Natural Wellness Newsletter

Welcome to our first online issue of the Natural Wellness Newsletter.

Our online newsletter will cover our feature article that appears in our quarterly printed version. If you wish to receive a copy, please contact us and we will be happy to send it to you.

What is AIHA???

Auto Immune Hemolytic Anemia (AIHA) is a disease where the body attacks its own red blood cells (RBC) and destroys them. A pet suffering with AIHA will have a lower-than-normal number of red blood cells within the blood. This is termed anemia. The normal range for the packed cell volume (PCV) or hematocrit is 37-55% (the ratio of the volume of packed red cells to the whole blood).

AIHA is classified as a primary immune disease. No underlying cause of the immune destruction can be found after an exhaustive clinical and laboratory evaluation. A secondary disease is called immune-mediated hemolytic anemia (IMHA). IMHA refers to all anemias that occur when the immune system inadvertently destroys its own blood cells secondary to an immune attack directed against an underlying condition such as cancer, endocarditis, heartworm or by unidentifiable causes as in AIHA.

The number of AIHA cases increases yearly and it is often misdiagnosed. Knowing what to look for can clearly be to your advantage.

 What are the symptoms of AIHA???

When a large percentage of red blood cells (RBC) are affected, and they are removed faster then they can be replaced, the animal shows external signs of the disease.

The clinical signs of AIHA are usually gradual and progressive, but occasionally an apparently healthy pet suddenly collapses in an acute hemolytic crisis. The signs are usually related to lack of oxygen supply. The hemoglobin in RBC is the primary carrier of oxygen in the blood. Signs include weakness, lethargy, anorexia, and an increase in the heart rate and respiration. Heart murmurs, pale mucous membranes (gums, eyelids, etc.), and discoloration in the urine and/or stool may also be present. More severe cases also have a fever and icterus (jaundice), which is a yellow discoloration of the gums, eyes, and skin. This is due to a buildup of bilirubin, one of the breakdown products of hemoglobin.

The diagnosis of AIHA/IMHA is usually made on these clinical signs as well as a complete blood count (CBC). The CBC usually shows a regenerative anemia with spherocytes. Spherocytes are a special type of red blood cell that develops in IMHA. The blood samples may auto-agglutinate (clump). A Coombs test may be done to support the diagnosis.

Why My Pet???

Unfortunately no one knows why an individual pet develops AIHA/IMHA. Certain breeds such as cocker spaniels and poodles are at a higher risk than other breeds. Middle-aged female dogs are also at a higher risk. However immune-mediated hemolytic anemia may occur in any breed at anytime.

Typically, the veterinary medical field has not discovered why an individual dog gets AIHA/IMHA. However, evidence suggests that recent vaccinations (DHLPP) may be associated with a higher incidence of IMHA and so has the administration of certain medications like sulfa-trimethoprim antibiotics. Dogs with serious infections or cancers in their body may also develop IMHA. The thought for the underlying cause is that something (i.e., vaccine, cancer cells) triggers the immune system to react and to create antibodies.

Accidentally the antibodies also destroy the red blood cells and sometimes also the platelets (idiopathic thrombocytopenic purpura); and therefore, the first sign of illness may be the anemia.

Is There A Cure??? 

AIHA is better thought of as a disease that is controlled rather than cured. Medications are used to decrease the hyperactivity of the immune system and suppress the abnormal immune response directed against RBC.

Treatments may need to be given indefinitely, or at least for several months. Most dogs are on medications for at least 4-6 months, some much longer. Dogs that have had AIHA once are more likely to get it again, particularly if they are weaned off medicines very rapidly (less than 2 months).

Summary 

AIHA/IMHA is a life threatening immune disease that can cause damage to vital organs through the lack of oxygen supply associated with the resultant anemia. Owners of pets with AIHA/IMHA face a guarded to poor prognosis for the pet at the time of diagnosis. If an underlying disease such as cancer is discovered the prognosis becomes complicated by the limitations associated with the underlying cause as well.

Additionally, the destruction of RBC can result in development of blood clotting disorders and a systemic inflammation syndrome that looks like a severe infection clinically the after effects of these can also cause organ damage to kidneys, lungs and other organs resulting in death or prolonged hospitalization.

For more information about AIHA, please contact us.

© Natural Wellness For Pets 2003