Immune Mediated Anemia

Overview

This disease occurs when the patient’s body begins to destroy it’s own red blood cells. Depending on the cause, the clinical signs can develop rapidly or over a longer period of time. It occurs in both dogs and cats.

Causes

The body will detect either an antibody or antigen on the surface of the red blood cell and will consider the cell "foreign". Infectious agents such as Ehrlichia, feline leukemia, Mycoplasma (Haemobartonella), and Leptospira can all deposit foreign material on the cells. Certain medications such as cephalosporins and methimazole can also cause the body to destroy it’s own cells. Sometimes a reason or cause can not be determined and the patient is diagnosed with idiopathic autoimmune hemolytic anemia.

Symptoms

These pets generally have sudden signs that include collapse, weakness, pale mucous membranes, vomiting, increased respiration and increased heart rate. Sometimes the only signs seen are blood in the urine or stool, anorexia, and exercise intolerance.

If an underlying cause can be identified (Ehrlichia, medication reaction) then it will need to be addressed appropriately. Some patients with severe anemia will need to be hospitalized for blood transfusions and prevention of DIC, a potentially fatal cascade of events that can occur in immune-mediated anemia. All patients will need to be on prednisone to shut off the body’s destruction of the red blood cells. If prednisone is not effective, azathioprine is added to the therapy.This disease is frustrating due to the complications that can occur such as DIC, pulmonary thromboembolism, and arrhythmias. Patients that completely recover tend to relapse in the future. Many patients need to be on high doses of steroids long-term or for life and have to adjust to the side effects seen with the medication.