Bilateral Putaminal and Optical Involvement After Low Dose of Methanol Exposure: Case Report

Methanol is a toxin with rare but serious effects on the central nervous system. It may cause severe visual dysfunction and mortality. This study presents the case of a 44-year-old man admitted to our clinic with bilateral amaurosis which developed after dental intervention for gingivitis. The patient was conscious and presented with stomach ache, nausea, vomiting, weakness, imbalance, and bilateral amaurosis; methanol poisoning was diagnosed. Upon examination, the absence of light perception in the eye and bilateral weakness in light reflexes were detected. Visually-evoked potentials (P100) could not be obtained. Hyper-intense lesions with bilateral putaminal localisation were observed on magnetic resonance imaging and bilateral pupil oedema was observed by fundus photography. The patient was treated with methyl prednisolone and intravenous vitamin B1. On the fifth day after admission, fluctuations in visual findings were observed, and light reflex loss and pupillary dilatation developed. Upon examination one and six months later, bilateral (total) amaurosis and bilateral optic atrophy were detected. This case demonstrates bilateral putaminal involvement after exposure to a very low dose of methanol.