Objective: We sought to clarify the features of kernicterus in preterm infants.
Methods: The subjects of this study were 8 preterm infants with athetoid cerebral palsy whose gestational ages were < or =34 weeks. We retrospectively investigated clinical, laboratory, MRI, and brainstem auditory evoked potential (BAEP) findings.
Results: Gestational age was < or =26 weeks in 6 of the 8 infants, and birth weight was <1000 g in 5 infants. Serious postnatal complications with systemic deterioration were observed in 3 infants. Total bilirubin levels were measured frequently in the majority of infants; peak values of >15 mg/dL were observed in 3 infants. No infant showed neurologic symptoms characteristic of classical acute bilirubin encephalopathy during the neonatal period. Dystonic posture and abnormal muscle tone were first recognized within 6 months' corrected age in all patients. During infancy, MRI was performed in 7 infants. Abnormal high-intensity areas were observed in the bilateral globi pallidi in all 7 infants. However, MRI during the neonatal period or after 1 year's corrected age showed no abnormal findings. BAEP measurements were abnormal in 7 of the 8 infants.
Conclusions: Preterm infants with athetotic cerebral palsy showed rather homogeneous features, similar to term infants with kernicterus, with marked hyperbilirubinemia. This combination of clinical, laboratory, neuroimaging, and neurophysiological data will contribute to the increased recognition of preterm infants with kernicterus.