Arteriovenous anomalies — carotid-cavernous fistula

A 53-year-old Caucasian male presented with six weeks of acute-onset painless binocular vertical diplopia. He then developed proptosis, lid edema, redness, and a pulsatile sensation in the right eye (OD). His past medical history was significant only for medication-controlled hyperlipidemia, and he denied a history of hypertension, diabetes, or trauma. The remainder of his medical history was unremarkable. On examination, he had moderate lower lid edema OD but no lid retraction or lid lag. Hertel measurements showed 5 mm of proptosis OD. His best-corrected visual acuity was 20/20 in both eyes (OU). The pupillary exam was normal and there was no relative afferent pupillary defect (RAPD). Extraocular movements showed slight adduction and elevation deficits OD. There was a moderate right exotropia and right hypertropia that was worse on right head tilt. The intraocular pressure was 20 mmHg OD and 15 mmHg in the left eye (OS). Markedly pulsatile and wide mires were noted OD as compared to normal applanation mires OS. Slit lamp examination showed arterialized, tortuous, and dilated conjunctival vessels extending to the limbus OD (see Fig. 15.1), but biomicroscopy was normal OS. Dilated funduscopic exam showed mildly dilated veins OD but was otherwise normal OU. Automated visual fields (Humphrey 24-2) were normal OU. Magnetic resonance imaging (MRI) of the brain and orbits with and without gadolinium with fat suppression demonstrated an enlarged right superior ophthalmic vein (SOV) and inferior ophthalmic vein with arterial flow voids present in these normally slow-flow veins (see Fig. 15.2). A cerebral catheter angiogram showed an indirect dural arteriovenous (AV) fistula of the right cavernous sinus supplied by branches of the internal and external carotid arteries (see Fig. 15.3).