How Should Patients Exposed to Ethylene Glycol Be Treated and Managed?
Course: WB 4342
CE Original Date: March 20, 2020
CE Expiration Date: March 20, 2022
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After completing this section, you will be able to describe treatment strategies for managing ethylene glycol poisoning cases.
Treatment should not be delayed pending results of ethylene glycol serum levels if the patient’s condition or history suggests such poisoning. Treatment advice can be obtained from a regional poison control center or medical specialists such as the following with expertise and experience treating patients exposed to ethylene glycol:
- Board-certified occupational and environmental medicine physicians
- Board-certified pediatric environmental health specialists
- Board-certified medical toxicologists
For initial patient stabilization, the clinician should first assess and secure the patient’s airway, breathing, and circulation.
Gastrointestinal decontamination measures, such as activated charcoal, gastric lavage, and gastric aspiration, provide little benefit in ethylene glycol poisoning because ethylene glycol is rapidly absorbed (Sivilotti 2018).
Specific treatment for ethylene glycol poisoning may include the following:
- Sodium bicarbonate to temporarily correct the metabolic acidosis, as indicated
- Fomepizole or ethanol to competitively inhibit metabolism of ethylene glycol to its more toxic metabolites (Baud et al. 1988; Brent et al. 1999; Jones AL and Volans 1999; Sivilotti 2018)
- If indicated, hemodialysis to remove ethylene glycol and glycolic acid (Bey et al. 2002; Cheng et al. 1987; Gabow et al. 1986; Jacobsen and McMartin 1997; Malmlund et al. 1991; Moreau et al. 1998; Sivilotti 2018; Stokes and Aueron 1980).
The above treatment strategies are effective in most cases, but if treatment is delayed, renal failure and death can occur (Leth and Gregersen 2005; Pellegrino et al. 2006).
Fomepizole, an alcohol dehydrogenase enzyme (ADH) antagonist, is the preferred therapy for ethylene glycol poisoning. The American Academy of Clinical Toxicology developed the following criteria for using fomepizole rather than ethanol (Barceloux et al. 1999):
- Ingestion of multiple substances, resulting in depressed level of consciousness
- Altered consciousness
- Lack of adequate intensive care staffing or laboratory support to monitor ethanol administration
- Relative contraindications to ethanol
- Critically ill patient with an anion-gap metabolic acidosis of unknown origin and potential exposure to ethylene glycol
- Patients with active hepatic disease
Fomepizole therapy might obviate the need for hemodialysis in the absence of renal insufficiency and significant metabolic acidosis (Battistella 2002; Borron et al. 1999; Brent 2001; Bronstein et al. 2009; Druteika et al. 2002; Harry et al. 1998; Harry et al. 1994; Watson 2000).
In comparison with ethanol (Lepik et al. 2009), fomepizole
- is easier to use clinically and requires less monitoring,
- has a slower rate of elimination,
- has a longer duration of action,
- has a reasonable dosing schedule,
- has less potential for adverse effects,
- is easier to administer,
- results in shorter hospital stays,
- has more predictable and prolonged results, and
- does not cause central nervous system (CNS) depression or hypoglycemia.
If fomepizole is unavailable or the patient has a known allergy, alcohol dehydrogenase can be blocked with 10 mL/kg of a 10% ethanol solution, followed by 1 mL/kg of 10% ethanol solution infused per hour. Titrate to a serum ethanol concentration of 100 mg/dL (Sivilotti 2018).
The disadvantages of ethanol are that it
- requires continuous administration and frequent monitoring of serum ethanol and glucose levels,
- can cause CNS depression and hypoglycemia, and
- poses problems in patient care, such as drunkenness.
Although ethanol costs much less, the savings might be offset by additional costs for
- monitoring the patient,
- laboratory tests, and
- hemodialysis for some patients.
Hemodialysis can rapidly remove toxic acid metabolites and parent alcohols. Several studies (Barceloux et al. 1999; Brent et al. 1999; Jammalamadaka and Raissi 2010; Sivilotti 2018) suggest considering hemodialysis when
- serum ethylene glycol levels exceed 50 mg/dL (8.1 mmol/L),
- severe acidemia (pH <7.25) or fluid/electrolyte disturbances persist despite ethanol or fomepizole therapy,
- vital signs continue to deteriorate despite intensive supportive treatment, or
- renal failure develops.
Continue hemodialysis until
- acidosis is controlled, and
- serum ethylene glycol level falls below 20 mg/dL.
When renal function is preserved, patients often can be treated without hemodialysis. This outcome underscores the effectiveness of supportive care and the use of fomepizole in the treatment of ethylene glycol poisoning, even at levels that have traditionally required hemodialysis (Buchanan et al. 2010; Levine et al. 2012; Velez L. I. et al. 2007).
Thiamine and pyridoxine are two water-soluble B-complex vitamins that act as metabolic cofactors in the metabolism of ethylene glycol. The benefits of giving supplemental thiamine (100 mg IV) or pyridoxine (50 mg IV) to patients poisoned with ethylene glycol are unknown. However, both are routinely administered, particularly if the patient’s nutritional status is suspect (Sivilotti 2018).
For those pediatric patients who do show signs of ethylene glycol poisoning, the diagnostic and treatment considerations described above for adults largely apply. The limited published experience with fomepizole supports its safe and effective use in children at the same dosing protocol given above
(Brent 2010; Caravati et al. 2004; Schwerk et al. 2007; Sivilotti 2018).
- Supportive care is the cornerstone of treatment of the poisoned patient.
- Because ethylene glycol is rapidly absorbed, gastrointestinal decontamination has little role in treatment.
- Fomepizole therapy might obviate the need for hemodialysis in the absence of renal insufficiency and significant metabolic acidosis.
- A regional poison control center or medical specialists with expertise and experience treating patients exposed to ethylene glycol can provide treatment advice.