Ethanol, methanol and ethylene glycol poisoning

1. Big picture

Ethanol, methanol, and ethylene glycol are alcohols, but their danger is different:

• Ethanol mainly causes central nervous system depression, hypoglycemia, aspiration, trauma, hypothermia, and sometimes alcoholic ketoacidosis.
• Methanol is dangerous because it is metabolized to formic acid, causing high anion gap metabolic acidosis + visual toxicity.
• Ethylene glycol is dangerous because it is metabolized to glycolic and oxalic acids, causing high anion gap metabolic acidosis + acute kidney injury + calcium oxalate crystals.

The exam pattern is simple:

Drunk-looking patient + high osmol gap early + high anion gap metabolic acidosis later = toxic alcohol until proven otherwise.

For methanol and ethylene glycol, the life-saving principle is: Block alcohol dehydrogenase early with fomepizole or ethanol, correct acidosis, and dialyze if severe.

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