Traumatic Brain Injury in the Immature Brain: Evolving Lesions, Divergent Mechanisms, and Therapeutic Horizons

Traumatic brain injury (TBI) is a major cause of disability and mortality among children and adolescents. A central concern in pediatric TBI is not only focal tissue cavitation but also progressive global and regional brain-volume loss, cortical thinning, white matter disruption, and the resulting impairment of neurodevelopmental function. In this review, “immature brain” is used as an umbrella term spanning neonatal, early postnatal or infant, juvenile or childhood, and adolescent stages; these stages are not treated as biologically equivalent. We analyze developmental vulnerability after TBI, compare focal lesion, tissue-loss, and brain-atrophy trajectories while distinguishing direct within-study age comparisons from cross-study interpretations, summarize experimental models with particular attention to focal and diffuse or white matter injury paradigms, and discuss MRI metrics, biomarkers, and candidate therapeutic strategies relevant to pediatric outcomes.