Unilateral sixth nerve palsy due to spontaneous subarachnoid hemorrhage

Background: Unilateral abducens nerve palsy (ANP) caused by ruptured anterior communicating artery (ACoA) aneurysm have been rarely reported. Most of the ANP reports due to spontaneous subarachnoid hemorrhage (SAH) are bilateral paralysis. Facilitate cerebrospinal (CSF) circulation through microsurgery could help to solve this neurological deficit after SAH. Usually the nerve that is committed by direct compression is the oculomotor, for example by a posterior communicating segment of internal carotid artery aneurysm. However, abducens palsy generally is not caused by direct compression.

Objective: This study aims to describe a rare case of unilateral abducens nerve palsy after SAH and a literature review considering cranial nerve alterations after SAH.

Methods: After authorization through a consent form, it is reported a case of patient with ruptured aneurysm and abducens palsy. Details considering neurological exam and neuroimaging are described. Also a literature review was performed.

Results/case report: A patient was admitted on emergency department with sudden onset of headache, vomiting and left unilateral sixth nerve palsy. Computed tomography angiography revealed cisternal SAH and a 4 mm saccular aneurysm on anterior communicating artery. The patient underwent surgical aneurysm clipping with concomitant lamina terminalis and Lilliequist’s membrane fenestration. Few days after the procedure she evolved with complete ANP regression and received discharge without neurological deficits.

Conclusions: Microsurgical lamina terminalis and Lilliequist’s membrane fenestration performed concomitant to the surgery for aneurysm clipping may be a factor, which contributes to more rapid clinical improvement in patients who develop ANP after SAH.