Carotid Cavernous Fistula: A Case Report of a Rare Diagnosis and Presentation.

Periorbital swelling can differ from simple allergic conjunctivitis, orbital cellulitis, and cavernous sinus thrombosis, as well as rapidly expanding retrobulbar hemorrhage. An uncommon cause is the carotid-cavernous fistula (CCF), an abnormal arteriovenous connection between the carotid artery and the cavernous sinus. CCFs can cause periorbital swelling, diplopia, cranial nerve palsies, and ultimately vision loss secondary to retinal detachment, vitreous detachment, or intracranial hemorrhage. CCFs are strongly associated with previous head trauma, especially basilar skull fractures, and with connective tissue disorders. However, according to the patient, she had no history of connective tissue disorder or previous trauma. She presented to the clinic with right periorbital swelling, chemosis, and mild, painful extraocular movements of two months' duration and was referred to the emergency department for imaging. CT angiography (CTA) showed a right high-flow CCF. The patient was admitted for cerebral angiography and embolization. The procedure was successful, and her symptoms resolved completely.