Delayed Deterioration in Isolated Traumatic Subarachnoid Hemorrhage

Isolated traumatic subarachnoid hemorrhage (SAH) in association with mild traumatic brain injury is considered to be a less severe finding that is not likely to require surgical intervention. No previous reports have described cases warranting craniotomy for isolated traumatic SAH by itself.

We report 2 cases of minor head trauma with isolated traumatic SAH that showed delayed clinical deterioration requiring immediate surgical intervention. Initial computed tomography showed isolated traumatic SAH in the basal cistern and Sylvian fissure in both cases. Angiography showed no aneurysmal source. Within 24 hours of each accident, both disturbance of consciousness and hemiparesis deteriorated. Follow-up computed tomography showed formation of intracerebral hematoma adjacent to the Sylvian fissure. Intraoperative findings showed abruption injury of a perforating branch arising from the middle cerebral artery (MCA) as the cause of bleeding. Impact at the time of injury could have caused traction on the MCA in the Sylvian fissure, resulting in abruption of the perforator.

Isolated traumatic SAH seen in the basal cistern and Sylvian fissure carries a risk of late deterioration. A possible cause of hematoma expansion is abruption of a perforating branch arising from the MCA at the time of head injury. When hematoma expansion is identified, surgical evacuation of the hematoma is indicated. Surgical evacuation should be safely performed with the knowledge of the point of bleeding in such patients.