Download Chronic Renal (Kidney) Failure

Chronic Renal (Kidney) Failure
What is chronic renal failure?
Let’s first discuss exactly what the kidneys do. Kidneys are responsible for filtering out waste,
toxins, and excess water from the bloodstream and eliminating it by producing urine. Toxins
and waste occur from the normal breakdown of active tissues such as muscle tissue, and from
food. This waste is then released into the blood stream where it is sent to the kidneys to be
filtered out of the blood along with excess fluid and eventually removed from the body in
concentrated urine. In chronic renal failure the kidneys become less efficient at performing this
task. This means that kidneys need more fluid to eliminate the same amount of waste. To do
this the kidneys remove more fluid out of the bloodstream. This fluid is needed by other body
systems which now do not have enough so the body tells the patient to drink more. This is why
patients with chronic kidney failure seem to drink and urinate more than normal. Eventually
the pet simply cannot drink enough fluids and the toxin levels in the blood stream begin to rise.
This creates symptoms such as weight loss, loss of appetite, nausea, and listlessness.
Diagnosis
Diagnosing renal failure is always made through a combination of laboratory testing of both
urine and blood. Some of these tests will need to be repeated on a regular basis to monitor a
particular pet’s response to treatment. In the following section we will discuss what the
different tests are and why we do them.
Urinalysis
This is an examination of the urine. The most important aspects of this for a dog in renal failure
or renal disease are specific gravity, protein content, and indications of infection. Specific
gravity is the evaluation of how concentrated the urine is. In kidneys that are working properly
specific gravity usually greater than 1.020 with 1.040 and higher being very well concentrated.
Any urine with a specific gravity less than 1.020 in considered dilute. What this means is that
the kidneys are using an increased amount of fluid to expel waste. Dilute urine can also occur as
a result of any disease process that is causing the pet to drink more fluid than usual.
The amount of protein in the urine is important because protein is something that the kidneys
should be sending out to recirculate in the body instead of eliminating it in the urine. Protein in
the urine can be an indication that the kidneys are not doing that job as well or it can indicate
some other kind of inflammation along the urinary tract.
Urinary tract infections can be a little harder on pets with kidney failure and kidney disease.
During a urinalysis a microscopic examination can reveal if white blood cells, red blood cells, or
bacteria are present. This is because the infection can affect the entire urinary tract including
the bladder and the kidneys. Infection in kidneys that are already not working properly can
cause even more increases in toxin levels. It can also take longer to get control of a kidney
infection in these patients and they may need to be on antibiotics for a longer period of time.
Blood Tests
Initial diagnosis is usually made after a full panel of blood work that can help to evaluate the
health of many of the major organ systems with in the body. The following tests that will be
discussed are the values that are most indicative of renal function and many of these will need
to be monitored throughout treatment.
Creatinine (CREA)
Creatinine is a product of the normal occurring breakdown of muscle tissue. It is released into
the blood stream and filtered out by the kidneys. Large amounts of this in the blood stream
indicate that the kidneys are not filtering properly. A healthy patient has a creatinine level
under 2.0. When first diagnosed with renal failure creatinine can reach 29.0 prior to treatment.
Good values for a patient in renal failure are under 4.5.
Blood Urea Nitrogen (BUN)
Blood Urea Nitrogen is a byproduct from the metabolism of proteins from the liver that are
usually filtered and excreted by the kidneys. Healthy pets generally have a blood urea nitrogen
level under 31. Pets with previously undiagnosed renal failure can have values in excess of 300
however values of 60-80 are considered to be good for patients being treated for this condition.
It is important to note that results of this test can be increased by other factors such as
dehydration, liver function, and even diet so it is very important to look at these values along
with other kidney related tests.
Phosphorus (Phos)
Phosphorus is excreted during the normal lifecycle of all the cells in the body that is filtered by
the kidneys. High levels of phosphorus in the body can cause inflammation within the body and
even weaken bones. Normal levels of phosphorus are less than 6.0. Patients with renal failure
often have levels over 7.5.
Potassium
Failing kidneys often lose the ability to conserve potassium efficiently. Low potassium or
“hypokalemia” often causes weakness especially drooping of the head. For this reason
potassium supplements maybe needed for some patients with renal failure. Normal potassium
levels are between 3.4 and 5.6.
Complete Blood Count (CBC)/Packed Cell Volume (PCV)/Hematocrit
These are tests that help us know the amount of red blood cells circulating in the bloodstream.
The packed cell volume and hematocrit let us know the percentage of the blood that is made
up of the red blood cells while a CBC allows us to see the number of red blood cells as well as
the percentage. This is important because the hormone that encourages the production of red
blood cells is excreted by the kidneys. As kidney function declines so does the production of this
hormone. Without adequate production of red blood cells the pet becomes anemic. To
complicate things, patients in renal failure need extra fluids. The administration of these extra
fluids can worsen the anemia.
Blood Pressure
Blood pressure cannot be monitored through a blood test. Special equipment is needed to
measure blood pressure in pets. The reason this is important is because the kidneys also
produce a hormone that help to regulate blood pressure. Hypertension (high blood pressure)
often occurs alongside renal disease. This is especially important for cats with this condition.
Treatment Options
Treatment depends on the severity of the disease. Advanced cases may require 24-72 hours of
hospitalization on intravenous fluids in order to stabilize the toxin level. Blood levels are
checked several times during this period to see how effective this treatment is.
In less severe cases treatment begins with delivering fluids under the skin (subcutaneous). This
procedure can be done safely and effectively at home once you are properly trained. It sounds
scary at first but it is generally both easy to learn and well accepted by both cats and dogs.
Dialysis is available for our pets however it is usually very expensive and does require transfer
to a center that is set up to perform veterinary dialysis. The center closest for us in Kentucky
and Indiana is in Philadelphia, PA. For more information please inquire with your veterinarian.
Diet is another key that becomes very important in managing your pet after diagnosis. Most of
the prescription foods made for pets with this condition work to restrict protein and
phosphorus as well as other properties to promote metabolic health. The diet recommended
most in our clinic is Hill’s K/D Diet. It is available in both dry and canned varieties.
Phosphorus binders are also often used to reduce phosphorus levels. This is a medication that
helps by binding to the phosphorus in the gastrointestinal tract and then eliminating it when
the animal has a bowel movement. This can help to reduce the amount of phosphorus
circulating in the blood stream.
Calcitrol is a medication that represents activated vitamin D. Vitamin D is not a vitamin in the
usual way people think of vitamins in that it is actually a hormone. This hormone plays a very
important role in the calcium phosphorus balance and is beneficial in slowing down the
progression of the disease if it is started while phosphorus levels are still in normal range.
There are many benefits to this medication when it is used properly but it must be started early
in the disease process.
Medications to control blood pressure or to supplement potassium may also be needed.
Medications to help control nausea and acid production in the stomach are also often
prescribed for patients with kidney failure. For these medications it is best to discuss with your
veterinarian which ones would work best in your pet's situation.
You are not alone when it comes to dealing with chronic renal failure. There are many
resources on the web that can help with tips, information, and thoughts about the disease.
Resources for dog owners:
http://www.veterinarypartner.com/Content.plx?P=A&C=&A=2633&SourceID=42
Online mailing list http://pets.groups.yahoo.com/group/K9KIDNEYS/
Resources for cat owners:
www.felinecrf.org/
Online mailing list http://groups.yahoo.com/group/Feline-CRF-Support/