Do all patients with significantly elevated ethylene glycol levels need to be dialyzed?

April 13, 2012, 6:21 pm

★★★½☆

Ethylene glycol elimination Kinetics and Outcomes in Patients Managed Without Hemodialysis. Levine M et al. Ann Emerg Med 2012 Jan 5 [Epub ahead of print]

Abstract

The keystones of treating ethylene glycol poisoning — aside from providing good supportive care — involve blocking the enzyme alcohol dehydrogenase  (with ethanol or fomepizole) and instituting hemodialysis. Dialysis enhances elimination of both ethylene glycol and its metabolites, and also corrects acid-base abnormalities.

In the past, many texts and experts recommended dialysis in some cases based solely on the ethylene glycol level. (The figure of 50 mg/dL was often measured.) However, since fomepizole became available, the indications for hemodialysis have generally become more limited, with many toxicologists suggesting that select patients can be treated with fomepizole alone.

This retrospective study supports that suggestions. The authors analyzed the records of 40 ethylene glycol (EG) poisoned patients (> 15 years old)  from 3 institutions with peak EG levels over 20 mg/dL who were treated with fomepizole but did not undergo hemodialysis. Patients characteristics included an average initial pH of 7.37 (range, 7.29 – 7.43), average peak EG level 127 mg/dL (range, 40 – 635 mg/dL) and average initial anion gap 15 mEq/L (range, 4 – 29 mEq/L).  All patients did well. The patient with the highest initial anion gap (29 mEq/L) had a pH of 7.30 and developed transient nonoliguric renal insufficiency (serum creatinine level increasing form 1.1 to 2.1 mg/dL). The calculated average ethylene glycol half-life after starting fomepizole was 14.6 h (range, 5.5 – 23.3 h).

The authors conclude that:

In selected patients with acute ethylene glycol toxicity (e.g., those with normal renal function and without severe metabolic acidosis), the use of fomepizole without adjunctive hemodialysis appears to be safe.

I think is is undoubtedly true, as illustrated by the cases the authors analyzed. But note the caveat: patients with significant metabolic acidosis (indicating the presence of toxic metabolites) and those with initial renal insufficiency will still likely need dialysis.Unfortunately, this important point is not made strongly enough in the article’s abstract.

 

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