Extreme neonatal jaundice

A raised serum bilirubin (hyperbilirubinemia) and consequent jaundice is a common feature during the neonatal period; more than half of all newborns develop mild jaundice – with serum bilirubin rarely exceeding 150 µmol/L – during the first week or two of life. This transitory phenomenon usually resolves spontaneously without any long-term health consequences. 

Some babies, however, develop more severe jaundice, and the neurotoxicity of bilirubin determines that the risk of permanent brain damage, caused by deposition of bilirubin in the brain (kernicterus) increases, as serum bilirubin rises above 350 µmol/L. Urgent treatment (phototherapy and/or exchange transfusion) to reduce serum bilirubin is required to avoid such damage. 

A recent Danish study, provoked by reports of a resurgence of kernicterus in recent years, sought to establish the incidence of extreme hyperbilirubinemia among term and near-term infants. During a two-year study period, 128,344 term or near-term babies were born in Denmark. 

Of these, 32 developed extreme hyperbilirubinemia, defined for the purposes of this study as a serum bilirubin which would trigger an exchange transfusion, according to agreed national guidelines. The actual peak serum bilirubin for these 32 babies ranged from 385 to 689 µmol/L (mean 492 µmol/L). 

The calculated incidence of extreme hyperbilirubinemia was 25 per 100,000 live births. The case histories of the 32 babies are reviewed in the paper. Twelve of the babies had clinical evidence of central-nervous-system involvement. Perhaps surprisingly, just over half of the babies (59 %) developed extreme hyperbilirubinemia whilst still in hospital. 

The authors make several recommendations aimed at reducing the incidence of this potentially devastating condition.