Abstract
A rare case of cerebral infarction due to traumatic occlusion of the right common carotid artery is reported with reference to its pathogenetic mechanisms associated with dog bite injury.
A 59-year-old man developed disturbance of consciousness, left hemiparesis and dysarthria immediately after he was bitten by a dog on the right side of his neck. On admission he was stuporous and there were several dog bite wounds in paralell with the right sternocleidomastoid muscle. He exhibited a conjugate ocular deviation to the right side, a right Homer's syndrome, severe dysarthria, right hemiparesis including his face, and a left hemisensory deficit. He also showed anosognosia of the left hemiparesis and unilateral spatial agnosia of the left. Upon admission, the cranial CT which demonstrated an extensive low density area in the territory of the right middle cerebral artery and a localized low density area in the right thalamic region. Digital subtraction angiography revealed a complete occlusion of the right common carotid artery at its origin. The cervical CT showed a lack of contrast in the right common carotid artery. Since the cerebral infarction had already occurred, surgical treatment was not carried out for this traumatic arterial lesion. The patient had been treated with hypertonic solution and anti-platelet aggregation agent. The followup angiography performed on 12th day of admission failed to show recanalization of the occluded right common carotid artery.
This occlusive lesion of the right common carotid artery was considered to be directly associated with the dog bite injury. The usual time lapse between the trauma to the carotid artery and onset of neurological symptoms is reportedly about 8-10 hours. This interval is believed to correspond to the time necessary for the evolution of the thrombus and subsequent occlusion of the lumen of the vessel. Our patient was different from those with thrombotic occlusion due to the traumatic intimal laceration in having developed neurological symptoms immediately after the trauma. Two other possible pathogenetic mechanisms were considered for the traumatic occlusion of the right common carotid artery in this case. One is a traumatic dissection of the intima that occluded the true lumen of the artery. Another possibility is a hemorrhage in the media or subintimal planes.
