Retinal arteriovenous malformation (AVM) is a rare congenital vascular anomaly characterized by marked arterial and venous dilatation with an aberrant-to-absent capillary bed. The presentation ranges from small anastomotic communications scarcely visible on ophthalmoscopy to pronounced dilatations of the entire retinal vascular system.1 We present a photo essay of a unilateral AVM in a 16-year-old girl associated with bilateral optic nerve drusen (OND), complicated with impending vein occlusion.
Ultra-widefield retinography in the left eye (OS) showed macular macrovessels crossing the horizontal raphe and rare hemorrhages in the inferotemporal periphery (Figure 1A). The right eye (OD) featured no vascular anomalies. Fundus autofluorescence revealed hyperautofluorescence at the optic nerve head in both eyes (Figure 1B). Optical coherence tomography (OCT) showed irregularity in subfoveal ellipsoid zone and external limiting membrane OS, along with mild disorganization of inner retinal layers (Figure 1C). Ultra-widefield fluorescein angiography (UWFA) and OCT angiography showed engorged vascular loops, scattered microaneurysms, partially obliterated foveal avascular zone with macular-foveal capillaries, and areas of capillary dropout (Figures 1D and 1E). The patient was diagnosed with bilateral OND and AVM-related impending vein occlusion OS.
Multimodal imaging of arteriovenous malformation and optic nerve drusen. (A) Ultra-widefield (UWF) retinography showing dilated and tortuous vessels in the inferotemporal branch and rare hemorrhages (arrow); optic nerve head contours are blurred. (B) Fundus autofluorescence showing optic disc multiple, rounded hyperautofluorescent lesions (asterisk). (C) Optical coherence tomography highlights subfoveal irregularity in the outer retinal layers (arrowhead). A dilated vessel is seen nasally with slight tenting of the internal limiting membrane (arrow). (D) UWF fluorescein angiography reveals vascular loops, arteriovenous connections, and inferotemporal capillary drop-out. In the macular area, some macular-foveal capillaries are noticeable (detail). No late-phase leakage or epiretinal neovascularization is seen. (E) Optical coherence tomography angiography showing the abnormal capillary bed and focal areas of nonperfusion in the inferotemporal retina.
Vein occlusion remains the most common complication in AVMs: increased intravascular pressure and high, turbulent flow lead to endothelial damage, and fibrosis of vessel walls.2,3 As per Virchow's triade, the coagulative cascade may be triggered. OND are also a known risk factor for retinal vascular occlusion, as they cause mechanical compression at the lamina cribrosa, elevating central retinal venous pressure. Enlargement of drusen volume, which typically occurs in teenagers, might have precipitated the impaired perfusion state, leading to clinically significant flow obstruction.4
The co-existence of AVM and OND in a patient with suspected Wyburn-Mason syndrome is a novel description. Such association has been described in Klippel-Trenaunay syndrome.5 The presence of both AVM and OND might have an additive effect on the likelihood of vascular events to occur.
- Mansour AM, Walsh JB, Henkind P. Arteriovenous anastomoses of the retina. Ophthalmology. 1987;94(1):35–40. doi:10.1016/S0161-6420(87)33505-5 [CrossRef] PMID:3561955
- Callahan AB, Skondra D, Krzystolik M, Yonekawa Y, Eliott D. Wyburn-Mason Syndrome Associated with Cutaneous Reactive Angiomatosis and Central Retinal Vein Occlusion. Ophthalmic Surg Lasers Imaging Retina. 2015;46(7):760–762. doi:10.3928/23258160-20150730-12 [CrossRef] PMID: 26247458
- Salati C, Ferrari E, Basile R, Virgili G, Menchini U. Retinal vein occlusion: late complication of a congenital arteriovenous anomaly. Ophthalmologica. 2002;216(2):151–152. doi:10.1159/000048316 [CrossRef] PMID:11919443
- Malmqvist L, Lund-Andersen H, Hamann S. Long-term evolution of superficial optic disc drusen. Acta Ophthalmol. 2017;95(4):352–356. doi:10.1111/aos.13315 [CrossRef] PMID:27996202
- Bothun ED, Kao T, Guo Y, Christiansen SP. Bilateral optic nerve drusen and gliomas in Klippel-Trenaunay syndrome. J AAPOS. 2011;15(1):77–79. doi:10.1016/j.jaapos.2010.10.009 [CrossRef] PMID:21315629