Haemolysis is the lysis or the breaking open of red blood cell (erythrocyte) causing the release of hemoglobin into the surrounding fluid. It has several causes, such as the exposure of erythrocytes to toxins and poisons, bacterial haemolysins, immune reactions like specific complement-fixing antibodies, hypotonicity, alteration of temperature, treatments such as hemodialysis, etc. Anaemia resulting from haemolysis either due to an intrinsic defect in the red blood cell (hereditary spherocytosis or ellipsocytosis, enzyme defects, haemoglobinopathy) or an extrinsic damaging agent is referred to as haemolytic anaemia, e.g. autoantibody (autoimmune haemolytic anaemia), iso antibody, parasitic invasion of the cells (malaria), bacterial or chemical haemolysins, mechanical damage to erythrocytes.
Haemolytic anaemia is a form of anaemia caused by haemolysis. The haemolysis may be intravascular, i.e. the haemolysis in the blood vessels, or extravascular, i.e. elsewhere in the body. Haemolytic anaemia may also be either hereditary or acquired. Haemolytic anaemia that is hereditary may be due to defects in erythrocyte production, in hemoglobin production, or in erythrocyte metabolism.
Acquired haemolytic anemia, in turn, may be due to immune related causes (such as in cold agglutinin disease and autoimmune haemolytic anaemia). It may also be caused by lead poisoning such as in non-immune haemolytic anemia.
- Hemolytic anemia