Episode 106. Toxic Alcohols with Thom Maciulewicz

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Show Notes from the Pharm So Hard Podcast with Dr. Thom MaciulewiczOverviewToxic alcohols like methanol, ethylene glycol, and isopropanol can cause severe metabolic acidosis and organ damage when ingested. This post summarizes key learnings from a podcast episode with toxicology expert Dr. Thom Maciulewicz on recognizing and managing toxic alcohol poisoning in the emergency setting.Key Topics Covered:

• What are toxic alcohols?
• Clinical signs and symptoms
• Metabolic pathways
• Diagnostic approach
• Treatment principles
• Specific agents – methanol, ethylene glycol, isopropanol
• Importance of history taking
• Using antidotes – fomepizole vs ethanol
• Determining need for hemodialysis
• Supportive care and monitoring

What are Toxic Alcohols?

• Substances like methanol, ethylene glycol, isopropanol
• Found in antifreeze, windshield fluid, solvents, fuels
• NOT meant for human consumption
• Metabolize into toxic intermediates

Clinical Presentation

• CNS: Confusion, ataxia, coma
• GI: Nausea, vomiting, pain
• Ocular: Vision changes, blindness
• Renal: Flank pain, kidney injury
• Cardiac: Tachycardia, hypotension
• Metabolic: High anion gap acidosis

Metabolic Pathways

• Alcohol dehydrogenase converts parent alcohol into toxic aldehydes and acids
• Methanol -> formaldehyde -> formic acid
• Ethylene glycol -> metabolites like glycolic acid and oxalic acid
• Isopropanol -> acetone
• Organic acids cause high anion gap metabolic acidosis

Diagnostic Approach

• Clinical suspicion from history and exam
• High anion gap metabolic acidosis
• Check osmolal gap, electrolytes, renal function
• Test specific alcohol levels
• Assess for end-organ damage like vision changes or kidney injury

Treatment Principles

• IV fluids for hydration support
• Bicarb for severe acidemia
• Fomepizole or ethanol to block alcohol dehydrogenase
• Hemodialysis to clear parent compound and metabolites
• Manage end-organ effects – folinic acid for methanol, thiamine/pyridoxine for ethylene glycol
• Close monitoring and supportive care

Specific AgentsMethanol

• Formic acid causes blindness and basal ganglia damage
• Bicarb, fomepizole, folinic acid
• Hemodialysis often needed

Ethylene Glycol

• Oxalic acid crystals cause kidney injury
• Bicarb, fomepizole, thiamine, pyridoxine
• Hemodialysis if renal failure

Isopropanol

• Acetone causes CNS depression
• Supportive care, address gastritis
• Hemodialysis rarely needed

Key Takeaways

• Obtain thorough history – critical for identifying possible toxic alcohol exposure
• Have low threshold to start fomepizole empirically if concerned
• Tailor management to likely toxicant – methanol, ethylene glycol, isopropanol have important distinctions
• Determine need for hemodialysis since it is definitive treatment for significant poisoning
• Provide diligent monitoring and supportive care throughout course

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