Acquired hemolytic anemia can be divided into immune and non-immune mediated forms of hemolytic anemia.
Immune mediated hemolytic anaemia (direct Coombs test is positive)
Autoimmune hemolytic anemiaWarm antibody autoimmune hemolytic anemiaIdiopathicSystemic lupus erythematosus (SLE)Evans' syndrome (antiplatelet antibodies and hemolytic antibodies)Cold antibody autoimmune hemolytic anemiaIdiopathic cold hemagglutinin syndromeInfectious mononucleosis and mycoplasma (atypical) pneumoniaParoxysmal cold hemoglobinuria (rare)Alloimmune hemolytic anemiaHemolytic disease of the newborn (HDN)Rh disease (Rh D)ABO hemolytic disease of the newbornAnti-Kell hemolytic disease of the newbornRhesus c hemolytic disease of the newbornRhesus E hemolytic disease of the newbornOther blood group incompatibility (RhC, Rhe, Kidd, Duffy, MN, P and others)Alloimmune hemolytic blood transfusion reactions (i.e., from a non-compatible blood type)Drug induced immune mediated hemolytic anemiaPenicillin (high dose)MethyldopaNon-immune mediated hemolytic anemia (direct Coombs test is negative)
Drugs (i.e., some drugs and other ingested substances lead to hemolysis by direct action on RBCs, e.g., ribavirin )Toxins (e.g., snake venom; plant poisons such as aesculin)TraumaMechanical (from heart valves, extensive vascular surgery, microvascular disease, repeated mechanical vascular trauma)Microangiopathic hemolytic anemia (a specific subtype with causes such as TTP, HUS, DIC and HELLP syndrome)Infections (Note: Direct Coombs test is sometimes positive in hemolytic anemia due to infection)MalariaBabesiosisSepticemiaMembrane disordersParoxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface proteins)Liver diseaseDrug induced hemolysis has large clinical relevance. It occurs when drugs actively provoke red blood cell destruction. It can be divided in the following manner:
Drug-induced autoimmune hemolytic anemiaDrug-induced nonautoimmune hemolytic anemiaA total of four mechanisms are usually described, but there is some evidence that these mechanisms may overlap.
