Immune-Mediated Hemolytic Anemia
Immune-mediated hemolytic anemia (IMHA) is a leading cause of anemia in dogs. Red blood cells normally responsible for carrying oxygen throughout the body are destroyed by the body’s own immune defenses. This destruction of red blood cells is triggered when the immune system creates antibodies against components on the surface of the red blood cells. The reason for the immune reaction to the red blood cells is unknown, but may be associated with the administration of certain medications.
Breeds of dogs most likely to be affected include poodles, Old English Sheepdogs, Irish Setters and Cocker Spaniels, although any dog may develop the disease. The disease usually affects dogs between the ages of two and eight years old, but is more common in female dogs.
The most common symptoms of IMHA include an increased sensitivity to cold (leading dogs to warm locations), decreased appetite, weakness, depression, vomiting, diarrhea and pale or yellow colored gums and eyes. The yellow discoloration, or jaundice, is a result of the breakdown of red blood cells. Another sign of red blood cell break down is hemoglobinuria, or the production of a dark orange or brown colored urine.
A diagnosis of IMHA is especially likely in female dogs with signs of a hemolytic anemia. The veterinarian can also find laboratory signs, which suggest hemolytic anemia by submitting a blood sample. A Coomb’s test can determine whether the immune system of the pet is involved.
Immune-mediated hemolytic anemia is treated with a combination of glucocorticoids, such as dexamethasone and prednisone. These medications decrease the immune response, preventing the destruction of red blood cells. Other medications are also used to treat the disease, including cimetidine and danazol. Your veterinarian will choose the combination that is most appropriate for your pet.