Immune Mediated Hemolytic Anemia (IMHA) is the latest “unknown” disease to get our attention here at the Knoxville Dog Health Examiner. Surprisingly common, IMHA has been described in a host of dog breeds of all ages and genders, as well as in both cats and humans. It appears most frequently in young to middle-aged dogs.
Often idiopathic in nature, it may arise with little warning. Owners report dogs deteriorating rapidly within a period of a few days, and clinical signs include lethargy, loss of appetite, vomiting, jaundice, anemia (often indicated by pale gums), sudden loss – or “blowing” – of coat and changes in urine color. In the case of our 10 year-old hound mix Snoopy, all the above symptoms except vomiting and jaundice were present within a 48 hour period of onset.
The most important thing to do if you think your dog may have IMHA is to take him or her to your vet immediately. There is a small window of opportunity for diagnostics and outpatient care if the disease is caught early, but most cases are more advanced and require hospitalization by the time they are diagnosed. Delaying diagnostics and treatment can be deadly.
In simple terms, IMHA rarely has a known cause, and it stimulates the body’s immune system (white blood cells) to search out and destroy its red blood cells. Comprehensive blood work usually indicates the potential presence of the disease by revealing extreme anemia. A Coombs test may confirm the diagnosis, but often treatment must proceed before confirmation. The combination of a transfusion to temporarily replenish the red cells and heavy doses of a steroid such as prednisone to suppress the body’s immune response will show whether or not the dog then has the ability to regenerate new red cells. If regeneration occurs (by measuring stable or increasing hemaotcrit levels in blood chemistry), the diagnosis is very likely IMHA. If, on the other hand, hematocrit levels continue to drop, other potential underlying causes such as leukemia and lymphoma need to be investigated. For a more through scientific explanation, please click here.
If caught extremely early, steroid intervention alone may arrest the progression of the disease; in most cases, however, aggressive care – including one or more blood transfusions – is required. Despite our veterinarian’s experience with the disease and subsequent early and accurate diagnosis, our dog Snoopy required two transfusions within five days of his initial trip to the clinic. He then spent a few more days in critical care before coming home. He was one of the lucky ones, as mortality rates for this condition can be quite high.
Once home, the real work begins, as IMHA has a very slow path to recovery. One study indicates that while 85% of dogs that live 60 days beyond the initial diagnosis ultimately survive to live a normal life span, complete remission is not guaranteed. Usually, the patient will require decreasing doses of steroids over time as the body adjusts to both the disease and the treatment. While that occurs, anything the could overstimulate immune function is to be avoided. This includes exercise and unsupervised play, so management of care becomes a real challenge. Fortunately, even highly energetic dogs are less likely to protest due to the lingering fatigue caused by the disease.
If all goes well, several months to a year or more down the road, equilibrium or remission is achieved and normal life can resume. Although IMHA presents an arduous path for both owner and dog, it’s not impassible and survival is both possible and likely if diagnosis and treatment are timely and aggressive.
If you enjoyed reading this article, please click the ‘subscribe’ button at the bottom of the page to be notified every time a new Knoxville Dog Health article is published.