Hemolysis

Hemolysis or haemolysis (hiːˈmɒlɪsɪs), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo or in vitro. One cause of hemolysis is the action of hemolysins, toxins that are produced by certain pathogenic bacteria or fungi. Another cause is intense physical exercise. Hemolysins damage the red blood cell's cytoplasmic membrane, causing lysis and eventually cell death. From hemo- + -lysis, from n αἷμα (haîma, "blood") + λύσις (lúsis, "loosening"). Hemolysis inside the body can be caused by a large number of medical conditions, including some parasites (e.g., Plasmodium), some autoimmune disorders (e.g., autoimmune haemolytic anaemia, drug-induced hemolytic anemia, atypical hemolytic uremic syndrome (aHUS)), some genetic disorders (e.g., Sickle-cell disease or G6PD deficiency), or blood with too low a solute concentration (hypotonic to cells). Hemolysis can lead to hemoglobinemia due to hemoglobin released into the blood plasma, which plays a significant role in the pathogenesis of sepsis and can lead to increased risk of infection due to its inhibitory effects on the innate immune system. Because the feeding process of the Plasmodium parasites damages red blood cells, malaria is sometimes called "parasitic hemolysis" in medical literature. See HELLP syndrome, Pre-eclampsia, and Eclampsia Hemolytic disease of the newborn Hemolytic disease of the newborn is an autoimmune disease resulting from the mother's antibodies crossing the placenta to the fetus. This most often occurs when the mother has previously been exposed to blood antigens present on the fetus but foreign to her, through either a blood transfusion or a previous pregnancy. Hemolytic anemia Because in vivo hemolysis destroys red blood cells, in uncontrolled, chronic or severe cases it can lead to hemolytic anemia. A hemolytic crisis, or hyperhemolytic crisis, is characterized by an accelerated rate of red blood cell destruction leading to anemia, jaundice, and reticulocytosis.