Carotid cavernous fistula: A rare but treatable cause of ophthalmoplegia - A case report

Carotid cavernous fistulas (CCFs) are a rare but debilitating entity that may present with orbital or cerebral venous hypertension. CCFs may pose diagnostic and management pitfalls for clinicians as they can initially be misdiagnosed as primary orbital pathology or nonarteriovenous shunting-related cavernous sinus pathology. Furthermore, the resolution of pulsatile tinnitus could be an ominous sign in patients with untreated dural arteriovenous fistula. We describe a case of a 56-year-old male who presented with progressive right eye proptosis, congestion, decreased visual acuity, limited duction, exophthalmos, and pulsatile tinnitus. The patient had poor response to antibiotics and steroids. Magnetic resonance imaging brain showed significant inflammation involving the right orbit and atypical enhancement of the basal frontal lobe adjacent to the orbit. Cerebral angiography revealed an indirect right CCF and right sigmoid sinus thrombosis with stenosis of the right internal jugular vein. No clear predisposing factor was identified. Given the rapidly progressive nature of the condition, the patient successfully underwent endovascular treatment with transvenous approach to preserve flow in the internal carotid artery while ensuring occlusion of the fistula. A triad of proptosis, eye congestion, and signs of turbulent flow such as tinnitus or orbital bruit should raise suspicion for CCF. An interesting feature in this patient is that CCF may have occurred secondary to sigmoid sinus thrombosis with accompanying small cortical vein drainage. Our case highlights the importance of early recognition and timely intervention to ensure the resolution of orbital hypertension-related symptoms in rare cases of CCFs.