Hemolytic Anemia, Acquired

• • Fatigue, pallor, jaundice

  • Splenomegaly

  • Persistent anemia and reticulocytosis

Epidemiology

• • Autoimmune disorder that is either idiopathic (40-50%) or secondary to drug exposure, connective tissue diseases, or lymphoproliferative disorders

  • Classified according to the optimal temperature at which autoantibodies react with the red cell surface (warm or cold antibodies)

  • -Warm antibody: IgG autoantibodies directed against the Rh locus on the erythrocyte coat the cell and bind to IgG specific Fc receptors on macrophages in the spleen

    -Cold antibody: IgM autoantibodies are directed against the I red cell antigen; hemolysis occurs intravascularly and not within the spleen

  • Most common after age 50; occurs twice as often in women than in men

Symptoms and Signs

• • Fatigue

  • Mild jaundice

  • Fever

  • Splenomegaly

Laboratory Findings

• • Acute onset normocytic normochromic anemia

  • Reticulocytosis (> 10%)

  • Erythroid hyperplasia of the marrow

  • Elevation of serum indirect bilirubin

  • Serum haptoglobin is usually low or absent

  • Positive direct Coombs test

• • Rarely, a sudden, severe onset hemolytic anemia produces hemoglobinuria, renal tubular necrosis, and a 40-50% death rate

  • May be associated with systemic lupus erythematosus and chronic lymphocytic leukemia

  • Drugs commonly implicated include methyldopa, penicillin, quinidine

Rule Out

• • Other causes of hemolytic anemia

  • -Hereditary hemolytic anemias

    -Thrombotic thrombocytopenic purpura

    -Disseminated intravascular coagulation

    -Infection

• • CBC count

  • Serum bilirubin

  • Reticulocyte count

  • Peripheral blood smear

  • Serum haptoglobin

  • Bone marrow biopsy

  • Coombs test

When to Admit

• • Severe anemia

When to Refer

• • All cases should be managed in conjunction with a hematologist

• • Drug-induced hemolytic anemia: Terminate exposure to the agent.

Surgery

• • Splenectomy is indicated for patients with warm-antibody hemolysis meeting the following criteria:

Indications

• • Failure to respond to 4-6 weeks of high-dose corticosteroid therapy

  • Relapse when corticosteroids are withdrawn

  • Contraindications to corticosteroid therapy

  • Chronic high-dose corticosteroid therapy

Contraindications

• • Cold-antibody hemolytic anemia

Medications

• • Corticosteroids

  • IV immune globulin

Treatment Monitoring

• • CBC count

Complications

• • Pigment gallstones

Prognosis

• • 75% remission rate with medical treatment; 25% are permanent

  • Relapses may occur after splenectomy

References