抄録
This is a case report of traumatic brain stem contusion. The pathogenesis was considered to be due to direct injury by tentorial margin. A 20-year-old male was involved in an automobile accident and was transferred in an unconscious state. The Glasgow Coma Scale score on admission was 8. Computed tomography (CT) scan showed a linear high-dense lesion at the left dorso-lateral midbrain without other significant intracranial lesions. He was treated conservatively. He regained consciousness several hours later, but drowsiness persisted for 3 weeks. He initially presented the left one-and-half syndrome and the right hemiparesis, which improved after a month. Follow-up CT scans showed a contusional lesion at the level of the ponto-mesencephalic junction which resolved in 3 weeks. The neurological deficits 6 months after the accident were right hemihypesthesia, left cerebellar sign, and right trochlear nerve palsy. He could not return to his previous occupation due to the persisting ataxia.
The mechanism of this injury was supposed to be due to a direct injury by the tentorium cerebelli for the following reasons. The location of injury coincides with the level of the tentorium cerebelli. The injury started at the brain stem surface. The tentorial margin was closely located, to the brain stem in this case. Similar CT findings were reported in shear injuries, in which the prognosis was graver and follow-up CT scans showed diffuse brain atrophy. Therefore, the importance of differentiating between two mechanisms at the acute stage is emphasized.
