The mystery of the vision and its silent killer: A case report of optic neuropathy due to carbon monoxide poisoning

Abstract

We report a case of a young, healthy male with sudden neurological collapse in the bathroom, presenting 3 weeks later with bilateral progressive dimunition of vision. Patient’s initial investigations including computed tomography (CT) brain was normal. At the time of presentation, he had severe visual impairment with defective colour vision and disc pallor bilaterally. Magnetic resonance imaging (MRI) brain was suggestive of carbon monoxide (CO) poisoning. A visual evoked potential (VEP) showed characteristic positive-negative-positive (PNP) waveform. Retrospective history confirmed the use of gas geysers in his bathroom. Patient was treated with intravenous steroids for 3 days followed by oral steroids to which he responded with improvement in visual acuity. Parenteral vitamin B12 was also administered. Optic neuropathy is a rare presentation of CO poisoning with very few cases reported in literature.