Unilateral asymptomatic optic disc edema: do not forget sinusitis

Abstract

Background: Optic disc edema is a pathological condition with various causes. Cases of optic disc swelling should be dealt with a multidisciplinary approach to rule out those causes. Unilateral optic disc edema is seen in papillitis, non-arteritic anterior ischemic optic neuropathy, retinal vein occlusion, and infection or inflammation of the contiguous sinus or orbit. Here, we report a rare case of unilateral asymptomatic optic disc edema due to posterior ethmoid sinusitis. 
 Case Presentation: A 53-year-old man presented for a routine 3-monthly follow-up after an uneventful cataract surgery of the right eye. All examinations were unremarkable, except for the right eye optic disc edema on fundus examination, consistent with an enlarged blind spot in the visual field test. Contrast-enhanced magnetic resonance imaging revealed mucosal thickening with muco-inflammatory exudates of the posterior ethmoidal sinus overriding the optic disc on the right side, leading to optic disc edema of the right eye. The patient was diagnosed with unilateral asymptomatic optic disc edema in the right eye due to posterior ethmoid sinusitis and referred to an otorhinolaryngologist for the management. The otorhinolaryngologist performed functional endoscopic sinus surgery and prescribed antibiotics and anti-histamines for 6 weeks. At the final examination, his visual acuity was 6/6, and the fundus examination revealed no optic disc edema.
 Conclusions: We reported a rare case of unilateral optic nerve edema and visual field loss with a treatable cause. Contemporary imaging provided the accurate diagnosis. Therefore, in cases of disc edema, sinusitis of the adjacent paranasal sinuses should be ruled out as a possible cause of compressive optic neuropathy or inflammation overriding the optic nerve.