What is the appropriate treatment for ethylene glycol ingestion?

Treatment of Ethylene Glycol Ingestion

All patients with ethylene glycol poisoning require immediate antidote therapy with fomepizole (preferred) or ethanol to block alcohol dehydrogenase, combined with supportive care and correction of metabolic acidosis; hemodialysis should be added based on specific biochemical and clinical criteria. 1

Immediate Antidote Therapy

Fomepizole (First-Line Antidote)

• Fomepizole is the preferred antidote over ethanol due to predictable pharmacokinetics, lack of CNS depression, no hypoglycemia risk, and easier dosing without need for continuous monitoring 2, 3
• Initiate immediately upon suspected ethylene glycol ingestion without waiting for confirmatory levels 1
• Fomepizole monotherapy (without hemodialysis) is safe and effective when the anion gap is <28 mmol/L, regardless of ethylene glycol concentration 4
• Even massive ingestions (ethylene glycol levels up to 700 mg/dL) can be successfully treated with fomepizole alone if renal function is intact and metabolic acidosis is minimal 5

Ethanol (Alternative Antidote)

• Use only when fomepizole is unavailable 1
• Requires careful monitoring of serum ethanol concentrations to maintain therapeutic levels 2
• Treatment failures have been observed with ethanol monotherapy, likely due to transient subtherapeutic concentrations 4
• Can be administered orally (including whisky via nasogastric tube) when intravenous formulations are unavailable 6

Indications for Hemodialysis

The EXTRIP workgroup provides clear thresholds for adding extracorporeal treatment (ECTR) to antidote therapy 1:

Strong Recommendations (Must Dialyze)

• Glycolate concentration >12 mmol/L 1
• Anion gap >27 mmol/L (when ethylene glycol exposure is confirmed) 1
• Severe clinical features: coma, seizures, or acute kidney injury (KDIGO stage 2 or 3) 1
• If using ethanol as antidote: ethylene glycol concentration >50 mmol/L (>310 mg/dL) OR osmol gap >50 1
• If no antidote available: ethylene glycol concentration >10 mmol/L (>62 mg/dL) OR osmol gap >10 1

Conditional Recommendations (Consider Dialysis)

• Glycolate concentration 8-12 mmol/L 1
• Anion gap 23-27 mmol/L (when ethylene glycol exposure is confirmed) 1
• If using fomepizole: ethylene glycol concentration >50 mmol/L (>310 mg/dL) OR osmol gap >50 1
• Chronic kidney disease with eGFR <45 mL/min/1.73m² 1

Key Prognostic Finding

• Mortality is only 3.6% when glycolate ≤12 mmol/L or anion gap ≤28 mmol/L, and outcomes with ECTR are not better than without ECTR in this subgroup 1
• Overall mortality in ethylene glycol poisoning is 18.7%, emphasizing the importance of early recognition and treatment 1

Hemodialysis Modality and Duration

Preferred Modality

• Intermittent hemodialysis is recommended over all other extracorporeal treatments when available 1
• If intermittent hemodialysis unavailable, use continuous kidney replacement therapy (CKRT) 1
• Ethylene glycol and glycolate are highly dialyzable with clearances exceeding 200 mL/min during high-efficiency hemodialysis 1

Cessation Criteria

• Stop hemodialysis when anion gap <18 mmol/L 1
• Alternatively, stop when ethylene glycol concentration <4 mmol/L (25 mg/dL) 1
• May also stop when acid-base abnormalities are corrected 1

Critical Dosing Adjustment

• Antidote dosing (fomepizole or ethanol) must be adjusted during hemodialysis due to removal of these agents by dialysis 1
• Failure to increase dosing during dialysis can result in subtherapeutic levels and treatment failure 1

Supportive Care

• Correct metabolic acidosis with sodium bicarbonate 1, 2
• Monitor for hypocalcemia (calcium oxalate crystal formation) 1
• Assess renal function serially as acute kidney injury develops in many cases 1
• Look for urinary oxalate crystals on urinalysis 3

Common Pitfalls to Avoid

• Do not wait for ethylene glycol levels to initiate antidote therapy - treat based on clinical suspicion 1
• Do not rely solely on reported dose to guide hemodialysis decisions 1
• Do not use ethanol monotherapy for high ethylene glycol concentrations (>50 mmol/L) without hemodialysis, as treatment failures occur 1, 4
• Do not forget to adjust fomepizole/ethanol dosing during hemodialysis 1
• Consider ethylene glycol poisoning in any patient with unexplained anion gap metabolic acidosis, especially with normal lactate and normal renal function initially 3