Carotid-Cavernous Fistula: A Rare but Treatable Cause of Rapidly Progressive Vision Loss.

An 89-year-old woman with hypertension, hyperlipidemia, stroke, deep venous thrombosis, and atrial fibrillation presented with 4 days of right eye (OD) redness and swelling and intermittent diplopia. An ophthalmologic evaluation revealed visual acuity 20/50 OD. There was limited abduction OD, right upper and lower lid erythema and edema, and conjunctival injection. Funduscopic examination was unremarkable. Erythrocyte sedimentation rate and C-reactive protein were normal. Follow-up ophthalmologic examination 2 weeks later showed visual acuity decreased to 20/70 OD with increased right orbital congestion, exophthalmos (25 mm OD and 21 mm OS [left eye]), and worsening limitation of ductions OD. magnetic resonance imaging/magnetic resonance angiography of her head demonstrated fusiform dilatation of the cavernous segment of the right internal carotid artery (ICA) with asymmetrical enhancement of the right cavernous sinus and an enlarged right superior ophthalmic vein (SOV) consistent with arterialized flow from a carotid-cavernous fistula (CCF).The patient was urgently referred to neuro-interventional radiology for diagnostic angiography and embolization of the CCF. The cerebral angiogram showed a right direct (Barrow type A) CCF, with rapid enhancement of the right cavernous sinus and right SOV. 7-mm fusiform aneurysm of the right cavernous ICA was found to be the likely cause of the CCF (Figure 1A). Transarterial access of the fistula for coil embolization was unsuccessful.Figure 1. A , Pretreatment digital subtraction angiography, lateral magnified view, right common carotid artery injection, showing early, rapid opacification of the right cavernous sinus (black arrow) and right superior ophthalmic vein (white arrows) consistent with a direct carotid-cavernous fistula. There is also fusiform dilatation of the cavernous right internal carotid artery representing dysplasia with an aneurysm. B , Photograph showing the direct access provided to the right superior ophthalmic vein for coil embolization. C , …