Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM) 

Ethylene Glycol and Propylene Glycol Toxicity
How Should Patients Exposed to Ethylene Glycol Be Evaluated?

Learning Objectives

Upon completion of this section, you should be able to describe

• the primary focuses of the exposure history and
• how the actual clinical presentation changes over time as intoxication evolves.

Introduction

Ethylene glycol ingestion is a medical emergency requiring prompt recognition and aggressive treatment.

• The actual clinical presentation changes over time as intoxication evolves.
• Signs and symptoms depend on the amount ingested and concurrent use of alcohol.

Therefore, making a correct diagnosis requires a reliable history of the time, route, and magnitude of exposure. In some cases, however, a detailed history can be difficult to obtain because of the patient’s altered mental state. If ethylene glycol poisoning is strongly suspected, begin appropriate treatment while waiting for confirmation by laboratory results (Stokes and Aueron 1980; Johnson, Meggs et al. 1999).

Patients who have been exposed to ethylene glycol should undergo a thorough medical evaluation. Early and accurate diagnosis is important in deciding appropriate care strategies. In cases of ethylene glycol exposure, medical evaluation should include

• an exposure history,
• a physical examination,
• an assessment of clinical presentation, and
• laboratory tests.

This section focuses on the first three items, which are typically conducted during the patient’s visit to your office. Recommended tests are discussed in the next section.

Exposure History

Although environmental exposures to ethylene glycol are a concern, nearly all cases of ethylene glycol poisoning are due to ingestions (Agency for Toxic Substances and Disease Registry 1997).

• A careful history of possible substance abuse and a meticulous search in the home for ethylene glycol-containing compounds should be made in all suspected poisonings.
• A history of ethanol abuse may suggest ingestion of ethylene glycol as an ethanol substitute. Teens may experiment with this compound.
• Regional poison control centers can often assist in identifying the contents of bottles and packages if product labels do not list the chemical ingredients.
• Inquiring about similar symptoms in family members, friends, pets and coworkers may be helpful in identifying a common source of exposure.

Physical Examination

The patient’s vital signs should be monitored. Although not specific for ethylene glycol intoxication, the following symptoms have been associated with moderate or severe poisoning (Friedman, Greenberg et al. 1962; Parry and Wallach 1974):

• tachypnea,
• tachycardia,
• mild hypertension, and
• low-grade fever.

A complete neurologic examination should be performed. Pay special attention to

• mental status,
• gait, and
• balance.

Clinical Presentation

Patients who have ingested ethylene glycol often progress through three clinical stages (Friedman, Greenberg et al. 1962) (described earlier, Stages of Ethylene Glycol Intoxication) that represent a continuum. Individual patients may develop any combination of organ or systemic effects (Table 1). The time course for each stage, as well as the severity of illness, depends on the amount of ethylene glycol ingested and whether ethanol was ingested concurrently.

Stage 1

During the first 12 hours after ingestion, the following CNS effects predominate

• headache,
• slurred speech,
• confusion,
• tremor, and
• nystagmus.

Stage 2

Stage 2 begins 12-24 hours after ingestion and is caused by the products of ethylene glycol metabolism. The primary manifestations are cardiopulmonary

• tachypnea,
• tachycardia, and
• hypertension.

You may also see

• hypotension,
• dysrhythmias,
• respiratory distress syndrome,
• pulmonary edema, and
• profound metabolic acidosis.

Stage 3

Stage 3 occurs 24-72 hours after ingestion, if the condition is not treated. Acute renal dysfunction may occur, ranging from mild elevations in BUN and serum creatinine to oliguric renal failure.

• Renal dysfunction usually resolves, but may be irreversible.
• Myopathy and bone marrow suppression have also been reported.

In some cases, cranial nerve abnormalities may develop several days after exposure. These neurologic sequelae are usually found when treatment is delayed or inadequate.

Key Points

• A detailed history is important in diagnosing ethylene glycol poisoning.
• Prompt recognition and early therapeutic intervention are essential to preventing latent effects and potential sequelae of ethylene glycol poisoning.
• Patients poisoned with ethylene glycol may initially appear inebriated and may lack other signs and symptoms of severe toxic exposure.
• After a characteristic latent period, metabolites of ethylene glycol can cause potentially life-threatening illness.

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