Cavernous Sinus Syndrome in a Traumatic Dissecting Aneurysm of the Internal Carotid Artery

We report a rare case of a missed intracavernous internal carotid artery dissecting aneurysm occurring as a complication of the base of skull fracture with severe brain injury causing acute cavernous sinus syndrome with permanent vision loss. A 31-year-old Myanmar lady had an alleged motor vehicle accident and suffered severe traumatic brain injury with multiple intracranial bleeds, multiple facial bone and base of skull fractures, and limb fractures. At one week post-trauma, she had severe right eye proptosis with vision loss, ophthalmoplegia, chemosis, and high intraocular pressure. She was suspected clinically to have a traumatic cavernous carotid fistula and a lateral canthotomy and cantholysis was performed. The patient was scheduled for an embolization of the fistula but during cerebral digital subtraction angiography, a dissecting aneurysm instead was noted at the right internal carotid artery at the cavernous segment. A cerebral computed tomography angiography and venography showed right cavernous sinus and right superior ophthalmic vein thrombosis. The patient was started on antiplatelet agents and underwent successful stenting-assisted coiling of the aneurysm, and her right eye proptosis gradually resolved. While awaiting definitive treatment of the aneurysm, the patient had severe exposure keratopathy and despite intensive hydration and antimicrobial treatment, it later developed into a fungal corneal ulcer. A temporary tarsorrhaphy was done and the ulcer gradually healed into a significant corneal scar and the final visual acuity of her right eye was no light perception. The underlying cause of cavernous sinus syndrome is diverse and unique. A thorough assessment and appropriate neuroimaging should be performed to arrive at the proper diagnosis in a timely manner. This is in order to prevent delays in the definitive treatment and irreversible ocular morbidity.