Carbon Monoxide Poisoning - Symptoms

Symptoms

Symptoms of carbon monoxide poisoning range from mild flu-like symptoms (such as a headache or stomachache without fever) to severe signs of heart and brain damage. Prolonged exposure to low levels of carbon monoxide over many days may result in death.

People respond differently to the same level of carbon monoxide. Because of this, carbon monoxide poisoning can range from mild to severe in different people with the same level of exposure.

A person who has mild symptoms usually does not even suspect carbon monoxide poisoning. Early symptoms can mimic the flu or a number of other conditions with similar symptoms, which can make it difficult for a doctor to diagnose.² It is possible that a person with more severe poisoning may not even be aware of the seriousness of the condition because the exposure to carbon monoxide may cause fatigue and confusion. If a person has symptoms of carbon monoxide poisoning or if carbon monoxide poisoning is suspected, first get the person out of the polluted area, and then call 911 .

Symptoms of carbon monoxide poisoning are often similar to symptoms of other illnesses. These symptoms include:³

• Headache.
• Nausea, vomiting (often seen in children).
• Dizziness.
• Fatigue.

More severe symptoms may include:

• Confusion, drowsiness.
• Rapid breathing or pulse rate.
• Vision problems.
• Chest pain.
• Convulsions, seizures.
• Loss of consciousness.

Symptoms of carbon monoxide poisoning change with different blood concentrations of carboxyhemoglobin (hemoglobin that has bonded with carbon monoxide instead of oxygen).

Some situations may provide clues to carbon monoxide exposure. For example, if a family or group of people who live or work in the same building complain of headaches or flu-like symptoms, these symptoms may be caused by high levels of carbon monoxide. Also, family pets living in the home may become sick, which can be another clue to diagnosing carbon monoxide poisoning.² In the winter, unexplained headaches, nausea, or dizziness may be caused by heating systems that are not working correctly and are causing a buildup of carbon monoxide.

Delayed symptoms or long-term adverse effects of carbon monoxide poisoning can occur days or weeks after poisoning. The delayed symptoms or effects may include memory loss, changes in personality, disorientation, impaired reasoning ability, and behavioral or learning difficulties.⁴