Ethylene Glycol Toxicity: The Role of Serum Glycolic Acid In Hemodialysis

Abstract

Objective: To correlate serum glycolic acid levels with clinical severity and outcome in ethylene glycol poisoning and to determine if glycolic acid levels are predictive of renal failure and the need for hemodialysis. Methods: We measured serum ethylene glycol and glycolic acid levels by gas chromatography/mass spectrometry for 41 admissions (39 patients) for ethylene glycol ingestion and performed retrospective chart reviews. Results: Eight patients died, all of whom developed acute renal failure. Of the survivors, 15 also developed acute renal failure, whereas 18 did not. Of those with normal renal function, 8 had glycolic acid levels below detection limits (1.0 mmol/L: pH 7.29 (7.12–7.46); bicarbonate, 14.7 mmol/L (4–23); anion gap, 16.5 mmol/L (10–26); glycolic acid, 6.8 mmol/L (2.6–17.0); ethylene glycol, 269.1 mg/dL (6–675). No acute renal failure with glycolic acid 1.0 mmol/L, ≥6.2 h; no acute renal failure with glycolic acid 2 = 0.7724), pH (r² = 0.7921), and bicarbonate (r² = 0.6579); poor correlations (r² 20 mmol/L is 95.6% sensitive and 94.4% specific for acute renal failure when ethylene glycol is present. Likewise, initial pH <7.30 is 100% sensitive and 88.5% specific for acute renal failure. Conclusion: We propose glycolic acid <8 mmol/L as a criterion for the initiation of hemodialysis in ethylene glycol ingestion. Patients with glycolic acid 20 mmol/L or pH <7.30 predicts acute renal failure.