hematology and oncology
Overview of Hemolytic Anemia
Etiology of Hemolytic Anemia
Hemolysis can be classified according to whether the hemolysis is Extrinsic: From a source outside the red cell; disorders extrinsic to the RBC are usually acquired. Intrinsic: Due to an defect within the red cell; intrinsic RBC abnormalities (see table Hemolytic Anemias ) are usually inherited. Causes of disorders extrinsic to the RBC include Drugs (eg,quinine,quinidine, penicillins,methyldopa,ticlopidine,clopidogrel) Immunologic abnormalities (eg, Autoimmune Hemolytic Anemia , Infections Mechanical injury ( Microangiopathic Hemolytic Anemia , eg, prosthetic heart valve) Reticuloendothelial hyperactivity ( Hypersplenism ) Toxins (eg, lead,copper) Infectious organisms may cause hemolytic anemia through the following mechanisms: Direct action of toxins (eg,Clostridium perfringens, alpha- or beta-hemolytic streptococci, meningococci) Invasion and destruction of the RBC by the organism (eg,Plasmodiumspecies,Bartonellaspecies,Babesiaspecies) Antibody production (eg, Epstein-Barr virus, mycoplasma). Defects intrinsic to the RBC that can cause hemolysis involve abnormalities of the following: RBC membrane Cell metabolism Hemoglobin structure Abnormalities include hereditary cell membrane disorders (eg, Hereditary Spherocytosis and Hereditary Elliptocytosis ), acquired cell membrane disorders (eg, 