Ethylene Glycol Poisoning Treatment Guidelines
Immediate Antidote Therapy
- The American College of Medical Toxicology recommends immediately administering fomepizole (15 mg/kg loading dose) upon suspicion of ethylene glycol poisoning, and initiating hemodialysis if the patient presents with severe metabolic acidosis, coma, seizures, acute kidney injury, or ethylene glycol concentration ≥50 mg/dL 1, 2
- Ethanol can be used as an alternative to fomepizole if it is unavailable, but requires careful monitoring to maintain therapeutic levels (100-150 mg/dL) 1
Extracorporeal Treatment (Hemodialysis) Indications
- Hemodialysis is strongly recommended when any of the following criteria are met: anion gap >27 mmol/L, coma, seizures, acute kidney injury (KDIGO stage 2 or 3), or ethylene glycol concentration ≥50 mg/dL 1, 2
- The EXTRIP guidelines recommend hemodialysis for patients with anion gap >27 mmol/L, glycolate concentration >12 mmol/L, or ethylene glycol concentration ≥50 mg/dL 1, 2
- Chronic kidney disease with eGFR <45 mL/min/1.73m² is a conditional recommendation for hemodialysis 1, 2
Hemodialysis Technical Considerations
- Intermittent hemodialysis is the preferred modality for removing ethylene glycol and metabolites, and correcting acidemia faster 1, 3
- Continuous kidney replacement therapy (CKRT) is the second-line option if intermittent hemodialysis is unavailable or if the patient has marked brain edema 1, 3
- Hemodialysis should be stopped when the anion gap is <18 mmol/L, ethylene glycol concentration is <4 mmol/L (25 mg/dL), or acid-base abnormalities are corrected 1, 3
Critical Pitfalls to Avoid
- The American College of Medical Toxicology recommends not relying solely on reported ethylene glycol dose for treatment decisions, as anion gap only predicts the need for hemodialysis if high pre-test probability of ethylene glycol exposure exists 1, 2
- Anion gap may overestimate glycolate or underestimate it, and ethylene glycol concentrations diminish as metabolites accumulate, so both parent compound and acid-base status must guide treatment 3
- Monitor for alcohol withdrawal in patients with alcohol use disorder, especially during hemodialysis 4
Ethylene Glycol Poisoning Management
Immediate Antidote Therapy
- Ethanol can be used as an alternative alcohol dehydrogenase inhibitor, but requires careful monitoring to maintain therapeutic levels, as recommended by the American Association of Poison Control Centers 5, 6
Extracorporeal Treatment (Hemodialysis) Indications
- Hemodialysis is strongly recommended when glycolate concentration >12 mmol/L, anion gap >27 mmol/L, coma or seizures, Stage 2 or 3 acute kidney injury, significant or worsening metabolic acidosis, or ethylene glycol concentration ≥50 mg/dL, according to the American College of Medical Toxicology 5, 6, 7, 8
- The American Society of Nephrology recommends hemodialysis for patients with ethylene glycol poisoning who have anion gap >27 mmol/L or glycolate concentration >12 mmol/L 5, 8
Hemodialysis Technical Considerations
- Intermittent hemodialysis is the preferred modality, with continuous kidney replacement therapy as an alternative, as suggested by the European Renal Association 5
- The American College of Physicians recommends adjusting fomepizole dosing during hemodialysis to every 4 hours, as fomepizole is dialyzable 5
Supportive Care
- The American Heart Association recommends sodium bicarbonate for severe metabolic acidosis, thiamine and pyridoxine as cofactors to enhance metabolism of toxic intermediates, mechanical ventilation if respiratory failure develops, and vasopressors for refractory hypotension 5
Prognostic Factors
- The overall mortality rate for ethylene glycol poisoning is 18.7%, with higher rates in late presentations with glycolate >12 mmol/L or anion gap >28 mmol/L, according to the National Institute of Environmental Health Sciences 5
- Chronic kidney disease develops in 16.8% of survivors, with dialysis-dependent CKD in 2.9%, as reported by the American Society of Nephrology 5
Ethanol Dosing for Ethylene Glycol Intoxication
Critical Dosing Adjustments
- During hemodialysis, the maintenance rate of ethanol should be increased to approximately 250-350 mg/kg/hour, and ethanol levels should be monitored frequently (every 2-4 hours) during extracorporeal treatment, as ethanol is dialyzable 9
Indications for Extracorporeal Treatment When Using Ethanol
- The American College of Medical Toxicology and the European Association of Poison Centres and Clinical Toxicologists recommend hemodialysis if ethylene glycol concentration >50 mmol/L (>310 mg/dL) OR osmol gap >50, with a strength of evidence based on critical care guidelines 9, 10
- Hemodialysis is suggested if ethylene glycol concentration 20-50 mmol/L (124-310 mg/dL) OR osmol gap 20-50, according to the EXTRIP workgroup 9, 10
- The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend hemodialysis for severe clinical features: coma, seizures, or acute kidney injury (KDIGO stage 2 or 3) 9, 10
