Cerebral injuries in neonatal encephalopathy treated with hypothermia: French LyTONEPAL cohort.

Background Hypothermia is widely used for infants with hypoxic-ischemic neonatal encephalopathy but its impact remains poorly described at a population level. We aimed to describe brain imaging in infants born at ≥36 weeks' gestation, with moderate/severe encephalopathy treated with hypothermia. Methods Descriptive analysis of brain MRI and discharge neurological examination for infants included in the French national multicentric prospective observational cohort LyTONEPAL. Results Among 575 eligible infants, 479 (83.3%) with MRI before 12 days of life were included. MRI was normal for 48.2% (95% CI 43.7-52.8). Among infants with brain injuries, 62.5% (95% CI 56.2-68.5) had damage to more than one structure, 19.8% (95% CI 15.0-25.3) showed a pattern-associating injuries of basal ganglia/thalami (BGT), white matter (WM) and cortex. Overall, 68.4% (95% CI 62.0-74.3) of infants with normal MRI survived with a normal neurological examination. The rate of death was 15.4% (95% CI 12.3-19.0), predominantly for infants with the combined BGT, cortex, and/or WM injuries. Conclusions Among infants with neonatal encephalopathy treated with hypothermia, two-thirds of those with normal MRI survived with a normal neurological examination at discharge. When present, brain injuries often involved more than one structure. Trial registration The trial was registered at ClinicalTrials.gov (NCT02676063). Impact In this multicentric cohort of infants with neonatal encephalopathy (LYTONEPAL) two-thirds survived with normal MRI and neurological examination at discharge. In total, 10% of newborns showed a pattern associating injuries of the basal ganglia-thalami, white matter, and cortex, which was correlated with a high risk of death at discharge. The evolution of MRI techniques and sequences in the era of hypothermia calls for a revisiting of imaging protocol in neonatal encephalopathy, especially for the timing. The neurological examination did not give evidence of brain injuries, thus questioning the reproducibility of the clinical exam or the neonatal brain functionality.