Immune mediated hemolytic anemia (IMHA), also known as auto-immune mediated hemolytic anemia (AIHA), is a disease in which the body's immune system, which is designed to attack and kill germs, attacks and kills the body's own red blood cells. The attack begins when antibodies, which are molecules made by the immune system to target germs, instead attach to and target the animal's own red blood cells for destruction. The red blood cells carry oxygen to the tissues, and the animal cannot survive without adequate oxygenation of the tissues.

The causes of IMHA remain largely unknown. While some cases of IMHA may be associated with a triggering event (cancer, infection, and perhaps even vaccinations), these events do not explain why the immune system misdirects its arsenal of weapons against the animal it is meant to protect.

IMHA occurs more often in dogs than in cats, in middle aged animals (3 to 8 years old), and in more females rather than males. While any breed can be affected, certain breeds develop IMHA more often than others do, such as the cocker spaniel, Springer spaniel, miniature poodle, Finnish spitz, Irish setter, Dachshund, bichon frise and Old English sheepdog.

For unknown reasons, there is an increased incidence of disease in the spring, with 40% of cases diagnosed in the months of May and June.

IMHA is a rapidly life-threatening disease. Even with appropriate treatment, this disease can be fatal.

What To Watch For

Pale gums

Yellow tinged gums or whites of the eyes

Dark or dark yellow urine

Tiring easily, weakness

Lethargy

Loss of appetite

Vomiting

Tachypnea (rapid breathing)