What occurs when an infant becomes jaundiced?
The breakdown of a red blood cell (RBC) releases hemoglobin and produces bilirubin. The rate of bilirubin production in the newborn is two to three times that of an adult. There are several causes. • The fetus has more RBC’s per KG of body weight, due to the environment of reduced oxygen supply. At birth, respiration is established in an oxygen-rich environment and the surplus of RBC’s is no longer needed. They are then metabolized. • Neonatal RBC’s have an average life span of 70-90 days compared to that of an adult 120 days. • Heme, an essential molecule in oxygen-dependent metabolism and a potential source of bilirubin, is increased in the neonate. • Enterohepatic shunting is often increased in the neonate. The newborn gut lacks bacterial floras needed to convert bilirubin to a form that cannot be reabsorbed and thus excreted. The newborn bowel contains 10X the adult concentration of the intestinal enzyme beta-glucuronidase, which readily hydrolyzes conjugated back into the unconjug
