Immune-mediated hemolytic anemia (IMHA) is a potentially deadly condition in dogs. You may also see it as autoimmune hemolytic anemia (AIHA) or autoimmune anemia. Regardless of what you call it, in this disease involves the destruction of red blood cells by your dog’s own immune system gone rogue.
Your dog’s red blood cells are responsible for transporting nutrients and oxygen to cells throughout the body, as well as picking up carbon dioxide, waste products including dead or damaged cells, and toxins. Your dog needs adequate red blood cells to live.
Normally, your dog’s body has a nice balance between new red blood cells being manufactured in the spleen and bone marrow and worn out or damaged cells being removed by the spleen. When the immune system destroys red blood cells faster than they are produced, your dog will become anemic.
What Causes IMHA in Dogs?
Unfortunately, the most common causes idiopathic, which means that the reason for the disease is never determined. American Cocker Spaniels have the highest risk of all breeds, which suggests a genetic predisposition.
Potential secondary causes abound, with tick-borne diseases at the head the list, followed by drug and vaccine reactions. Other potential causes include bee stings, snake bites, viruses, bacteria, and even cancer.
Signs of IMHA in Dogs
Any of the signs listed below justify a trip to the veterinary clinic. While IMHA can be treated, it has a high mortality rate. The sooner the treatment starts, the better the chance for a successful outcome.
Clinical signs you may notice include:
- Weakness
- Lethargy
- Pale gums
- Jaundice (ears, gums, groin)
- Small pinprick hemorrhages in the groin (called petechia)
- Nose bleeds
- Rapid breathing
- Racing heartbeat
Treatment for IMHA in Dogs
Some quick bloodwork will be done to verify that the problem is IMHA, and then treatment will start. At a minimum, most dogs will require intravenous (IV) fluids and some corticosteroids, and/or immunomodulating drugs. That generally means prednisone and a medication like cyclosporine. Expect your dog to spend some days in the hospital. Blood transfusions are frequently required, often more than one. In severe cases, stem cell therapy has been tried.
If an underlying cause is identified, treatment is aimed at clearing that up as well as treating the immediate symptoms. Sadly, even with rapid treatment, up to 50% to 70% of dogs will die. For those dogs who get released from the hospital, there is a relapse rate of about 15%. Most dogs will remain on at least some medications for life. Frequent rechecks are important to try and catch any relapse early on.
Can You Prevent IMHA in Dogs?
There is no real way to prevent IMHA other than regular preventive care, avoiding parasites like ticks, trying to avoid bees and snakes, and doing regular physical examinations to catch any cancers as soon as possible.
Know your dog’s family health history. For example, if littermates have had drug reactions, avoid those medications for your dog. Astute observation by you for any symptoms and responding right away increases your dog’s odds for a positive outcome.
