By Dr. Becker
Today we’re going to discuss autoimmune hemolytic anemia or AIHA. The condition is also called immune mediated hemolytic anemia (IMHA).
AIHA is a potentially life-threatening disease in which an animal’s immune system destroys its own red blood cells. Antibodies produced by the immune system to fight pathogens instead target the body’s red blood cells and destroy them. Red blood cells are necessary to carry oxygen to the tissues of the body, and animals cannot survive without adequate oxygenation of all of the body’s tissues.
Triggers for Autoimmune Hemolytic Anemia
Autoimmune hemolytic anemia can be either a primary or secondary disease. If it’s a primary disease, there is no underlying cause that can be identified. Primary AIHA is rare in cats.
In secondary AIHA, the immune system produces red blood cell antibodies in response to an underlying condition such as cancer, chronic inflammatory disease, a drug reaction, or exposure to an infectious agent. Newborns can acquire this disease from their mother’s first milk, which is colostrum, although this is pretty rare.
The surface of the red blood cells becomes altered by an underlying disease process or a toxin. These alterations catch the attention of the immune system, which sees them as foreign invaders or pathogens. The immune system targets the altered red blood cells and destroys them through a process known as hemolysis, either within the red blood cell vessels or as they circulate through the spleen or liver.
Some of the known underlying triggers for secondary autoimmune hemolytic anemia are infectious agents like leptospirosis, babesia, ehrlichia, and the feline leukemia virus. Also heartworm disease, IBD, certain drugs like the sulfa drugs, heparin, and quinidine, hypersensitivity reactions (for example, to bee stings), and vaccines can all over-stimulate the immune system and cause AIHA.
Link Between Vaccines and Autoimmune Hemolytic Anemia
According to the traditional veterinary community no “statistically significant association” has been proven between vaccines and AIHA, and they are only willing to consider a link if the onset of the disease occurs within four weeks of a vaccination.
Now, those of us in the holistic veterinary community absolutely believe there is a direct and prevalent link between vaccines and autoimmune hemolytic anemia.
As a holistic vet working in a large traditional vaccine clinic early in my career, I saw a lot of cases of AIHA – one or two a month. However, for the last 11 years since I’ve been in private practice, I’ve not seen a single case in my own patients. I believe this is because in my own practice, we titer rather than automatically give traditional adjuvanted vaccines.
The cases of AIHA I see now are referred from traditional vet practices that are probably continuing to over-vaccinate.
Which Pets Are More Likely to Get AIHA?
Autoimmune hemolytic anemia is a life-threatening condition. It is much more common in dogs than cats. When it does occur in cats, it usually happens when they’re young, and the Somali breed is predisposed to the disease.
AIHA can occur in dogs of all breeds, both sexes, and at any age. But studies suggest it is more prevalent in middle-aged spayed female dogs. There may be a risk of acquiring the disease more commonly in May and June. Holistic veterinarians correlate this to early spring vaccines rather than simply the season of the year. But certainly, traditional veterinarians would argue the opposite.
Breeds predisposed to autoimmune hemolytic anemia include the cocker spaniel, miniature poodle, Irish setter, and the Old English sheepdog.
The symptoms of autoimmune hemolytic anemia are similar to those seen in other types of anemia and can include:
|Loss of appetite
|Lack of energy, tendency to tire easily
||Yellow tinge to the gums and whites of the eyes
|Excessive thirst or urination
||Bloody or dark, tarry stool
Jaundice, which is a yellowing of the gums and eye tissue, occurs when the liver can’t efficiently process bilirubin. Bilirubin is the yellow byproduct of the breakdown of red blood cells.
A healthy liver can process the byproducts of red blood cells as they reach the end of their normal lifespan. But in an animal with autoimmune hemolytic anemia, the liver can’t keep up with the amount of bilirubin produced by the immune system’s destruction of the red blood cells. This is why pets with autoimmune hemolytic anemia have a yellow discoloration of the mucus membranes, which is especially noticeable in the gums and eyes. You can also sometimes see it on the inside of the earflaps in both dogs and cats.
Other symptoms vets look for are an enlarged liver, enlarged spleen, enlarged lymph nodes, and potentially an intermittent heart murmur.
A diagnosis of autoimmune hemolytic anemia can’t be made until other causes of anemia have been ruled out. Unfortunately, this means a number of diagnostic tests will be necessary for a definitive diagnosis. Your vet will take a complete history and perform a medical examination.
Diagnostic tests will include a complete blood count, a serum biochemical profile, and a urinalysis. A packed cell volume or PCV is a simple and fast test to determine the red blood cell quantity. Testing for reticulocyte count will show if there are enough new red blood cells being produced, and a saline agglutination test may show whether the red blood cells are clumping normally.
Other tests may include looking for infectious diseases and parasites, a Coombs test to check for an immune system reaction in the bloodstream, and a flow cytometry test. X-rays and ultrasounds are sometimes ordered to rule out evidence of cancer or metastatic disease (cancer that has spread).
If your cat is suspected of having anemia, a test for feline leukemia and FIV may be needed to check for an underlying cause.
Conventional treatment for AIHA is usually aggressive. The goal is to stop the destruction of red blood cells, so they can regain their ability to efficiently move oxygen to all the body’s tissues.
If there is any known underlying condition contributing to the destruction of red blood cells, this must be addressed. And the animal’s health must be supported until their red blood cell supply is back to normal.
If the disease is life threatening at the time of diagnosis, the pet may need blood transfusions immediately. This can be risky because while the immune system is still attacking red blood cells, an increase in the number of them through transfusion can trigger an even more aggressive immune system response.
Sometimes a blood substitute called Oxyglobin is used. This is a substance that has the ability to carry oxygen to all of the body’s tissues and potentially avoid the risk associated with transfusion of real blood to your dog or cat.
Drug therapy is also typically introduced in the form of a corticosteroid like prednisone to intentionally suppress the immune system, so it will slow down or stop attacking the red blood cells. These drugs are usually given in very high doses, and if the animal’s response isn’t sufficient, even stronger immuno-suppressants are administered, including chemotherapeutic agents.
Needless to say, all these drugs have pretty significant side effects, and some of them are quite serious.
Some minor success has been seen with the use of intravenous immunoglobulins, which come from human blood. In rare instances, usually only in specialty veterinary hospitals, a process called plasmapharesis, which removes the antibodies from the blood, is also used. Sometimes a splenectomy is performed.
Supportive Care for AIHA Patients
Supportive care for autoimmune hemolytic anemia is really critical, and can include recurrent transfusions, nursing support, hospitalization, medications and IV fluids to keep the animal as hydrated and healthy as possible.
Holistic veterinarians offer adjunctive therapies while the initial crisis is being treated.
The Chinese herb Yunnan paiyao has been proved to effectively reduce bleeding anywhere in the body. Homeopathic phosphorous can also be very beneficial in this condition, as can the traditional Chinese medicinal formula Qing Ying Tang.
Many animals with autoimmune hemolytic anemia unfortunately require long-term or even intermittent lifetime therapy, because relapses are really common.
It’s critical, in my opinion, that these animals’ immune systems never be unnecessarily stimulated again by any type of vaccine.