⚠️ MEDICAL EMERGENCY
If you suspect ethylene glycol poisoning, call 911 or your local emergency number immediately.
Contact Poison Control: 1-800-222-1222 (US)
Overview
Ethylene glycol poisoning is a medical emergency that occurs when someone ingests ethylene glycol, a toxic alcohol commonly found in antifreeze, de-icing solutions, and some industrial products. Despite its sweet taste, ethylene glycol is extremely poisonous and can cause severe metabolic disturbances, organ failure, and death if not treated promptly.
The toxicity of ethylene glycol comes not from the parent compound itself, but from its metabolites. When ethylene glycol is metabolized in the liver, it produces highly toxic compounds including glycolic acid and oxalic acid. These metabolites cause severe metabolic acidosis, calcium oxalate crystal formation, and progressive damage to the central nervous system, cardiovascular system, and kidneys.
Ethylene glycol poisoning can occur accidentally, particularly in children attracted to its sweet taste, or intentionally in suicide attempts. Industrial workers may also be exposed through inhalation or skin contact, though ingestion is the primary route of toxicity. The lethal dose for adults is approximately 100 mL (about 3.4 ounces), though serious toxicity can occur with smaller amounts. Early recognition and treatment are crucial, as the window for preventing severe complications is limited.
Symptoms
Ethylene glycol poisoning progresses through three distinct stages, each with characteristic symptoms. The timing and severity of symptoms depend on the amount ingested and whether treatment is initiated.
Stage 1: Neurological (30 minutes to 12 hours)
Similar to alcohol intoxication but without the typical alcohol odor on breath:
- Euphoria and confusion
- Slurred speech
- Dizziness and lack of coordination
- Nausea and vomiting
- Depression or altered mood
- Depressive or psychotic symptoms
- Seizures in severe cases
- Coma
Stage 2: Cardiopulmonary (12 to 24 hours)
As toxic metabolites accumulate, cardiovascular and respiratory symptoms develop:
- Rapid heart rate (tachycardia)
- High blood pressure initially, then low blood pressure
- Rapid breathing (hyperventilation)
- Pulmonary edema (fluid in lungs)
- Heart failure
- Fainting or loss of consciousness
- Multi-organ failure
Stage 3: Renal (24 to 72 hours)
Kidney damage becomes apparent as calcium oxalate crystals form:
- Flank pain
- Decreased or absent urine output
- Blood in urine
- Acute kidney failure
- Severe metabolic acidosis
Early Warning Signs
- Apparent intoxication without alcohol smell
- Sweet taste reported after ingestion
- Nausea and vomiting
- Abdominal pain
- Headache
- Dizziness
Associated Behaviors
- Abusing alcohol (risk factor)
- History of suicide attempts
- Access to automotive products
- Occupational exposure
Critical Signs Requiring Immediate Action
- Known or suspected antifreeze ingestion
- Unexplained metabolic acidosis
- Altered mental status with no alcohol odor
- Calcium oxalate crystals in urine
- Unexplained kidney failure
- Visual disturbances or blindness
Causes
Ethylene glycol poisoning occurs through various routes of exposure, with ingestion being the most common and dangerous.
Sources of Ethylene Glycol
- Automotive products:
- Antifreeze (most common source)
- Engine coolants
- Hydraulic brake fluids
- De-icing solutions
- Industrial products:
- Solvents
- Paints and lacquers
- Cosmetics
- Detergents
- Household items:
- Some cleaning products
- Photographic developing solutions
- Snow globes (small amounts)
Mechanisms of Poisoning
- Accidental ingestion:
- Children attracted to sweet taste and bright colors
- Mistaken for alcoholic beverages
- Improper storage in drink containers
- Pets drinking from puddles of antifreeze
- Intentional ingestion:
- Suicide attempts
- Substitute for ethanol in alcoholism
- Homicide (rare)
- Occupational exposure:
- Inhalation of vapors
- Skin absorption (minimal risk)
- Accidental ingestion
Toxic Metabolism
The toxicity pathway of ethylene glycol:
- Step 1: Ethylene glycol → Glycolaldehyde (via alcohol dehydrogenase)
- Step 2: Glycolaldehyde → Glycolic acid (causes metabolic acidosis)
- Step 3: Glycolic acid → Glyoxylic acid
- Step 4: Glyoxylic acid → Oxalic acid (forms calcium oxalate crystals)
Risk Factors
Several factors increase the risk of ethylene glycol poisoning:
Demographic Risk Factors
- Children: Attracted to sweet taste and bright colors
- Elderly: May mistake products due to cognitive impairment
- People with alcoholism: May use as ethanol substitute
- Individuals with depression or suicidal ideation
- Industrial workers: Mechanics, HVAC technicians
Environmental Risk Factors
- Improper storage of antifreeze products
- Transfer to unmarked or food containers
- Lack of bittering agents in antifreeze
- Easy accessibility of products
- Poor workplace safety measures
Behavioral Risk Factors
- History of substance abuse
- Previous suicide attempts
- Impulsive behavior
- Lack of awareness about toxicity
- Language barriers on product labels
Diagnosis
Early diagnosis of ethylene glycol poisoning is crucial for successful treatment. Diagnosis relies on clinical suspicion, laboratory findings, and sometimes direct measurement of ethylene glycol levels.