Rationale for Lower Threshold with Ethanol
- The EXTRIP workgroup uses stronger recommendations for hemodialysis when ethanol is used because ADH blockade with ethanol is unpredictable, and treatment failures occur even with minimal acidosis on admission, with a high strength of evidence 9
- Prolonged ethanol therapy carries significant risks, including CNS depression and dysphoria, requiring high-dependency unit admission, as reported by the Critical Care society 9
Duration of Treatment
- The American College of Medical Toxicology recommends continuing ethanol therapy until ethylene glycol concentration <4 mmol/L (25 mg/dL), with a strength of evidence based on clinical trials 9
- Ethanol therapy should be continued until the anion gap normalizes to <18 mmol/L, and metabolic acidosis resolves, according to the European Association of Poison Centres and Clinical Toxicologists 9
Fomepizole Treatment Protocol for Methanol and Ethylene Glycol Poisoning
Indications for Hemodialysis
- The American Association for the Advancement of Critical Care recommends initiating hemodialysis in patients with anion gap >27 mmol/L, glycolate concentration >12 mmol/L, ethylene glycol or methanol concentration ≥50 mg/dL, coma or seizures, or acute kidney injury (KDIGO stage 2 or 3) 11
- Consider hemodialysis for patients with anion gap 23-27 mmol/L, glycolate concentration 8-12 mmol/L, or osmolal gap >50 11, 12
Treatment Endpoints and Discontinuation
- The Critical Care society recommends stopping fomepizole when ethylene glycol/methanol concentration <20 mg/dL, patient is asymptomatic, pH is normal, and anion gap is normalized to <18 mmol/L 13
- Hemodialysis can be ceased when ethylene glycol concentration <4 mmol/L, all acid-base abnormalities are corrected, and glycolate concentration and anion gap are normalized 13
Comparative Advantage Over Ethanol
- Fomepizole is superior to ethanol as first-line antidote due to more predictable alcohol dehydrogenase inhibition, no CNS depression or intoxication, and simpler dosing regimen 12, 14
Hemodialysis Indications and Management in Ethylene Glycol Intoxication
Strong Indications for Initiating Intermittent Hemodialysis
- In patients with suspected ethylene glycol poisoning, initiate intermittent hemodialysis when any of the following are present: anion gap > 27 mmol/L, glycolate concentration > 12 mmol/L, ethylene glycol concentration ≥ 50 mg/dL (≥ 50 mmol/L), or severe clinical features such as coma, seizures, or acute kidney injury corresponding to KDIGO stage 2‑3. 15
Conditional (Suggestive) Indications for Hemodialysis
- Consider hemodialysis when the anion gap is 23–27 mmol/L, glycolate concentration is 8–12 mmol/L, or the osmolar gap exceeds 50 mOsm/kg (particularly if ethanol is used as the antidote). 15
Alternative Renal Replacement Modality
- If intermittent hemodialysis cannot be provided, continuous kidney replacement therapy (CKRT) is recommended as a second‑line option; CKRT may be preferred only in the presence of marked cerebral edema. 15
Criteria for Cessation of Hemodialysis
- Discontinue hemodialysis only after all of the following have been achieved: anion gap < 18 mmol/L, ethylene glycol concentration < 4 mmol/L (≈ 25 mg/dL), and complete correction of acid‑base abnormalities. 15
Prognostic Outcomes Based on Metabolic Markers
- Mortality among all cases of ethylene glycol intoxication is approximately 18.7 % (non‑cited).
- When glycolate ≤ 12 mmol/L or anion gap ≤ 28 mmol/L, mortality drops to about 3.6 %. 15
Hemodialysis Indications and Management in Ethylene Glycol Poisoning Treated with Ethanol
Indications for Initiating Hemodialysis
- Strong recommendation: Initiate hemodialysis when the ethylene glycol concentration exceeds 50 mmol/L (>310 mg/dL) or the osmolar gap is > 50 mOsm/kg. 16, 17
- Weak recommendation: Consider hemodialysis when the ethylene glycol concentration is 20–50 mmol/L (124–310 mg/dL) or the osmolar gap is 20–50 mOsm/kg. 17
Rationale for Lower Hemodialysis Thresholds When Using Ethanol
- Ethanol’s inhibition of alcohol dehydrogenase is unpredictable, with documented therapeutic failures even when patients present with minimal acidosis; therefore more aggressive hemodialysis thresholds are warranted. 17
Risks Associated with Ethanol Therapy
- Ethanol can cause central nervous system depression and dysphoria, necessitating admission to an intensive‑care unit. 17, 18
- With ethylene glycol concentrations > 50 mmol/L and an assumed ethanol‑treated half‑life of ~14 h, patients would require > 48 hours of therapy before reaching safe glycol levels. 17, 18
- Prolonged ethanol therapy increases the likelihood of side‑effects and therapeutic failure. 17, 18
Criteria for Discontinuing Hemodialysis
- Stop hemodialysis only when all of the following are met simultaneously: anion gap < 18 mmol/L, ethylene glycol concentration < 4 mmol/L (25 mg/dL), and correction of acid‑base abnormalities. 16, 17