Carotid cavernous fistula with central retinal artery occlusion and Terson syndrome after mid-facial trauma

Visual impairment in high flow and low flow carotid cavernous fistula

Our aim is to study the varied posterior segment manifestations, level of visual impairment (VI) and its causes in carotid cavernous fistula (CCF) patients. A retrospective study was done, wherein data was obtained from 48 digital subtraction angiogram (DSA) proven CCF patients. CCF was classified according to Barrow et al., based on DSA into type A (high flow) and types B, C and D (low flow). High flow CCF was present in 8 (16.7%) and low flow CCF was present in 42 (83.3%). Compared to low flow group, patients in high flow group were younger and had a history of trauma (p < 0.05). Posterior segment findings ranged from familiar stasis retinopathy and optic neuropathy (both, glaucomatous and ischemic) to uncommon findings of central retinal artery occlusion, Terson syndrome and combined retinal and choroidal detachment. Retinal vein dilatation was the most common finding in both groups. The high flow CCF group had 6 (75%) patients that had VI. This was acute in 4 (50%) patients and delayed in 2 (25%). In the low flow group 10 (23.8%) of patients had delayed VI. The identification of "3 point sign" is a novel finding of this study, not described before. While none of three findings (disc hyperaemia, retinal vein dilatation and intra-retinal haemorrhage) in isolation were predictive of visual loss, but when present together results in visual loss. Posterior segment changes were varied, some are uncommon and can occur in various combinations. "3 point sign" must be identified at the earliest to prevent visual impairment. The incidence of VI in CCF patients is high.

Sudden-onset Blindness from a Spontaneous Carotid-cavernous Fistula with Secondary Central Retinal Artery Occlusion and Posterior Ischemic Optic Neuropathy

Our case describes a patient diagnosed with a carotid-cavernous fistula (CCF) secondary to a spontaneously ruptured cavernous carotid aneurysm, presenting with sudden vision loss, and a concomitant central retinal artery occlusion as visualized by a cherry-red spot in the macula and posterior ischemic optic neuropathy. Computed tomography of the brain and orbits showed mild hydrocephalus, orbital fat haziness, and proptosis with concern for fluid in the basal cisterns. Cerebral angiography confirmed the suspected diagnosis of CCF. After angiography, a Magnetic resonance imaging of the brain demonstrated abnormal diffusion restriction in the posterior right optic nerve confirmed on the apparent diffusion coefficient map, consistent with ischemia of the optic nerve in this location. Two weeks after discharge, outpatient fundus photography showed resolution of her cherry-red spot, and optical coherence tomography showed thinning of the entire retinal nerve fiber layer as compared to the contralateral eye. In CCFs, congestive symptoms of proptosis, pain, and even central retinal vein occlusion findings are frequently described. However, our patient's no light perception vision and imaging findings suggest associated central retinal artery occlusion and ischemic optic neuropathy. These findings underscore the multitude of serious visual effects of high flow CCFs.