Morning Report: Ethylene Glycol Toxicity

Thanks to Dr. Rolston-Cregler for today’s Morning Report!

Ethylene Glycol Toxicity

The Basics

Toxic Alcohol with the chemical structure C2H6O2
Main ingredient in antifreeze
Sweet taste often attracts children and animals

Clinical Presentation

Altered mental status
Dyspnea may be a manifestation of underlying metabolic acidosis

Laboratory Findings

Early findings include an osmolar gap
Followed by a high anion gap metabolic acidosis

Calculation of Levels

Most laboratory assays are send outs and not helpful in a timeframe that will benefit the patient

Osmolar Gap = calculated osmolality – serum osmolality

If no other alcohol ingestions, level can be estimated by multiplying osmolar gap X 6.2

(Molecular weight of 62 g/mol)

Metabolism Pathway

http://www.cjem-online.ca/sites/cjem-online.ca/files/image/034-f2.gif

Interventions

Fomepizole or 4MP – competitively inhibits alcohol dehydrogenase

slows the reduction of toxic metabolites
inhibits deposition of oxalic acid in tissues
15 mg/kg over 30 minutes

Ethanol

can be given oral or parenteral
loading dose followed by continuous infusion to maintain a level of 100 mg/dL
- loading dose of 10 ml/kg in 10% ethanol solution of D5W given over 60 minutes should raise serum concentration by 100 mg/dL
- maintenance infusion of the same solution should start at 1 ml/kg/hr and be titrated to the desired concentration, Q1-2 hour recheck of levels
can be difficult to titrate
frequent fingersticks due to potential hypoglycemia

Thiamine & Pyridoxine: administration of co-factors can shunt reactions away from the major pathway and result in the production of less oxalic acid, the main toxic metabolite of glycolic acid pathway

Dialysis

used to treat metabolic acidosis and to prevent renal insufficiency
once oxalate has begun to deposit in tissues must be used in conjunction with fomepizole to remove parent compound as well as metabolites

Threshold for Therapy

– Arterial pH less than 7.3

– Serum bicarbonate level less than 20 mg/dL

– Osmol gap greater than 10 mOsm/L

– Oxalate crystals in the urine

– Ethylene glycol level > 20

References: