What are stages of ethylene glycol (EG) toxicity?

Updated: Dec 05, 2017
  • Author: Daniel C Keyes, MD, MPH; Chief Editor: Sage W Wiener, MD  more...
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Answer

Initially, patients may be asymptomatic, but ethylene glycol is rapidly absorbed (within 1 to 4 hours), and altered mental status and tachypnea then begin to appear as the ethylene glycol is successively metabolized to very toxic compounds. The progression of toxic effects can be roughly divided into the following three stages, although overlap is possible [1] :

  • From 30 minutes to 12 hours after exposure, unmetabolized ethylene glycol produces CNS depression, intoxication, and hyperosmolarity similar to that produced by ethanol.
  • From 12 to 48 hours, ethylene glycol metabolites produce severe anion gap metabolic acidosis with compensatory hyperventilation. The acidosis results primarily from an increase in glycolic acid, although glyoxylic, oxalic, and lactic acids also contribute in small part. Calcium oxalate crystals are deposited in the brain, lungs, kidneys, and heart.
  • From 24 to 72 hours, acute kidney injury.can result from the direct renal toxic effects of the ethylene glycol metabolite calcium oxylate monohydrate.

Initial treatment includes infusion of crystalloids to enhance renal clearance of the toxic metabolites. Ethyl alcohol has traditionally been used for antidotal treatment, but it has largely been supplanted by fomepizole in the United States.


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