Hemiparesis without responsible hematomas in patients with subarachnoid hemorrhage undergoing early aneurysmal repair.

OBJECTIVE: The presence of hemiparesis on arrival in patients with subarachnoid hemorrhage (SAH) is presumed to affect their prognosis, and intracranial hematomas with a mass effect responsible for the hemiparesis are frequently observed in these patients. The purpose of this study was to clarify the characteristics and outcomes of patients who presented with hemiparesis on arrival and showed no responsible hematomas (hemiparesis w/o hematoma) having a mass effect on computed tomography.

METHODS: Consecutive SAH patients treated with surgery for ruptured cerebral aneurysms within 5 days of onset between 2003 and 2015 were retrospectively reviewed.

RESULTS: Hemiparesis w/o hematoma was present in 25 of 858 surgically treated patients (2.9%). Internal carotid artery (ICA) aneurysms were significantly more common in patients showing hemiparesis w/o hematoma than in the other patients (p<0.05). In 19 of 21 surviving patients (90.5%) with hemiparesis w/o hematoma on arrival, the hemiparesis improved at discharge. Favorable outcomes were achieved in 16 of 25 patients showing hemiparesis w/o hematoma (64%) and in 13 of 59 patients showing hemiparesis with hematomas (22.0%), and the difference was significant (p<0.05).

CONCLUSIONS: The hemiparesis could be expected to improve in SAH patients with hemiparesis w/o hematoma, and such patients appear to have a better prognosis than those having SAH with hemiparesis and responsible hematomas. A possible major mechanism of hemiparesis w/o hematoma based on the characteristics identified was a combination of transient ipsilateral hemispheric functional failure caused by the impact of aneurysmal rupture and transient ischemia of the perforators originating from the ICA.