Clinical Assessment
- History:
- Witnessed or reported ingestion
- Access to antifreeze or similar products
- Timeline of symptom onset
- Absence of alcohol odor despite intoxication
- Physical examination:
- Vital signs (tachycardia, tachypnea, hypertension)
- Neurological status
- Signs of metabolic acidosis
- Kidney tenderness
Laboratory Tests
- Direct measurement:
- Serum ethylene glycol level (if available)
- Levels >20 mg/dL are toxic
- May not be readily available in all hospitals
- Indirect indicators:
- Severe metabolic acidosis with high anion gap
- Osmolar gap >10 mOsm/kg
- Calcium oxalate crystals in urine
- Hypocalcemia (low calcium)
- Elevated creatinine (kidney damage)
- Additional tests:
- Arterial blood gas
- Complete metabolic panel
- Urinalysis
- Lactate level
- Blood alcohol level
Imaging Studies
- Chest X-ray for pulmonary edema
- CT scan of brain if altered mental status
- Renal ultrasound for kidney evaluation
Wood's Lamp Test
Some antifreeze products contain fluorescein dye that fluoresces under ultraviolet light. Urine or vomitus may glow under Wood's lamp examination, though absence of fluorescence doesn't rule out poisoning.
Treatment
Treatment of ethylene glycol poisoning is time-critical and focuses on preventing the formation of toxic metabolites, correcting metabolic disturbances, and removing the poison from the body.
Immediate Management
- Stabilization:
- Airway, breathing, circulation assessment
- IV access and fluid resuscitation
- Cardiac monitoring
- Seizure management if needed
- Decontamination:
- Gastric lavage if within 1 hour (controversial)
- Activated charcoal is NOT effective
- Do not induce vomiting
Antidotal Therapy
- Fomepizole (preferred):
- Competitive inhibitor of alcohol dehydrogenase
- Prevents formation of toxic metabolites
- Loading dose: 15 mg/kg IV
- Maintenance: 10 mg/kg every 12 hours
- Continue until ethylene glycol <20 mg/dL
- Ethanol (alternative if fomepizole unavailable):
- Competes for alcohol dehydrogenase
- Target blood alcohol 100-150 mg/dL
- Requires close monitoring
- More side effects than fomepizole
Hemodialysis
Indications for immediate hemodialysis:
- Severe metabolic acidosis (pH <7.25)
- Kidney failure or anuria
- Ethylene glycol level >50 mg/dL
- Visual disturbances
- Deteriorating vital signs despite treatment
- Electrolyte abnormalities resistant to treatment
Supportive Care
- Metabolic acidosis correction:
- Sodium bicarbonate for severe acidosis
- Target pH >7.35
- Monitor electrolytes closely
- Cofactor supplementation:
- Thiamine 100 mg IV daily
- Pyridoxine 50 mg IV daily
- Helps convert glyoxylate to non-toxic metabolites
- Calcium replacement:
- For hypocalcemia from oxalate binding
- Monitor for tetany or seizures
- Additional measures:
- Folinic acid for metabolic support
- Magnesium replacement
- Treatment of complications
Prevention
Preventing ethylene glycol poisoning requires a combination of safe storage practices, public awareness, and regulatory measures.
