EM · Toxicology and environmental emergencies

Toxic alcohol poisoning (methanol and ethylene glycol)

Also known as Methanol poisoning · Ethylene glycol poisoning · Antifreeze poisoning · Windshield washer fluid ingestion · Toxic alcohol ingestion

Toxic alcohol poisoning — methanol (windshield washer, illicit spirits) and ethylene glycol (antifreeze) are small alcohols metabolised by alcohol dehydrogenase to the acids that do the harm: methanol to formaldehyde then formic acid (the blindness, the putaminal necrosis on CT, the high anion gap metabolic acidosis), ethylene glycol to glycolic acid and oxalic acid (the calcium oxalate crystals in the urine, the acute kidney injury). The bedside signature is a high anion gap metabolic acidosis paired with an elevated osmolar gap. Management is alcohol dehydrogenase blockade with fomepizole 15 mg/kg IV loading then 10 mg/kg every 12 hours (or 10 per cent ethanol at 10 mL/kg bolus then 1 to 2 mL/kg/h as the cheaper alternative), cofactors (folinic acid 1 mg/kg for methanol; thiamine and pyridoxine for ethylene glycol), and haemodialysis for the severe case. The differential is the high anion gap metabolic acidosis: lactic acidosis, DKA, salicylate, uraemia. ACEM-primary, globally tagged.