Compressive Optic Neuropathy Caused by Internal Carotid Artery Aneurysm Presenting with Concurrent Neuromyelitis Optica

Abstract

Purpose: To report a case of compressive optic neuropathy caused by an internal carotid artery aneurysm accompanied by concurrent neuromyelitis optica (NMO).Case summary: A 48-year-old female presented with sudden painless blurry vision in the inferior visual field of her right eye for 2 days. The corrected visual acuity was 0.7 in the right eye, and a relative afferent pupillary defect was observed. The visual field test demonstrated an inferior altitudinal defect in the right eye, while the color vision test was normal. However, after 5 days, she developed decreased color vision. Optic nerve enhancement in the right eye was observed on orbital magnetic resonance imaging, and anti-aquaporin-4 antibody was positive. She was diagnosed with NMO, and high-dose steroids were administered intravenously. In addition, brain magnetic resonance angiography showed a 5-mm aneurysm in the ophthalmic segment of the right internal carotid artery, which was compressing the optic nerve. Coil embolization of the aneurysm was performed. On the fourth day of steroid therapy and the first day after coiling, the corrected visual acuity in the right eye improved to 1.0. At 6-week follow-up, color vision and visual field defect also showed complete recovery.Conclusions: In this rare case of internal carotid artery aneurysm combined with NMO, early active treatment led to complete recovery of visual acuity and field defects.