Occasionally during the course of your dog’s life your veterinarian may request that blood work be done. This could be for any number of reasons including routine check-ups, because the dog needs to be temporarily sedated, or due to an unrelated ailment. Blood is extracted in the same manner as it for people when we have blood work done, and the sample is sent to a lab for analysis. Unfortunately, the actual results of the blood work can be confusing without prior training. One possible result that will be discussed here is when the blood work reveals elevated liver enzymes.
What your veterinarian tests for
If you examine your dog’s blood work yourself, you will see that the same types and levels of elements that you find in human blood work are present. Red blood cell counts, white blood cell counts, hemoglobin and differentials between blood elements are all accounted for. Understanding each and every interaction and possible diagnosis is beyond the scope of this article, but the discovery of elevated liver enzymes can have a number of possible inferences as discussed below.
General Function of the canine liver
First, the function of the canine liver is no different than our own in terms of purpose. As with humans, it is the job of the canine liver to metabolise protein, fat and carbohydrates; store vitamins and minerals, and aid in the digestion of food and detoxify wastes. All of these functions are performed through the bloodstream. Dr. Race Foster (D.V.M.) describes the critical importance of the liver: “Twenty percent of the blood pumped by each and every beat of the heart goes through the liver. Additionally, the first tissue to get a chance at the nutrients absorbed by the intestines and stomach is the liver. Every blood vessel leaving the gastrointestinal tract goes directly into the liver. The liver takes from, adds to, and changes in some way, all of the blood that passes through its mass.”
By testing the blood of dogs, veterinarians can get a very accurate reading on the current state of the liver although the causes of why the liver is in that state can be varied.
Reading the results of a blood test
The component areas on canine blood work that indicate liver function are ALP (Alkaline phosphatase), ALB (Albumin), GGT (Gamma-glutamyl transpeptidase), SGPT (Serum glutamate pyruvate transaminase), TP (Total Protein), CHOL (Cholesterol) GLOB (Globulin) and TBILI (Total Bilirubin). The individual levels of these components and the interactions between them are the specific areas that a veterinarian will use to check against normal levels.
Elevated liver enzymes can be indicative of conditions or diseases that also occur in humans, or they may be distinctive to dogs only. High enzyme levels can also be caused by a number of other factors including trauma, artificial toxins, blood clots, low blood pressure, bile duct blockages, pancreatitis and many other conditions. Anesthetics and even some prescriptions can sometimes cause liver damage. Some normal fluctuations occur as well. SGPT for instance, can fluctuate to levels as high as two to three times normal levels due to the fact that this is an enzyme that is released in spurts when needed. Only a persistently high level of SGPT would be cause for alarm.
What heightened liver enzyme levels could mean for your dog
With all of the possible causes of high enzyme levels in mind, usually the most logical course of action is to retake the blood work in two to three weeks. The second blood test may show normal liver function, proving that the effect of the heightened liver enzymes were from a temporary source. However, a second confirmatory result may indicate that a follow-up battery of tests may be needed to determine the exact cause of the heightened liver enzymes. These causes can range from the serious, such as liver disease, to the benign, such as environmental toxins from pesticides and carpet cleaners that can be easily remedied.
As mentioned, certain drugs prescribed for your dog could also have an adverse effect on his or her liver. As one example, Dr. Bryce Fleming, D.V.M., of Saskatchewan’s Sherwood Animal Clinic, points to some drugs used in anti-convulsant treatments “Phenobarbital, primidone, phentoin. May cause liver disease in 6 to 15 % of all dogs on anti-convulsant therapy.” He goes one to say that “Inflammation seems related to dose.” This does not mean, of course, that the drugs should not be used, simply that their use requires monitoring for any dog needing them. If you have been using the same veterinarian for the entirety of your dog’s life, this will probably not be an issue, but it could be relevant if switching vets to one that is not familiar with your dog’s drug history.
If the cause is not immediately apparent from the chemical work or from a visual inspection, other tests may include urinalysis, x-rays or a liver biopsy. If a problem is found, the appropriate treatment is begun. Obviously, the first step would be to remove any toxic agents in the dogs environment (lawn chemicals, cleaning products). Keeping your dog well rested and in a controllable area will be part of the treatment, as well as carefully monitoring their diet. Any more serious medical problems would have to be dealt with on a case by case basis.
In summation, due to the number of functions of the canine liver, and its contact with such a large portion of the bloodstream, fluctuations in liver enzyme levels can occur. The causes can range considerably, and secondary testing should be applied to ensure proper diagnosis. Elevated liver enzyme in your dog can be worrisome, but is by no means a definite cause for alarm. Dr. Jon Geller, D.V.M. specifically says to be on the lookout for “vomiting, diarrhea, lethargy, fever, loss of appetite or other changes that went along with the abnormal results,” if those are present at the same time you are seeing high levels of liver enzymes on your dog’s charts, “there would be more urgency.”
Guest post by: Dr. Linda Kennedy MS SLP ND: Is an accomplished author and researcher. Although a lifetime Naturopath specializing in the treatment of people, she applies the same clinical principles to her pets and passion, the European Doberman. A breeder of quality verses quantity, her Doberman puppies are available only occasionally.