1. In a prospective cohort study, several mild cases of neonatal encephalopathy (NE) not eligible for therapeutic hypothermia had significant acute brain injury on magnetic resonance imaging (MRI).
2. Of patients with acute injury who did not receive therapeutic hypothermia, only 2/5 had abnormal amplitude integrated electroencephalography (aEEG) recordings, suggesting aEEG and clinical examination alone may be insufficient to identify NE.
Evidence Rating Level: 2 (Good)
Study Rundown: Neonatal Encephalopathy (NE) is defined by abnormal neurological function in the first few days of life due to brain injury. It most commonly results from birth asphyxia and cerebral hypoxia. Although therapeutic hypothermia has been shown to be neuroprotective in severe cases of NE, mild NE has often been excluded from most studies and practice guidelines. This study aims to address this treatment practice by evaluating MRI outcomes for patients who were evaluated for NE but did not meet criteria for therapeutic hypothermia treatment (mild NE). Of the 39 infants included in the study with mild NE, 5 (12.8%) infants demonstrated brain injury on MRI imaging, with only 2/5 infants displaying abnormal EEG recordings. This study is limited by the small sample size, low occurrence rate (5 cases), and lack of long-term neurological follow-up leading to unknown clinical significance of injury. Future studies are required to determine if neuroimaging should be utilized for early identification of brain injury and NE that may be missed with aEEG and clinical examination methods alone. Overall, this small study suggests that current therapeutic hypothermia protocols may be missing a significant number of infants with mild NE that would potentially benefit from treatment. MRI may be useful in identifying this subset of infants.
Click here to read the article in the Journal of Pediatrics
Relevant Reading: Therapeutic hypothermia initiated within 6 hours of birth is associated with reduced brain injury on MR biomarkers in mild hypoxic-ischaemic encephalopathy: a non-randomised cohort study
In Depth [Prospective Cohort]: This prospective observational study enrolled infants >34 weeks gestational age at one tertiary level NICU between April 2019 and August 2021. Of 172 eligible infants, 39 were included in the analysis. Of the 39 infants enrolled, 28 (72%) were monitored with aEEG >1 hour. Therapeutic hypothermia was used based on clinical examination and grading of NE severity using the Neonatal Encephalopathy Score (NES), which categorizes infants into mild, moderate, and severe NE. NES scores between 1 and 12 are consistent with mild NE. MRI imaging was performed at 2 days of age. In total, there were 12 infants (31%) with abnormal MRI findings, which included acute injury, chronic injury, extra-axial findings, and incidental findings. Of the 5 infants with acute injury, the MRI imaging was associated parenchymal signal abnormality and diffusion restriction suggestive of NE. Two of the cases of acute injury had significant white matter injury in the occipito-parietal regions. None of the 5 reported cases had deep nuclear grey matter involvement.
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