Cytotoxic edema is associated with injury severity but not abusive mechanism in young children with traumatic brain injury

Background: Cytotoxic Edema (CE) is a form of brain parenchymal injury hypothesized to be associated with abusive mechanism and poor outcome for young children with traumatic brain injury. CE is reliably identified by magnetic resonance imaging but not by computed tomography. Objective: We sought to test the association of CE with injury severity, mechanism (abusive or non-abusive) and functional outcome in a large cohort of young children who all had magnetic resonance imaging. Participants and setting: Retrospective cohort study of children <6 years old admitted for traumatic brain injury between January 2011 – June 2020 and who had MR. Methods: Two pediatric neuroradiologists determined CE presence; mechanism of injury was determined by reviewing child protection team notes. Injury severity was measured using the injury severity score (ISS); functional outcome at hospital discharge and 6–12 months later was measured using the functional status score (FSS). Results: We identified 431 eligible children with traumatic brain injury. CE was associated with injury severity (Median [IQR] ISS for those with CE was 18 [17–26] vs. 17 [11–18] for those with no CE) and functional status at discharge (Median [IQR] FSS 9 [7–11] vs 6 [6–8] without CE) and 6–12 months from injury (Median [IQR] FSS 8 [6–10] vs 6 [6–8] without CE). CE was not associated with injury mechanism (OR 0.78; 95%CI 0.52–1.17). Conclusion: While CE was associated with injury severity and outcome, it was not associated with injury mechanism. Prior associations may reflect increased injury severity for abused children.