Background characteristics and neuropathological findings of medico-legal autopsy cases with chronic alcohol use and acute head injury.

Chronic alcohol use is often associated with traumatic brain injury (TBI). This study aimed to compare background characteristics, injury circumstances, primary head injuries, and secondary brain injuries among TBI cases with and without a documented history of chronic alcohol use. The sample comprised neuropathologically examined medico-legal autopsy cases with acute head injuries from Helsinki, Finland, over the years 2016-2022. Data on chronic excessive alcohol use were collected from medical records and police files; other background and circumstantial data were collected from medical records, police files, and cause-of-death investigation documents; and data on primary head injuries and secondary brain injuries were collected from autopsy and neuropathology reports. The dataset comprised 47 cases, of whom 19 had a history of chronic alcohol use (40.4%). Assault was the most common circumstance of injury among chronic alcohol users (47.4%) while falls prevailed among control cases (32.1%); unknown circumstances were common among both groups. There were no statistically significant differences in the prevalence of primary head injuries or postinjury survival between the groups. As for secondary brain injuries, hypoxic-ischaemic neuronal injury was significantly more common among chronic alcohol users in the frontal cortex (84.2% vs. 28.6%), parietal cortex (84.2% vs. 32.1%), hippocampus (63.2% vs. 25.0%), and lenticular nucleus (73.7% vs. 21.4%). Our findings suggest that chronic alcohol users may not necessarily have more diverse or complex primary injuries, but they may have more extensive secondary injuries. Further research should aim to explore the potential aetiology of hypoxic-ischaemic neuronal injury among chronic alcohol users.