An acquired form of hemolytic anemia caused by interaction of certain drugs with the immune system, resulting in antibody production against the red blood cells and premature red blood cell destruction.

Alternative Names

Immune hemolytic anemia secondary to drugs; Anemia - immune hemolytic - secondary to drugs

Causes, incidence, and risk factors

Drug-induced immune hemolytic anemia occurs when certain drugs interact with the red blood cell membrane, causing the cell to become antigenic (the body identifies the cell as tissue not belonging to the body). Antibodies form against the red blood cells. The antibodies combine with the affected red blood cells and result in their premature destruction. The incidence is rare in children. Drugs that can cause secondary immune hemolytic anemia are penicillins, cephalosporins, levodopa, methyldopa, mefenamic acid, quinidine, salicylic acid, sulfonamides, Thiazide diuretics, antazoline, chlorpromazine, isoniazid, streptomycin, and Motrin. Drug-induced hemolytic anemia is most often associated with G6PD deficiency .

Signs and tests

A

physical examination may show an enlarged spleen .

A

direct Coombs' test is positive.

An

indirect Coombs' test is positive if the offending drug is added to the test.

Indirect bilirubin

levels are elevated.

Serum haptoglobin

may be low.

Hemoglobin

may be present in the urine.

Hemosiderin may be present in the urine.

Urine and fecal urobilinogen are increased.

An absolute

reticulocyte count is elevated.

A

CBC shows red blood cell count and hemoglobin are low.

Treatment

Discontinuation of the suspected causative drug may alleviate or control the symptoms. Treatment with prednisone is the first additional therapy that may be tried. Blood transfusions with carefully typed packed red blood cells may be advised for severe symptoms.

Expectations (prognosis)

The outcome is expected to be good. The process subsides when the offending agent is eliminated from the body.

Complications

Death caused by severe

anemia rarely occurs.

Transfusion can cause a

transfusion reaction .

Calling your health care provider

You should see your health care provider any time that dark urine and jaundice occur, particularly if other symptoms also develop after taking a medication.

Prevention

If the disorder occurs, the individual should avoid the offending drug and its analogues (similar medications) in the future.