Anemia, Hemolytic

Key Features

• Generally classified according to whether the defect is intrinsic or extrinsic to the red blood cell (RBC)

• Intrinsic defects have been described in all components of the red blood cell, including the membrane, enzyme systems, and hemoglobin; most of these disorders are hereditary

• External factors are immune and microangiopathic hemolytic anemias and infections of red blood cells

Clinical Findings

• Symptoms of anemia

• Jaundice, pigment gallstones, cholecystitis in chronic cases

• Palpable spleen

Diagnosis

• Serum haptoglobin may be low but is neither specific nor sensitive

• Reticulocytosis present unless second disorder (infection, folate deficiency) superimposed on hemolysis

• Transient hemoglobinemia occurs with intravascular hemolysis

• Hemoglobinuria occurs when capacity for reabsorption of hemoglobin by renal tubular cells exceeded

• Positive urine hemosiderin test indicates prior intravascular hemolysis

• Hemoglobinemia and methemalbuminemia occur with severe intravascular hemolysis

• Indirect bilirubin elevated, total bilirubin elevated to ≤ 4 mg/dL; higher bilirubin elevations may indicate hepatic dysfunction

• Serum lactate dehydrogenase is elevated in microangiopathic hemolysis; may be elevated in other hemolytic anemias

Treatment

• See Treatment of specific anemias

• Folic acid, 1 mg orally once daily

• Transfusions possible