Abstract
Objective: Characteristics of abducens nerve palsy caused by subarachnoid hemorrhage (SAH) originating from ruptured vertebral artery (VA) dissecting aneurysm were investigated.
Methods: Twenty-six patients with SAH from ruptured VA dissecting aneurysm were treated in our hospital during the last 10 years. Seven patients developed abducens nerve palsy, 3 men and 4 women aged 43–75 years (mean 57 years). Their clinical courses were reviewed retrospectively.
Results: On admission, two of the 7 patients were Hunt and Kosnik grade II and the others were grade V. Abducens nerve palsy was bilateral in 3 cases, unilateral in 3, and on unknown side in 1. All ruptured aneurysms were accompanied by ipsilateral palsy. Computed tomography demonstrated diffuse SAH (especially a thick clot in the prepontine cistern) in 6 of the 7 patients and acute hydrocephalus in 2 patients. Abducens nerve palsy had completely disappeared in 5 patients and was incompletely resolved in 2.
Conclusions: Abducens nerve palsy caused by SAH originating from ruptured VA dissecting aneurysm was found in 7 of our 26 patients (26.9%). Abducens nerve palsy occurred on the side ipsilateral to the ruptured aneurysm, associated with a thick clot in the prepontine cistern. Of 7 patients, five were completely recovered and the others (2) were improved. Therefore, mechanical injuries caused by direct compression by the clot or bloody jet flow from the rupture could be responsible for such abducens nerve palsy. However, false localizing sign due to acute hydrocephalus could not be ruled out.
