Hippocampal pathology in fatal non-missile human head injury.

The hippocampus has been known to be involved in fatal non-missile human head injury, although detailed histopathology of this lesion has yet to be described. This report documents the frequency and distribution of hippocampal damage in a consecutive series of 112 fatal human non-missile head injuries. Damage to the hippocampus was noted in 94 cases (84%). Lesions always involved the CA1 subfield and were bilateral in 70 cases. Other subfields of the hippocampus were involved less frequently. Lesions were focal in the majority of cases (58%). Pathological evidence of high intracranial pressure was present in 86% of the cases. Hypoxic brain damage in other regions of the brain was present in 74% of cases. Thus, the hippocampus is frequently damaged in fatal non-missile human head injury. The pattern of this damage is similar to that observed in experimental head injury. Hypoxia and high intracranial pressure are likely to contribute to the occurrence of human traumatic hippocampal damage but other mechanisms, such as excitotoxicity, are likely to be operative.