Traumatic carotid-cavernous sinus fistula accompanying abducens nerve (VI) palsy in blowout fractures: missed diagnosis of ‘white-eyed shunt’

We report the case of a 32-year-old woman with bilateral blowout fractures. She presented with diplopia showing impaired abduction of the left eye soon after trauma. No other orbito-ocular signs, such as exophthalmos, ptosis, or chemosis, were found. Orbital reconstruction was performed, but no improvement in her ophthalmoplegia was observed after surgery. A carotid angiography showed that she was suffering from a posteriorly draining carotid-cavernous sinus fistula with isolated abducens nerve palsy. Coil embolization was conducted under the consultation of a neurosurgeon, after which her ophthalmoplegia resolved fully. This is a rare case of posteriorly draining carotid-cavernous sinus fistula without classic orbito-ocular signs, the absence of which may cause diagnostic confusion.