Infantile acute subdural hematoma.

A retrospective analysis of the infantile acute subdural hematoma was made with special reference to its pathogenesis. In 11 of 15 cases, the hematomas were bilateral or a contralateral subdural fluid collection was present. In 7 of 11 patients who underwent operation the collection was bloody fluid and/or clotted blood. In 3 patients, a subdural membrane, as seen in adult chronic subdural hematoma, was found. In only 1 patient with unilateral hematoma was clotted blood present without subdural membrane. The thickest collection of clotted blood was in the parasagittal region. It is postulated that in most cases hemorrhage occurs after minor head injury, from the bridging veins near the superior sagittal sinus, into a pre-existing subdural fluid collection such as chronic subdural hematoma or subdural effusion with cranio-cerebral disproportion, and that infants without intracranial disproportion are unlikely to have acute subdural hematoma caused by minor head injury.