Slowly Recovering Isolated Bilateral Abducens Nerve Palsy after Embolization of Ruptured Anterior Communicating Artery Aneurysm

Bilateral abducens nerve palsy related to ruptured aneurysm of the anterior communicating artery (ACoA) has only been reported in four patients. Three cases were treated by surgical clipping. No report has described the clinical course of the isolated bilateral abducens nerve palsy following ruptured ACoA aneurysm obliterated with coil. A 32-year-old man was transferred to our institution after three days of diplopia, dizziness and headache after the onset of a 5-minute generalized tonic-clonic seizure. Computed tomographic angiography revealed an aneurysm of the ACoA. Magnetic resonance imaging showed focal intraventricular hemorrhage without brain stem abnormalities including infarction or space-occupying lesion. Endovascular coil embolization was conducted to obliterate an aneurysmal sac followed by lumbar cerebrospinal fluid (CSF) drainage. Bilateral paresis of abducens nerve completely recovered 9 weeks after ictus. In conclusion, isolated bilateral abducens nerve palsy associated with ruptured ACoA aneurysm may be resolved successfully by coil embolization and lumbar CSF drainage without directly relieving cerebrospinal fluid pressure by opening Lillequist's membrane and prepontine cistern.