Chapter 18 - Hemolytic Disease of the Newborn

Abstract

This chapter discusses the pathogenesis, clinical features, and laboratory diagnosis of the different entities causing hemolytic disease of the newborn (HDN) and the therapeutic interventions. HDN is characterized by decreased life span of red blood cells (RBCs) due to accelerated destruction. Apart from anemia, which may be severe and life-threatening in many of the conditions associated with HDN, the immaturity of the neonatal liver in handling the bilirubin load from breakdown of RBCs, and the unique susceptibility of the neonatal brain to toxic effects of unconjugated bilirubin make hemolytic disease a therapeutic emergency in newborn infants. Alloimmune HDN is due to the action of transplacentally transmitted maternal IgG antibodies on paternally inherited antigens present on fetal red cells, but absent on the maternal red cells. Intrauterine fetal transfusions and exchange transfusions are used in case of severe HDN. Intensive phototherapy is also found to effectively reduce bilirubin levels and decrease the need for exchange transfusions for hyperbilirubinemia in ABO and Rh HDN. Recombinant human erythropoietin is shown to decrease the need for postnatal transfusions in infants with late hyporegenerative anemia of Rh hemolytic disease, the hyporegenerative anemia noted in neonates with Kell HDN, and even in infants with anemia due to hereditary spherocytosis. Transfusion of blood compatible with not only the D-antigen but also Kell and other Rh antigens is advocated for premenopausal women to prevent alloimmunization.