Acute methanol poisoning

Case contributed by Ashesh Ishwarlal Ranchod


Acute onset of blindness, headache, and sudden collapse

Patient Data

Age: 30 years
Gender: Male

There is bilateral, symmetric, acute non-hemorrhagic putaminal necrosis with restricted diffusion and associated reduced average diffusivity on corresponding ADC mapping.

There is no abnormal enhancement post-contrast administration.

There is bi-frontal cortical restriction additionally.

Important negatives include normal optic nerves, optic pathway, occipital lobes, normal subcortical and deep white matter, and normal cerebellar hemispheres.

MRI brain is otherwise unremarkable.

Case Discussion

This patient has acute methanol poisoning based on imaging with biochemical corroboration.

Methanol is a highly toxic liquid not intended for human consumption.

There was no background history of parasuicide.

The patient responded poorly to active management to reduce the methanol levels and correct the metabolic acidosis and subsequently died.

Standard treatment involves the use of intravenous ethanol in an attempt to reduce the production of formate. Methanol is first metabolized into formaldehyde by alcohol dehydrogenase. Formaldehyde is metabolized into formic acid (formate) by aldehyde dehydrogenase.

The patient's methanol and urine formic acid levels were significantly elevated confirming methanol poisoning; urine formic acid: 15,153 mg/gCr (non-industrial exposure: 0.0-23.0 mg/gCr) (formic acid urine concentrations usually expressed as grams per grams of creatinine) and urine methanol: 7589.65 mg/L (normal range: 0.00-2.00 mg/L)

The patient's toxic screen was otherwise negative, specifically no evidence of carbon monoxide poisoning, cyanide toxicity was considered less likely due to poor accessibility to cyanide in general and organophosphate poisoning was also excluded.

The complete drug screen was negative and SARS-CoV-2 RT-PCR and rapid antigen tests were negative.

There was poor antecedent history and the exact nature of toxic ingestion could not be proven (accidental/ voluntary/involuntary (or forced) ingestion of methanol containing industrial solvent/liquid or the consumption of homemade alcohol.

During the early stages of the COVID-19 pandemic, there has been an increased incidence of homemade alcohol production and consumption when hard lockdowns banned the purchase of alcohol in South Africa.

In this instance, the extremely high level of methanol suggested likely industrial solvent ingestion.

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