Storage and Handling
- Safe storage practices:
- Keep in original, labeled containers
- Store in locked cabinets away from children
- Never transfer to food or drink containers
- Dispose of properly at hazardous waste facilities
- Workplace safety:
- Use proper ventilation
- Wear protective equipment
- Follow MSDS guidelines
- Provide safety training
Product Safety Measures
- Bittering agents:
- Addition of denatonium benzoate
- Makes antifreeze taste bitter
- Required in many states
- Doesn't prevent all ingestions
- Alternative products:
- Propylene glycol-based antifreeze (less toxic)
- Clearly labeled "pet-safe" options
- Consider toxicity when purchasing
Education and Awareness
- Educate families about antifreeze dangers
- Teach children not to taste unknown liquids
- Awareness campaigns for high-risk groups
- Clear warning labels in multiple languages
- Community poison prevention programs
Environmental Precautions
- Clean up antifreeze spills immediately
- Check vehicles for coolant leaks
- Properly maintain cooling systems
- Be aware of pets and wildlife exposure risks
- Report improper disposal
Complications
Delayed or inadequate treatment of ethylene glycol poisoning can lead to severe, potentially permanent complications:
Acute Complications
- Metabolic:
- Severe metabolic acidosis
- Electrolyte imbalances
- Hypocalcemia with tetany
- Hyperkalemia
- Neurological:
- Cerebral edema
- Seizures
- Coma
- Cranial nerve palsies
- Cardiovascular:
- Myocarditis
- Heart failure
- Arrhythmias
- Shock
Long-term Complications
- Kidney damage:
- Chronic kidney disease
- Need for long-term dialysis
- Kidney transplantation
- Neurological sequelae:
- Permanent brain damage
- Cognitive impairment
- Peripheral neuropathy
- Vision problems
- Psychological effects:
- Post-traumatic stress
- Depression
- Anxiety about recurrence
When to Seek Help
Call 911 Immediately If:
- Known or suspected antifreeze ingestion
- Found near open antifreeze containers
- Unexplained intoxication without alcohol odor
- Rapid onset of confusion and vomiting
- Difficulty breathing or chest pain
- Loss of consciousness
- Seizures
Information for Emergency Responders
When calling for help, provide:
- Product name and amount ingested (if known)
- Time of ingestion
- Patient's age and weight
- Current symptoms
- Any first aid given
- Medical history and medications
Poison Control Center
Contact Poison Control for immediate guidance:
- US: 1-800-222-1222
- Available 24/7
- Free and confidential
- Staffed by toxicology experts
Frequently Asked Questions
How quickly do symptoms appear after ingesting ethylene glycol?
Initial symptoms typically appear within 30 minutes to 12 hours after ingestion, resembling alcohol intoxication. However, the most serious effects may not manifest until 12-72 hours later as the body metabolizes ethylene glycol into toxic compounds. This delayed toxicity is why immediate medical treatment is crucial even if the person initially appears only mildly affected.
Can you survive ethylene glycol poisoning?
Yes, with prompt and appropriate treatment, survival rates are excellent. The key is early intervention before significant metabolism of ethylene glycol occurs. Treatment with fomepizole or ethanol can prevent the formation of toxic metabolites, and hemodialysis can remove both the parent compound and its metabolites. However, delayed treatment can result in permanent kidney damage, neurological problems, or death.
How is ethylene glycol poisoning different from methanol poisoning?
While both are toxic alcohols, they differ in their target organs and toxic metabolites. Ethylene glycol primarily causes kidney damage through calcium oxalate crystal formation, while methanol causes blindness through formic acid toxicity to the optic nerve. Both cause severe metabolic acidosis and are treated similarly with fomepizole or ethanol and hemodialysis, but the specific complications and long-term effects differ.
Why does antifreeze taste sweet?
Ethylene glycol itself has a sweet taste, which makes it particularly dangerous as children and animals may be attracted to it. This is why many jurisdictions now require the addition of bittering agents (denatonium benzoate) to antifreeze products. However, not all products contain these additives, and even with them, accidental ingestions can still occur, especially if someone drinks a large amount quickly.
Can pets be poisoned by ethylene glycol?
Yes, pets are extremely susceptible to ethylene glycol poisoning. Dogs and cats are often attracted to the sweet taste and may drink from puddles of leaked antifreeze. Even small amounts can be fatal - as little as 1 tablespoon can kill a cat, and 3 tablespoons can kill a medium-sized dog. Pet owners should use pet-safe antifreeze alternatives and clean up any spills immediately.
Is there a home test for ethylene glycol poisoning?
No, there is no reliable home test for ethylene glycol poisoning. While some antifreeze contains fluorescent dye that may cause urine to glow under black light, this is not a reliable diagnostic method. Any suspected ingestion requires immediate medical evaluation. Hospital laboratories can measure ethylene glycol levels directly or use indirect markers like osmolar gap and anion gap to assess poisoning severity.
References
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