Definition of Idiopathic autoimmune hemolytic anemia:

Idiopathic autoimmune hemolytic anemia is a drop in the number of red blood cells due to increased destruction by the body's defense (immune) system.

Causes, incidence, and risk factors:

Idiopathic autoimmune hemolytic anemia is an acquired disease that occurs when antibodies form against a person's own red blood cells. In the idiopathic form of this disease, the cause is unknown.

Idiopathic autoimmune hemolytic anemia accounts for one-half of all immune hemolytic anemias.

There are other types of immune hemolytic anemias in which the cause may result from an underlying disease or medication. The disease may start quickly and be very serious.

Risk factors are not known.

Symptoms:

• Dark urine
• Fatigue
• Pale color (pallor)
• Rapid heartbeat
• Shortness of breath
• Yellow skin color (jaundice)

Signs and tests:

An examination may reveal an enlarged spleen.

Tests include:

• Direct Coombs' test
• Hemoglobin in the urine
• Indirect Coombs' test
• Red blood cell count and serum hemoglobin
• Reticulocyte count
• Serum bilirubin levels
• Serum haptoglobin

Treatment:

The first therapy tried is usually a steroid medication, such as prednisone. If steroid medications do not improve the condition, removal of the spleen (splenectomy) may be considered.

Therapy to suppress the immune system is usually given if the person does not respond to steroids and splenectomy. Medications such as azathioprine (Imuran), cyclophosphamide (Cytoxan), and rituximab (Rituxan) have been used.

Blood transfusions are given with caution, because of the potential that blood may not be compatible and may cause further hemolysis.

Expectations (prognosis):

Adults may have long-term disease that keeps returning. In children the anemia is usually short-lived.

Complications:

• Infection (as a complication of treatment)
• Severe anemia

Calling your health care provider:

Call your health care provider if you notice symptoms of anemia.

Prevention:

There is no known prevention for idiopathic autoimmune hemolytic anemia, because the cause is unknown.