Causes and Biological Mechanisms
Ethylene glycol poisoning is caused by ingesting products containing this toxic alcohol, such as antifreeze, hydraulic brake fluids, de-icing solutions, and some solvents. Ethylene glycol itself is relatively non-toxic, but once ingested, the liver metabolizes it using an enzyme called alcohol dehydrogenase. This process converts the substance into toxic byproducts, primarily glycolic acid and oxalic acid. These acids cause severe metabolic acidosis (dangerous acidity in the blood) and form calcium oxalate crystals that accumulate in the kidneys and other tissues, causing physical damage and organ failure.

Risk Factors
Several factors increase the likelihood of exposure:

• Young Children and Pets: The sweet taste and often colorful appearance of antifreeze make it attractive to children and animals.
• Improper Storage: Storing chemicals in unlabled containers, such as soda bottles or jars, significantly raises the risk of accidental ingestion.
• Substance Abuse: Individuals struggling with alcohol use disorder may consume ethylene glycol as a cheap or accessible substitute for ethanol, despite its lethality.
• Mental Health Struggles: It is sometimes used as a method of self-harm or suicide.

Prevention Strategies
Preventing poisoning relies on limiting access and choosing safer alternatives:

• Safe Storage: Keep all automotive and industrial chemicals in their original, clearly labeled containers, stored high up and locked away from children.
• Safer Formulations: When possible, purchase antifreeze made with propylene glycol, which is considerably less toxic than ethylene glycol.
• Clean Up Spills: Immediately clean up any radiator fluid leaks in garages or driveways to protect pets and wildlife.
• Safety Caps: Ensure all hazardous product bottles have functioning child-resistant safety caps.

Signs and Symptoms
Symptoms typically evolve in three distinct stages over time, though these stages can overlap depending on the amount ingested.

• Stage 1 (Neurological, 30 minutes to 12 hours): The person may appear "drunk" but without the smell of alcohol on their breath. Symptoms include slurred speech, confusion, dizziness, nausea, vomiting, and sleepiness. In severe cases, this can progress to seizures or coma.
• Stage 2 (Cardiopulmonary, 12 to 24 hours): As toxic acids build up, the body tries to compensate by breathing rapidly. Symptoms include rapid heart rate, high blood pressure, and deep, fast breathing (hyperventilation).
• Stage 3 (Renal, 24 to 72 hours): The final stage involves kidney damage. Symptoms include flank (side) pain, a noticeable decrease in urine output, and bloody urine.

Diagnostic Tests
Clinicians use a combination of history and lab tests to confirm diagnosis:

• Blood Tests: Doctors check for an elevated "anion gap" (a sign of high acid levels) and an "osmol gap" (a sign of unmeasured alcohols in the blood). Specific ethylene glycol levels can be measured, but results may take time.
• Urinalysis: Under a microscope, urine may show needle-shaped or envelope-shaped calcium oxalate crystals, which are a hallmark sign of this poisoning.
• Wood’s Lamp: Since some antifreeze contains fluorescent dye, doctors may shine a UV light on the patient's urine or mouth to look for a glowing color, though the absence of a glow does not rule out poisoning.

Differential Diagnosis
Doctors must distinguish this from other causes of metabolic acidosis and altered mental state, such as methanol poisoning (windshield wiper fluid), diabetic ketoacidosis, severe alcohol intoxication, or salicylate (aspirin) overdose.

Emergency Treatment
Treatment is a medical emergency and must take place in a hospital. The goal is to stop the body from converting ethylene glycol into toxic acids and to remove the toxin from the blood.

• Antidotes: The primary treatment is the administration of an antidote, such as fomepizole or ethanol (pharmaceutical-grade alcohol). These substances compete for the alcohol dehydrogenase enzyme, effectively blocking the liver from creating the toxic byproducts. Fomepizole is preferred because it is easier to dose and has fewer side effects.
• Hemodialysis: If the patient has high levels of ethylene glycol, severe kidney failure, or dangerous acidity levels that do not respond to medication, hemodialysis is used. This machine filters the blood to mechanically remove both the toxin and its acidic metabolites.
• Supportive Care: Intravenous fluids and sodium bicarbonate are often given to correct dehydration and neutralize the acid in the blood. If the patient is unable to breathe or protect their airway due to coma, intubation (a breathing tube) may be necessary.

