Fatal Traumatic Brain Injury With Traumatic Axonal Injury, From a Nonpenetrating Sponge Round: A Forensic Case Report

Although morbidity and fatalities related to nonpenetrating kinetic impact projectiles (KIPs), including rubber bullets and sponge rounds, have been reported, fatal traumatic brain injury resulting from these projectiles remains uncommon. A 38-year-old incarcerated male sustained a nonpenetrating sponge round impact to the frontotemporal region of the head during an altercation. The impact resulted in severe traumatic brain injury with traumatic axonal injury, ultimately resulting in death. Autopsy findings included subdural and subarachnoid hemorrhage, coup and contrecoup cortical contusions, and cerebral edema. Midline brainstem (Duret) hemorrhages were identified, consistent with increased intracranial pressure and axial displacement. Histologic examination demonstrated both traumatic and ischemic axonal injury. No skull fractures were identified. This case documents fatal neurotrauma resulting from a nonpenetrating kinetic impact projectile and emphasizes the role of neuropathological examination in determining injury severity. Given the increasing use of KIPs in correctional and crowd-control settings, this report adds a documented example of fatal traumatic brain injury with traumatic axonal injury following nonpenetrating projectile impact. Recognition of the potential for severe head injury from nonpenetrating projectiles has implications for forensic investigation and the evaluation of kinetic impact munition use.