkably similar for
both forms of kidney failure. The diagnostic challenge is to determine
whether the dog has acute or chronic kidney failure. Making the
distinction between chronic and acute failure is crucial because the
prognosis and duration of treatment for the two types of kidney
disease are different (although some treatment procedures may be