[A case of methanol intoxication with optic neuropathy visualized on STIR sequence of MR images]

We report a 24-year-old man with severe methanol intoxication, who showed cerebral and optic nerve damages on MRI. He was admitted to our hospital with an acute onset of unconsciousness and severe metabolic acidosis, and was immediately treated by hemodialysis. His serum methanol concentration was 261.5 mg/dl. Although this methanol concentration was lethal, he was rescued by intensive care. Three days after admission, brain MRI was performed. Diffusion weighted images showed abnormal hyperintensities in bilateral putamina, subcortical white matter and cerebellar hemispheres. STIR sequence revealed bilateral optic nerve swelling with irregular hyperintense rims. These MRI features might reflect the optic nerve damages, mainly demyelination of the optic nerves caused by a myelinoclastic effect of formic acid, a metabolite of methanol.