Differentiation of Suspected Methanol Poisoning From Ethanol Poisoning: A Review Study and Consensus Statement

Abstract

Background: Ethanol and methanol poisoning pose significant clinical challenges due to their overlapping clinical presentations. This literature review and consensus statement aim to provide evidence-based guidelines for differentiating these two poisonings.Methods: We conducted a comprehensive literature review of relevant literature, including individual patient data (IPD) meta-analysis, to assess clinical, laboratory, and diagnostic findings in cases with ethanol and methanol poisoning. A literature review was also performed to gather case series of electrocardiograms of ethanol and methanol poisoning. We synthesized the evidence and convened an expert panel to develop consensus-based recommendations.Results: Based on the literature review and IPD analysis, cases of methanol poisoning often present later than 24 hours after alcohol consumption, emphasizing the importance of assessing patients with delayed referrals. Methanol-poisoned patients are frequently awake and responsive after 12 hours of ingestion, but symptoms alone do not reliably differentiate between the two poisonings. Declines in visual acuity and symptoms are strongly associated with methanol poisoning and should prompt immediate hospitalization and ophthalmic examination. Oliguria and anuria are more common in cases of methanol poisoning, warranting detailed urinary symptom assessment and close monitoring of urinary output. Electrocardiograms are essential for all alcohol poisoning patients, with non-sinus rhythm suggesting methanol poisoning. Arterial blood gas analysis, with low pH values, favors methanol poisoning. However, blood sugar levels alone cannot definitively determine the type of poisoning. Laboratory point-of-care tests to diagnose methanol in serum are urgently needed.Conclusion: This literature review and consensus statement offer guidance for healthcare providers facing cases of alcohol poisoning where point-of-care testing methods of blood alcohol concentrations are unavailable. A comprehensive assessment, considering clinical history, physical examination, laboratory data, and specialized evaluations such as ophthalmic examination and electrocardiograms, is essential for accurately differentiating ethanol and methanol poisoning.