Toxic Alcohol Ingestion
Summary Table
| Ethylene Glycol | Methanol | Isopropyl Alcohol | |
|---|---|---|---|
| Source | Antifreeze, wiper fluids, fuels | moonshine | |
| Signs and symptoms | Decreased LOC, hematuria, flank pain, oliguria, hypocalcemia | Decreased LOC, retinal injury and blindness | |
| Physical examination | CN palsies | Afferent pupillary defect, mydriasis, retinal sheen, optic disc hyperemia | |
| Labs | High AG and OG, hypocalcemia and long QTc | High AG and OG | High OG, normal AG, ketoacidosis |
Osmolar gap
$$\textrm{Osmolar gap} = Serum_{osm} - Calc_{osm}$$
$$Calc_{osm} = (2 \times Na) + Glucose + BUN + (1.25 \times EtOH)$$
Lack of osmolar gap does not rule out toxic alcohol ingestion. This is due to the conversion of parent alcohol over time to anions:
Differential by AG and OG
| High OG | Normal OG | |
|---|---|---|
| High AG | Ethylene glycol, Methanol, ketoacidosis, propylene glycol, ESRD | MUDPILES, late toxic alcohol presentation |
| Normal AG | Isopropyl alcohol, ethanol, severe hyperproteinemia/hyperlipidemia, early toxic alcohol presentation | n/a |
Treatment of Toxic Alcohols
In general: ABCs, IV, O2, Foley, monitored setting. Consider:
- Decontamination: generally no role, can try NG aspiration if within 60 minutes
- Enhanced elimination: treat acidemia as this increases tissue penetration.
- NaHCO3 1-2 mEq/kg then infusion at 150-250 cc/hr. Goal pH = 7.35
- Hemodialysis is the definitive therapy and will clear the alcohol and its toxic metabolite. Indications for HD: HAGMA + evidence of end-organ damage
- Specific antidote: inhibition of AlcDH which prevents degradation of parent alcohol into toxic metabolites. Options are fomepizole or EtOH.
- Indications:
- serum methanol > 6.2 mM or ethylene glycol >3.2 mM, OR
- documented recent history of toxic amounts of methanol or ethylene glycol, and OG > 10, OR
- Suspicion of ingestion and 2 of the following:
- pH < 7.3 OR bicarb <20 OR OG > 10 OR urine oxalate crystals
- Indications:
Isopropyl alcohol: supportive treatment only. Metabolized to acetone (as is acetacetate). Mainly manifests as gastrointestinal and neurologic effects.