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

References and Links


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

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

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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