Abstract 162: Indirect Carotid Cavernous Fistula with Oculomotor Nerve Palsy Secondary to Trauma

Abstract

Introduction Intriguing and uncommon, we present a fascinating case of carotid‐cavernous fistula (CCF) following ocular trauma. Delving into medical nuances and outcomes, this reported case offers valuable insights for clinicians and researchers in the field of ophthalmology and interventional Neurology. Methods An elderly patient presented to the emergency department with diplopia and left eyelid ptosis two weeks after left ocular trauma. The patient had exotropia and hypotropia with restricted movement in all directions but mostly during adduction and infraduction which led to the diagnosis of oculomotor nerve palsy. Computer Tomography (CT) head was obtained which showed mild left proptosis with the prominence of the optic nerve sheath complex, CT angiography revealed asymmetric prominence of the left ophthalmic veins and enlarged left cavernous sinus with outward convex borders. CT face and mandible with IV contrast did not show any bony deformity. The patient underwent cerebral angiography that showed an indirect type 4 cavernous‐carotid fistula. Results A precise incidence of CCF fistula has not been reported so far in the literature but it is estimated to be present in 0.2 % of patients presenting with traumatic brain injury with an increased incidence of 4 % with basilar skull fractures. They can occur spontaneously or following closed skull injury, skull base fractures, or iatrogenically after craniotomies, endoscopic transsphenoidal or sinus surgery, and endovascular procedures. They can be classified based on angiographic arterial architecture (direct or indirect), hemodynamics (high flow or low flow), and etiology (spontaneous or traumatic). Type A are direct fistulas, whereas types B, C, and D are indirect fistulas. Direct CCFs often present with pulsatile exophthalmos, orbital bruit, chemosis, diplopia, ocular redness, orbital pain, swelling, swishing or buzzing sounds, headache, or vision loss. Indirect low‐flow CCFs may be asymptomatic and insidious in onset and mostly present with chemosis and conjunctival injection. Conclusion Indirect carotid‐cavernous fistula rarely occurs secondary to a head trauma without any bony deformity and it's even rare to have an oculomotor nerve palsy on presentation, it should be considered as an etiology when evaluating patients for ocular nerve palsies.