Hyperbilirubinemia in preterm infants in Japan: New treatment criteria

In 1992, Kobe University proposed treatment criteria for hyperbilirubinemia in newborns using total serum bilirubin and serum unbound bilirubin reference values. In the last decade, chronic bilirubin encephalopathy has been found to develop in preterm infants in Japan because it can now be clinically diagnosed based on an abnormal signal of the globus pallidus on T2-weighted magnetic resonance imaging and abnormal auditory brainstem response with or without apparent hearing loss, along with physical findings of kinetic disorders with athetosis. We therefore revised the Kobe University treatment criteria for preterm hyperbilirubinemic infants in 2017. The three revised points are as follows: (i) newborns are classified under gestational age at birth or corrected gestational age, not birthweight; (ii) three treatment options were created: standard phototherapy, intensive phototherapy, and albumin therapy and/or exchange blood transfusion; and (iii) initiation of standard phototherapy, intensive phototherapy, and albumin therapy and/or exchange blood transfusion is decided based on the total serum bilirubin and serum unbound bilirubin reference values for gestational weeks at birth at <7days of age, and on the reference values for corrected gestational age at 7days of age. Studies are needed to establish whether chronic bilirubin encephalopathy can be prevented using the 2017 revised Kobe University treatment criteria for preterm infants in Japan.