Utility of High-Dose Steroids in Treatment-Resistant Carotid-Cavernous Fistulas: A Case Report.

Introduction: Carotid-cavernous fistulas (CCFs) are rare arteriovenous communications between the carotid arterial system and the cavernous sinus that can result in vision-threatening and life-threatening complications. Severe cavernous sinus and orbital venous congestion is managed with prompt endovascular intervention to prevent irreversible cranial nerve and ocular pathology. While high-dose corticosteroids have been reported to improve clinical symptoms in a small number of cases of superior ophthalmic vein thrombosis (SOVT) secondary to CCF, their role in the management of severe orbital venous congestion without radiographically confirmed SOVT remains unclear. Case Presentation: We report the case of a 67-year-old female who developed a direct CCF following a high-speed motor vehicle collision. Two weeks after the event, she presented with progressive diplopia, right-sided ptosis, and headache. Diagnostic transradial cervical and cerebral angiography revealed a high-flow, direct internal right CCF with bilateral superior ophthalmic vein (SOV) and cavernous sinus opacification. Despite multiple transvenous coil embolizations and subsequent flow diverter stent placements, she continued to develop severe, progressive sequelae of orbital venous congestion without evidence of SOVT on imaging. Following initiation of high-dose oral corticosteroids 5 days prior to additional flow diverter stent placement, the patient experienced symptomatic improvement with subsequent recurrence found clinically following steroid taper and cessation. No changes were noted on her angiograms over this period, and her orbital congestion improved after restarting a high-dose corticosteroid pulse. A final curative trans-orbital direct SOV puncture for coiling was performed, resulting in complete symptom resolution. Conclusion: This case demonstrates that systemic corticosteroid therapy may be a valuable adjunctive treatment for CCF-associated, vision-threatening venous congestion refractory to standard endovascular intervention. Early recognition of progressive orbital venous congestion is critical to prevent permanent vision loss. A multimodal approach combining flow diversion, coil embolization, and corticosteroids may help achieve favorable outcomes in complex cases. This case adds to the limited literature supporting corticosteroid use in this challenging clinical scenario and highlights the importance of aggressive ophthalmologic monitoring following CCF diagnosis.