Background characteristics and neuropathology findings of medico-legal autopsy cases with and without β-amyloid precursor protein positive diffuse traumatic axonal injury.

The postmortem diagnosis of diffuse traumatic axonal injury (dTAI) relies on β-amyloid precursor protein (β-APP) immunohistochemistry. Most reports of factors associating with dTAI are decades old. We compared background characteristics and neuropathology findings of today's Finnish medico-legal autopsy cases with and without β-APP-positive dTAI (dTAI+ and dTAI-, respectively). The cases had suffered a head injury prior to death and underwent a full neuropathological examination including β-APP stain. Background and circumstantial data as well as neuropathology findings were collected from police documents, medical records, and autopsy and neuropathology reports. Prevalence ratios were calculated for each factor to facilitate comparisons between the dTAI+ and dTAI- groups. The dataset comprised 57 cases (66.7% males), with 17 classified as dTAI+ and 40 as dTAI-. Based on prevalence ratios, the factors that had at least two-fold prevalence among dTAI+ cases compared to dTAI- cases were: an unknown injury mechanism; concurrent epidural or subdural haemorrhage; and an accidental manner of death. In contrast, the factors that had at least two-fold prevalence among dTAI- cases compared to dTAI+ cases were: a short postinjury survival (<30 min); concurrent intracerebral/ventricular haemorrhage or contusion; vermal atrophy; and a natural or homicidal manner of death. This study revealed differences in circumstantial features and neuropathology findings between dTAI+ and dTAI- cases in today's medico-legal autopsy material. Data on typical case profiles may help estimate the prior probability of dTAI not only in medico-legal autopsies but also among living patients with head injuries.