The Functional Basis of Physiologic Jaundice of the Newborn

Abstract

Jaundice in the newborn infant is a clinical sign which may lead both the clinician and investigator into vast areas of physiology and disease. Included within these areas of concern may be such widely disparate problems as infantile Gaucher’s Disease, ABO hemolytic disease, neonatal hepatitis, prematurity, biliary atresia and kernicterus (1). The list is legion, but what these situations have in common is the retention of bile pigment in the tissues of the body and in the circulating plasma. In the neonate, as in the older child and adult, hyperbilirubinemia may be classified into those disorders in which conjugated bilirubin (direct-reacting) accumulates (i.e. neonatal hepatitis, biliary atresia and certain metabolic disorders) and those in which unconjugated bilirubin (indirect-reacting) accumulates. Physiologic hyperbilirubinemia of the newborn is of the unconjugated type.