IMHA is a serious but treatable illness

Immune-Mediated Hemolytic Anemia (IMHA) is a type of anemia that occurs when the immune system becomes overstimulated and destroys red blood cells. Most dogs with IMHA survive with proper treatment, but this can be a life-threatening disease.

When a dog develops IMHA, the symptoms can include weakness, lethargy, exercise intolerance, and/or pale mucus membranes. The dog’s urine can turn to a dark orange or brown color. The gums, skin and sclera (the white part of the eye) may turn yellow. Some dogs have difficulty breathing, and some may develop a fever.

Many things can make a dog or cat more prone to developing the disease. The underlying cause could be an infection, cancer, recent medication or a recent vaccination. It is for those reasons that we generally recommend radiographs (X-rays) of the chest and an ultrasound of the abdomen to look for any underlying cause. Despite the search for an underlying problem, the cause of IMHA cannot be found in 60 percent to 80 percent of affected dogs.

To diagnose IMHA, other causes of anemia need to be ruled out, and a Coombs’ test and other blood tests will be sent to the lab.

Treatment involves a corticosteroid called prednisone, usually in combination with other drugs to suppress the immune system and stop it from attacking and destroying the red blood cells. Most patients need blood transfusions in early stages of the disease.

The medication doses are gradually decreased over time, usually during a three- to four-month period, and blood cell counts are monitored whenever there is a decrease in medication dose, to minimize the chances of a relapse. A small percentage of dogs can have a relapse, either during the reduction of drug doses or after the treatment. The best way to try to avoid recurrence is to have the red blood cell count monitored closely during therapy. We also recommend using caution with future vaccinations.

Dr. Kevin Mallery is a board-certified specialist in veterinary internal medicine. He is the hospital director at Veterinary Specialty Hospital North County in San Marcos (www.vshsd.com