Ethylene Glycol Toxicity

OVERVIEW

  • >1 mL/kg or a mouthful in a child is potentially lethal
  • ethylene glycol itself is relatively non-toxic -> metabolites extremely toxic (glycolate)
  • rate limiting step = alcohol dehydrogenase activity
  • accumulation of glycolate -> direct cellular toxicity

CLINICAL FEATURES

  • drunk: automotive antifreeze, solvent, polish, paints, cosmetics, brake fluid, car wash fluid.
  • 30 minutes -> 12 hours post ingestion:excitement, confusion, disorientation -> ataxia, lethargy, stupor, coma, nausea/vomiting, myoclonus, seizures, cranial nerve deficits: nystagmus, ophthalmoplegia, facial palsy, dysarthria, dysphagia
  • 12 – 24 hours: progressive cardiorespiratory failure
  • 24 – 72 hours: renal failure from ATN

INVESTIGATIONS

  • ethylene glycol level (rarely useful acutely due to delays in obtaining result)
  • severe metabolic acidosis (high anion gap) from glycolic acid accumulation
  • very high lactate (artefactual as there is high cross reactivity between lactate and glycolate in laboratory analysis) -> high lactate with oxidase method, less high with lactate dehydrogenase method
  • high osmolar gap
  • calcium oxalate crystalluria (oxalate produced by ethylene glycol metabolism chelates Ca2+ -> formation of crystals) + hypocalcaemia
  • fluorescence of urine on exposure to UV light (automotive antifreeze solutions have this to identify cooling system leaks)

MANAGEMENT

  • goal = blockade of alcohol dehydrogenase -> so ethylene glycol isn’t converted to glycolate
  • decrease absorption: no techniques really effective
  • decrease production of toxic metabolites: ethanol or 4-methylpyrazole (not available in Australiasia)

-> ethanol dose (IV): 10% solution in D5W as a 40% solution, loading dose 7.5mL/kg -> 1-2mL/kg/hr
-> ethanol dose (PO): quarter the above dose
-> dose in CRRT: double IV dose
-> maintain ethanol level @ 25-40mmol/L

  • haemodialysis
  • thiamine 100mg IV Q6 hrly – theoretical benefit to increase elimination
  • pyridoxine (vitamin B6) 50mg IV Q6hrly – theoretical benefit to increase elimination
  • don’t replace Ca2+ unless low enough to cause manifestations

CCC Toxicology Series

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.