Unexplained drowsiness and progressive visual loss: Methanol poisoning diagnosed at autopsy

A patient was admitted to the emergency department with a reduced level of consciousness and deteriorating vision. Her pupils became fixed and dilated and she developed a third nerve palsy with extensor posturing of her limbs. Biochemistry profile showed an increased serum osmolar gap with a raised anion gap metabolic acidosis. Supportive treatment was instituted, but she made no recovery and brainstem death was later confirmed. Post mortem examination and toxicology screen confirmed the cause of death as methanol poisoning leading to cerebral oedema and transtentorial herniation. We highlight some of the diagnostic difficulties associated with treating a patient with a reduced level of consciousness. The clinical and biochemical findings that are critical in establishing a diagnosis of methanol intoxication are discussed. The definitive management of methanol poisoning is reviewed.