When to Seek Medical Care
Call emergency services or poison control immediately if you suspect someone has swallowed antifreeze or engine coolant. Do not wait for symptoms to appear.

• Red-Flag Symptoms: Seek immediate help if a person appears intoxicated without drinking alcohol, has trouble breathing, becomes unresponsive, or has a seizure.
• Emergency Action: Bring the container of the ingested substance to the hospital if possible, as this helps doctors determine the toxicity level.

Severity
Ethylene glycol poisoning is a severe, life-threatening condition. The toxicity is dose-dependent, but even small amounts (as little as a mouthful in children or a few ounces in adults) can be lethal if untreated. The severity is largely determined by the time elapsed between ingestion and treatment; the longer the toxin remains in the body, the more toxic metabolites are produced.

Prognosis and Disease Course
With early diagnosis and prompt treatment (usually within a few hours of ingestion), the prognosis is excellent, and most patients recover fully with no long-term effects. However, if treatment is delayed until Stage 3 (renal failure) has begun, the risk of death or permanent disability increases significantly.

Complications
Delay in care can lead to serious complications:

• Acute Kidney Failure: This is the most common serious complication. While many patients recover kidney function after weeks or months, some may develop permanent kidney damage requiring lifelong dialysis or transplant.
• Neurological Damage: In rare cases, severe poisoning can lead to lasting brain damage, cranial nerve deficits (such as facial paralysis or vision issues), or movement disorders.
• Multi-Organ Failure: Severe acidosis can lead to shock and cardiac arrest.

Impact on Daily Life
For survivors who receive early treatment, there is typically no long-term impact on daily life, and they return to their previous level of health. However, those who suffer severe kidney injury may face a long road to recovery. This can involve weeks of hospitalization, temporary dialysis, and ongoing monitoring of kidney function. Patients with permanent renal failure will need to adjust their daily routine around dialysis schedules and dietary restrictions.

Mental and Emotional Health
If the poisoning was a result of a suicide attempt or substance abuse, recovery involves not just physical healing but also psychiatric support. Engaging with mental health professionals and addiction specialists is a critical part of the recovery process to prevent recurrence.

Questions to Ask Your Healthcare Provider

• How much kidney damage has occurred, and is it likely to be permanent?
• Will I need dialysis, and if so, for how long?
• Are there any long-term dietary restrictions I need to follow to support my kidneys?
• What specific symptoms should I watch for that might indicate my condition is worsening?
• Do I need a referral to a nephrologist (kidney specialist) or a neurologist?

Q: Is it safe to induce vomiting if I swallow antifreeze?
A: No. Do not induce vomiting unless specifically instructed by a poison control center or a healthcare provider. Inducing vomiting can cause other complications, such as inhaling the vomit into the lungs. Call emergency services immediately instead.

Q: Does ethylene glycol smell like strong alcohol?
A: No, ethylene glycol is odorless. This makes it particularly dangerous because there is no chemical smell to warn a person or child that the liquid is toxic.

Q: Can a very small amount really kill a pet or child?
A: Yes. Ethylene glycol is extremely potent. A few tablespoons can be fatal for a child, and even smaller amounts (like liquid licked off a driveway) can kill a cat or small dog.

Q: Why do doctors give alcohol to treat this poisoning?
A: Doctors may administer pharmaceutical-grade ethanol because the liver prefers to metabolize ethanol over ethylene glycol. This distracts the liver enzyme, allowing the ethylene glycol to pass through the body unchanged in the urine rather than being turned into toxic acids.

Q: Is antifreeze the only source of ethylene glycol?
A: While antifreeze is the most common source, ethylene glycol can also be found in windshield washer fluids, brake fluids, certain solvents, and air conditioning coolants.