Isolated contralateral abducens palsy in direct carotid-cavernous fistula

Post-traumatic direct carotid-cavernous fistulas may develop in patients with a closed head injury. The classical presentation is the Dandy's triad-chemosis, pulsatile proptosis and orbital bruit. Associated findings may include orbital pain, dilated episcleral corkscrew vessels, vision deficit and cranial nerve palsies. Cranial nerves-oculomotor (III), trochlear (IV), ophthalmic (V1), and maxillary (V2) divisions of trigeminal and the abducens (VI) lie in close association of the cavernous sinus. Abducens nerve (VI) lies close to the intracavernous internal carotid artery, within the substance of the sinus and is hence easily susceptible to vascular insult. The two sinuses connect across the midline and communicate freely with each other. Back pressure changes can present with the same sided or bilateral cranial nerve palsies. We report a rare association of a long-standing left-sided carotid-cavernous fistula with right eye abduction deficit and contralateral abducens palsy.