Presentation and management of mesencephalic hematoma. Report of two cases.

Two patients presenting with a mesencephalic hematoma are reported. Clinical features, particularly paralysis of all vertical eye movements and a marked tendency to fall backwards when standing, allowed accurate localization of these lesions. In one case, the etiology was a proven arteriovenous malformation, and the other was suspected to be due to hypertensive arteriolar rupture. Deterioration resulted from further expansion of the mesencephalic mass in one patient. A subtemporal approach allowed excellent exposure of the midbrain for evacuation of the hematoma. The other patient developed hydrocephalus due to obstruction of the aqueduct and was treated successfully by placement of a ventriculoperitoneal shunt. Both patients survived, although one remains moderately disabled. The authors emphasize the importance of initial observation and supportive care in the stable patient with a mesencephalic hematoma. Surgery is indicated for those who show evidence of deterioration from rebleeding or hydrocephalus.