Bilateral third cranial nerve palsies in association with a ruptured anterior communicating artery aneurysm.

Third cranial nerve palsy occurring in a patient with an intracranial aneurysm is typically unilateral and associated with an internal carotid-posterior communicating or distal basilar artery aneurysm. In this report a patient with bilateral third cranial nerve palsies associated with rupture of an anterior communicating artery aneurysm is described. Raised intracranial pressure without brain herniation and compression of the third nerves within the perimesencephalic cisterns by focal subarachnoid clot are suggested as possible underlying mechanisms of the palsies, which showed complete recovery at 4 months after the hemorrhage and subsequent early aneurysm repair.