Middle cerebral artery thrombosis following blunt head trauma

Stroke caused by occlusion of an intracranial artery following blunt head trauma is a rare event. Traumatic dissections of the middle cerebral artery have been reported while thrombosis is very rare. We describe a case of fatal thrombosis of the left middle cerebral artery that occurred in the time interval between 2 and 6 hours after an apparently minor head trauma in a motor vehicle accident. The 25-year-old woman was in normal health on admission to the hospital. Two hours later the patient manifested nystagmus and vomiting. Six hours later she was aphasic with right hemiparesis. Twenty-four hours later the patient was comatose. A third CT scan performed at that time showed a wide infarct of the left cerebral hemisphere and a hyperdense left middle cerebral artery. The patient died 5 days after the collision. The autopsy confirmed the presence of the cerebral infarct and revealed thrombosis of the left middle cerebral artery. Microscopically, the transverse rupture of the intima and of the elastic lamina along the whole circumference of the vessel was found at the beginning of the thrombosed tract. We conclude that the blunt head trauma caused a partial rupture of the wall of the left middle cerebral artery with consequent thrombosis of the vessel and cerebral infarct. Based on the anatomy of the middle cerebral artery and on the review of the morphological literature we propose that the 2 types of lesion, the dissection and the thrombosis, that may follow closed head trauma, might depend on a common denominator that is the primitive rupture of the intima and elastic lamina.