Unexpected Orbital Worsening after Traumatic Carotid-cavernous Fistula Endovascular Closure: A Diagnostic and Treatment Challenge

Abstract Carotid–cavernous fistulas (CCFs) are the rare vascular lesions characterized by abnormal shunting between the carotid artery and cavernous sinus. Endovascular embolization remains the treatment of choice; however, paradoxical worsening of orbital symptoms may occur despite angiographic cure. We report the case of a 40-year-old woman presenting with left eye proptosis, chemosis, orbital bruit, and visual impairment. Digital subtraction angiography revealed a direct (Type A) CCF, which was successfully treated with transarterial coil embolization. Unexpectedly, the patient developed worsening orbital signs on the postoperative day 3. Repeat angiography confirmed complete occlusion without recanalization or superior ophthalmic vein thrombosis. The symptoms resolved completely with conservative corticosteroid therapy. This case highlights that inflammatory responses or venous stasis may mimic persistent CCF and be misinterpreted as treatment failure. Recognizing these mechanisms is critical to avoid unnecessary re-intervention.