OBJECTIVE: The brain's inflammatory reaction to traumatic brain injury (TBI) generally peaks between 24 and 48 h after injury. This inflammatory cascade can be neuroprotective or may mediate secondary brain injury beyond the initial TBI. Therefore, circulating inflammatory markers may be useful for predicting outcomes in pediatric TBI. The goal of this study was to determine whether elevations in peripheral blood neutrophil-to-lymphocyte ratios (NLRs) are associated with adverse outcomes in pediatric TBI patients.
PATIENTS AND METHODS: 188 pediatric patients (0-18 years) presenting to our institution with TBI from 2007 to 2017 were retrospectively reviewed. Absolute neutrophil and lymphocyte counts from a complete blood count (CBC) were used to calculate NLRs on admission (<12 h) and approximately 24, 48, and 72 h after injury. Data points included Glasgow Coma Scale (GCS) on admission, presence of post-traumatic amnesia (PTA), loss of consciousness (LOC), and Glasgow Outcome Scale Extended Pediatric Version (GOS-E Peds) with a median outcome span of 86 days.
RESULTS: A one-way ANOVA demonstrated statistically significant differences in NLR at 24 h (p = 0.004) and 48 h (p=0.003) among patients stratified by GOS-E Peds. No significant differences in NLR were observed at any time point based on GCS or PTA. Patients who experienced LOC had a significantly higher NLR on admission (p=0.013) and at 24 h (p<0.001) than those who did not.
CONCLUSION: In this study, relatively higher NLRs at 24 and 48 h post-TBI were associated with worse outcomes in pediatric patients. This suggests that NLR may be a useful and cost-effective outcome predictor in pediatric TBI as well as a possible future target for therapeutic intervention, warranting larger prospective trials.