Ethylene glycol poisoning (antifreeze poisoning): symptoms and emergency care in the UK

UK Health Security Agency (UKHSA) describes ethylene glycol as a clear, colourless liquid with a syrup-like consistency. Because it is both a solvent and has a low freezing point, it is widely used in antifreeze solutions, de-icers and as an engine coolant. It is also used in paints, lacquers, dyes and inks, and in making polyester fibres and plastics.

For most people, contact comes from household and motoring products. UKHSA says antifreeze solutions for cars may have an ethylene glycol content of 60 to 100%, and that windscreen wash may contain up to 30%. It notes that there have been many reported cases of children consuming antifreeze, often mistaking it for a soft drink, and that exposure is likely to be minimal if products are used appropriately.

UKHSA recommends that products such as antifreeze and screen wash are stored in appropriate containers and kept out of the reach of children. Its toxicological overview also notes that intoxication has been reported after drinking contaminated water systems and illicit alcoholic drinks.

Small spills on the skin are unlikely to cause harm if washed off immediately, according to UKHSA, and splashes in the eyes may sting but should not lead to permanent damage. Breathing it in is not considered a serious risk. The danger is in swallowing it.

The UKHSA toxicological overview describes three main phases after swallowing. In the first, from about 30 minutes to 12 hours, there is central nervous system depression much like alcohol intoxication, with dizziness, agitation, nausea, vomiting, a fast heartbeat and raised blood pressure. In the second, at around 12 hours, effects on the heart and lungs develop, including fast breathing, breathlessness, blue lips or skin and a metabolic acidosis, which means the blood becomes too acidic. In the third, 24 to 36 hours after swallowing, the kidneys are affected, with flank pain, little or no urine and kidney injury. Some investigators report a fourth stage of delayed nerve damage.

UKHSA explains that much of the toxicity comes from the acids that the body produces when it breaks ethylene glycol down, including the formation of oxalic acid, which can form crystals in the kidney. Severe poisoning, if survived, can leave neurological effects such as facial paralysis, slurred speech, loss of motor skills and impaired vision.

Early symptoms can be subtle, which is why a history of possible swallowing matters more than how the person looks. The NHS notes that symptoms of poisoning can take a few hours or days to start, and that it is important to get medical advice quickly if there is a chance someone could be poisoned.

• Appearing drunk, drowsy or unsteady without having had alcohol.

• Nausea or vomiting.

• Fast breathing or breathlessness.

• Fast heartbeat.

• Back or flank pain and passing very little urine, later on.

• Confusion, seizures or loss of consciousness in severe cases.

The NHS says to call 999 or go to A&E if you think you, a child or someone else may have swallowed, touched or breathed in something harmful, or if someone has lost consciousness, stopped breathing, has severe difficulty breathing or has a seizure. It says to call NHS 111 if you are not sure whether something swallowed is harmful, and not to drive to A&E but to ask someone to drive you or call 999.

While waiting for help, the NHS advises looking for what caused the poisoning, taking the substance or its packaging to show the doctors if possible, putting an unconscious person who is breathing in the recovery position and starting CPR if they are unresponsive and not breathing. It says not to try to make someone sick and not to give them anything to eat or drink.

For skin contact, UKHSA says to remove soiled clothing and wash the area with lukewarm water and soap for at least 10 to 15 minutes and seek medical advice. For the eyes, remove contact lenses and rinse with lukewarm water for at least 10 to 15 minutes and seek medical advice.

The NHS says poisoning needs hospital treatment because it can be life threatening. Treatment depends on the substance and may include antidotes, treatments to help the symptoms such as fluids into a vein, and removing the substance from the body.

UKHSA explains the principle for ethylene glycol: the enzyme alcohol dehydrogenase has a much greater affinity for ethanol than for ethylene glycol, so alcohol given under medical supervision has been used to reduce the production of the harmful breakdown products, and a selective enzyme inhibitor such as fomepizole may be used to block the metabolism. Doctors monitor blood chemistry, breathing and kidney function, and kidney support may be needed if the kidneys are damaged. The exact approach is decided by the treating team, who may take specialist poisons advice.

Prevention is mainly about storage. The NHS suggests storing medicines and chemicals out of reach of children, ideally in a locked cupboard, and keeping liquid cleaning products and chemicals in their original containers so that they are not mistaken for drinks. The same applies to antifreeze, screen wash and de-icer, which should never be decanted into drinks bottles.

Outcomes depend on how much was swallowed and how soon treatment began. UKHSA says severe poisoning can be fatal and can cause lasting nerve effects, while small spills on the skin are unlikely to cause harm.

Poisoning is an emergency and is managed by NHS ambulance and emergency department services, with intensive care where needed. Private care does not usually change this pathway, because emergency treatment happens at the nearest suitable hospital.