Hemolytic Anemia in Dogs
Dr. Leah Cohn
Hemolytic anemia is a disease process in which the red blood cells, the cells that carry oxygen and impart a red color to blood, are destroyed, resulting in a decreased number in the bloodstream. Red blood cells supply the body with oxygen, so when there are fewer of them, the animal lacks energy and tires quickly. Hemolytic anemia is often a rapidly life-threatening condition. Although there are a number of potential causes for hemolytic anemia, the most common is a disease known as immune mediated hemolytic anemia (IMHA). In this disease, the body's immune system, which is designed to kill germs, instead begins to kill the animal's own red blood cells.
Some types of germs and parasites infect the red blood cells directly. These infections can result in destruction of the red cells.
Certain toxins can also cause destruction of red cells. These include drugs like Tylenol, foods like onions, and metals like zinc, which is found in a surprising number of common items, including pennies.
Mechanical damage to the red blood cells can also result in their destruction. This can occur as a result of the cells being passed through twisted or damaged blood vessels.
There are hereditary diseases in which the red blood cells do not work normally, and these conditions may lead to premature destruction of the abnormal red blood cells.
What to Watch For
Weakness or tiring more easily than normal
Breathing more rapidly than normal
Very pale pink or white gums
A yellow tinge to the gums or the whites of the eyes
Your veterinarian will begin by asking detailed questions about what you have noticed that is out of the ordinary, and when these changes began. Also expect questions about your pet's diet, his elimination habits and the color of the stool and urine, any medications, including herbal supplements, your pet may be receiving, and when the most recent vaccinations were given.
Your veterinarian will complete a physical examination. This will include looking for evidence of bleeding, evaluating gum and eye color, listening to the heart and lungs, and palpating for swellings or organ enlargement.
A complete blood count (CBC) is essential in the evaluation of any animal with suspected anemia. This includes both a count of the various blood cell types, and an evaluation of the shape and size of the blood cells. It may also show parasites infecting the red cells.
A packed cell volume (PCV) or hematocrit is a simple measure of red blood cells.
A serum biochemical profile may be performed to evaluate organ function and the balance of salts in the body.
A urinalysis detects byproducts of red blood cell breakdown in the urine, as well as assessing kidney function.
A Coomb's test uses a small amount of the animal's blood to look for evidence that the immune system is causing the red cell destruction, or hemolysis.
Radiographs (X-rays) may be taken to look for evidence of metallic objects like pennies in the animal's stomach, or for evidence of enlarged or twisted organs.
Specific tests may be indicated to look for infections of the blood. These usually involve submitting a blood sample to a special laboratory.
Other tests may be indicated for an individual animal.
Blood transfusions may prove life saving. Either fresh blood or a concentrate of red blood cells may be administered through an intravenous catheter.
Artificial blood products may be used in place of real blood transfusions. These are not completely man-made, but are derived from components of cow blood.
Because immune system destruction of the blood is the most common cause of hemolytic anemia, animals will often be treated with corticosteroids to suppress the immune system.
Intravenous fluids may be indicated, whether or not the animal receives a blood transfusion.
Other treatments depend on the correct identification of the cause for hemolysis. For instance, if small, coin-shaped pieces of metal are revealed in the stomach on X-rays, they will need to be removed either with an endoscope, which is a fiberoptic tube passed through the mouth into the stomach, or via surgery.
If the gums are noted to be pale or white and the animal appears weak, seek emergency veterinary assistance. Minimize exercise and exertion while the pet is anemic. Administer prescribed medications exactly as directed, for the length of time specified.
Return your pet promptly for any recommended follow-up examinations and blood tests.