Bilateral carotid cavernous sinus fistula: a case report and review of the literature

Carotid cavernous fistula (CCF) is an abnormal vascular shunt from the carotid artery to the cavernous sinus. They are commonly classified based on hemodynamics, etiology or anatomically. Hemodynamic classification refers to whether the fistula is high or low flow. Etiology is commonly secondary to trauma or can occur spontaneously in the setting of aneurysm or medical conditions predisposing to arterial wall defects. Bilateral carotid cavernous fistulas are rare. We present a case of bilateral CCF secondary to trauma. Ophthalmology was urgently consulted to assess the patient in the intensive care unit (ICU) for red eye. The patient was found to have decreased vision, increased intraocular pressure, an afferent pupillary defect, proptosis, chemosis, and ophthalmoplegia. Subsequent neuro-imaging confirmed a bilateral CCF. The patient underwent two endovascular embolization procedures. Trauma is the most common cause of CCF and accounts for up to 75% of cases. Most common signs of CCF depend on whether it is high or low flow. High-flow CCF may present with chemosis, proptosis, cranial nerve palsy, increased intraocular pressure, diplopia, and decreased vision. Cerebral angiography is the gold standard diagnostic modality. First-line treatment consists of endovascular embolization with either a metallic coil, endovascular balloon or embolic agent. It is unclear in the literature if bilateral cases are more difficult to treat or have a different prognosis. Our patient required two endovascular procedures suggesting that endovascular intervention may have reduced efficacy in bilateral cases.