Hemolytic anemia – a form of anemia – (synonyms: Anemia, hemolytic; Hemolytic anemia; Hemolytic icterus; ICD-10-GM D55-D59: Hemolytic anemias) refers to all forms of anemia characterized by increased breakdown or decay (hemolysis) of erythrocytes (red blood cells) that cannot be compensated for by increased production in the red bone marrow. The normal life span of erythrocytes is approximately 120 days, while the erythrocyte survival time in hemolytic anemia is less than 100 days.
The hemolytic anemias belong to the hyperregenerative anemias, i.e., they are characterized by compensatory increased erythropoiesis (formation of mature erythrocytes from hematopoietic stem cells of the hematopoietic bone marrow) with peripheral reticulocytosis (increased occurrence of immature erythrocyte precursors (reticulocytes) in the blood).
Also typical of hemolytic anemia is a normal mean hemoglobin content per erythrocyte (MCH) and normal mean single erythrocyte volume (MCV). This is referred to as normochromasia and classifies the anemia as a normocytic normochromic anemia.
Hemolytic anemia can be divided into two major groups, which in turn are divided into many subgroups:
- Corpuscular hemolytic anemias.
- Enzymopathy (genetic enzyme defects), e.g.
- Membrane defects, e.g. spherocytosis (spherocytic anemia; most common hemolytic anemia in Northern Europe).
- Hemoglobinopathies (disorders of hemoglobin synthesis), e.g., thalassemia, sickle cell anemia (see below of the disease of the same name).
- Extracorpuscular hemolytic anemias.
- Alloantibodies – blood group antibodies as in transfusion incidents; rhesus incompatibility.
- Autoimmune hemolytic antibodies:
- Anemia caused by the appearance of antibodies against the body’s own red cells, as in heat or cold antibodies-AIHA (autoimmune hemolytic anemia); isoantibodies (e.g., Morbus haemolyticus neonatorum).
- By infectious diseases such as malaria
- Microangiopathic disorders as in hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP; Moschkowitz syndrome, Moschcowitz syndrome).
- Metabolic disorders as in Zieve syndrome (characterized by a triad of: Hyperlipoproteinemia (also hyperlipidemia; lipid metabolism disorder), hemolytic anemia and alcohol toxic liver damage with icterus/ jaundice).
- Drug-induced immune hemolysis
- Chemical damage as in intoxications (poisonings) with snake venoms.
- Mechanical damage such as caused by artificial heart valves
- Thermal damage such as caused by burns
Course and prognosis: depends on the underlying disease. In severe anemia, blood transfusion may be required.