Ethylene glycol
Summary
Sweet-tasting antifreeze component metabolized by alcohol dehydrogenase to glycolic and oxalic acids, causing high anion-gap metabolic acidosis and acute kidney injury with calcium oxalate crystals.
Detail
Ethylene glycol is metabolized by alcohol dehydrogenase to glycolaldehyde, then to glycolic acid and oxalic acid; the latter binds calcium to form calcium oxalate crystals that deposit in renal tubules, causing acute tubular necrosis and hypocalcemia. Presentation: inebriation without alcohol odor, high anion-gap metabolic acidosis with elevated osmolar gap, flank pain, oliguric AKI, and tetany. Urinalysis: envelope-shaped (monohydrate, needle-like) calcium oxalate crystals; urine may fluoresce under Wood's lamp (added fluorescein in antifreeze). Treatment: fomepizole (preferred, inhibits alcohol dehydrogenase) or ethanol; hemodialysis for severe acidosis or renal failure. Classic boards: child or alcoholic with sweet-tasting drink + crystalluria + AKI.
Sources
- First Aid for USMLE Step 1 2024
- Goljan Rapid Review Pathology
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