Ethylene Glycol Poisoning
Overview
Ethylene glycol poisoning is a medical emergency. Despite being widely recognized as a toxic substance, ethylene glycol remains readily available and continues to be fatally ingested. The most common source of ethylene glycol is automotive engine antifreeze or coolant. 2 While ethylene glycol poisoning may result in serious medical consequences, including death, early initiation of treatment in asymptomatic patients is generally associated with an excellent prognosis. 3
topOccurrence
Ethylene glycol poisoning occurs either intentionally (attempted abuse or suicide), or unintentionally through misuse or accident (environmental or occupational exposures). Each year, the American Association of Poison Control Centers (AAPCC) publishes a report of the Toxic Exposure Surveillance System (TESS), a compilation of human exposures to potentially toxic substances reported by poison centers across the country. In 2005, more than 6,000 exposures to ethylene glycol were reported in the U.S., resulting in 41 fatalities. This document only includes reported cases, therefore the actual number of ethylene glycol exposures may be greater. Ethylene glycol is a common poisoning requiring antidotal treatment. 1
* For complete information on the use of antidotes for the treatment of poisonings, contact a regional poison control center.
Adapted from Lai et al., 2005 Annual Report of the American Association of Poison Control Centers’ National Poisoning and Exposure Database. Clinical Toxicology 2006.
topMechanism of Toxicity
While ethylene glycol itself has a relatively low degree of toxicity, its metabolites are responsible for extensive cellular damage to various tissues, especially the kidneys. This injury is caused by the metabolites, glycolic and oxalic acid and their respective salts (glycolate and oxalate), through crystal formation and possibly other mechanisms. 4, 5The metabolism of ethylene glycol, illustrated in the diagram below, is a four-step process taking place primarily in the liver.
topClinical Course
Classically, the clinical course of ethylene glycol poisoning has been described in three stages: an early neurological stage, followed by an intermediate cardiopulmonary stage and finally, a late renal stage; however, in many instances, there may be considerable overlap among the three stages. One may predominate while another may be absent, or they may occur at unpredictable time intervals after ingestion. 4, 5, 6 In addition, the presence of co-ingested substances such as ethanol or other drugs may lead to an atypical presentation or clinical course. 4, 5 Regardless of presentation, it is essential that antidotal treatment be initiated as quickly as possible to halt the progression of the poisoning. 6
