Ethylene Glycol Intoxication
7/11/10
PY Mindmaps
- 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
- toxic dose = 1.5mL/kg of 95% ethylene glycol
INVESTIGATIONS
- ethylene glycol level
- 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 easily 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
- thamine 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
Jeremy Fernando (2011)
HTTPSTAFFTUHSDK12AZUSGFOSTERSTANDARDBGRAPH6HTM GRAPHING PRACTICE PROBLEM 1 AMOUNT OF ETHYLENE IN
LOW VELOCITY IMPACT ON LAMINATES REINFORCED WITH POLYETHYLENE AND
MONARFLEX RAC GAS MEMBRANE 140A LOOSE LAID POLYETHYLENE GAS
Tags: mindmaps, ethylene, relatively, glycol, nontoxic, intoxication, 71110