Ethylene Glycol & Methanol Poisoning

Key points

• Ethylene glycol (antifreeze) → glycolic/oxalic acid: high anion gap metabolic acidosis, calcium oxalate crystals in urine, hypocalcaemia, renal failure.
• Methanol → formic acid: high anion gap acidosis + visual disturbance ('snowfield' vision), blindness.
• Both cause high osmolar gap early, high anion gap later.
• Treatment: fomepizole (alcohol dehydrogenase inhibitor) or ethanol + haemodialysis if severe.
• Give cofactors: folinic acid (methanol), thiamine/pyridoxine (ethylene glycol).

Decision points in this pathway

• Which alcohol?
• Severe acidosis/end-organ damage?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.