Spontaneous Resolution of a Bilateral Barrow Type D Indirect Carotid-Cavernous Fistula: A Rare Case Report and...

Background and Clinical Significance: Bilateral carotid-cavernous fistulas are rare clinical entities characterized by heterogeneous clinical presentations and variable outcomes. Case presentation: We report the case of a 69-year-old woman with a three-month history of progressive bilateral conjunctival hyperemia, proptosis, intermittent diplopia, and a left eye abduction deficit. Her systemic history included long-standing arterial hypertension and previous thyroidectomy with stable substitutive therapy. Comprehensive ophthalmologic, neurologic, and endocrine evaluations excluded more common causes of orbital congestion, including thyroid eye disease, orbital cellulitis, cavernous sinus thrombosis, and idiopathic orbital inflammation. The patient denied any history of recent trauma. Digital subtraction angiography (DSA) confirmed a bilateral, low-flow, indirect Barrow type D carotid-cavernous fistula (CCF) supplied by dural branches of both the internal and external carotid arteries, with marked reflux into dilated superior ophthalmic veins. DSA was essential, as prior CT and MRI studies did not identify any vascular abnormalities. The patient was scheduled for transvenous embolization; however, during the follow-up she noted gradual improvement in her condition. Repeat pre-procedural angiography performed approximately two months later demonstrated complete spontaneous closure of all shunts, accompanied by full clinical resolution. Conclusions: Owing to the exceptional rarity of bilateral indirect CCFs and the added occurrence of spontaneous closure, this case expands the limited existing literature and emphasizes the diagnostic challenges and the need for individualized treatment timing supported by multidisciplinary evaluation in low-flow dural carotid-cavernous fistulas.