Symptoms ofcarbon monoxide poisoning

The symptoms of carbon monoxide poisoningaren't always obvious, particularly during low-level exposure.

A tension-type headache is the most common symptom ofmild carbon monoxide poisoning.Other symptoms include:

  • dizziness
  • nausea (feeling sick)and vomiting
  • tiredness and confusion
  • stomach pain
  • shortness of breath and difficulty breathing

The symptoms ofexposure to low levels of carbon monoxidecan be similar tothose of food poisoning and flu .But unlike flu,carbon monoxide poisoning doesn't cause a high temperature (fever).

The symptoms can gradually get worse with prolonged exposure to carbon monoxide, leading to a delay in diagnosis.

Your symptoms may be less severe when you're away from the source of the carbon monoxide. If this is the case you should investigate the possibility of a carbon monoxide leak, and ask a suitably qualified professional to check any appliances you think may be faulty and leaking gas.

The longer you inhalethe gas, the worse your symptoms will be. You may lose balance, vision and memory and, eventually, you may lose consciousness. This can happen within two hours if there's a lot ofcarbon monoxidein the air.

Long-term exposure to low levels of carbon monoxide can also lead to neurological symptoms, such as difficulty thinking or concentrating and frequent emotional changesfor example, becoming easily irritated, depressed or making impulsive or irrational decisions.

Breathing in high levels ofcarbon monoxidegas can cause more severe symptoms. These may include:

  • impaired mental state andpersonality changes (intoxication)
  • vertigo the feeling that you or the environment around you is spinning
  • ataxia loss of physical co-ordination caused byunderlying damage to the brain and nervous system
  • breathlessness and tachycardia (a heart rateof more than 100 beats per minute)
  • chest pain caused by angina or a heart attack
  • seizures an uncontrollable burst of electrical activity in the brain that causes muscle spasms
  • loss of consciousness in cases where thereare very high levels ofcarbon monoxide, death may occur withinminutes
Content supplied by the NHS Website

Medically Reviewed by a doctor on 21 Dec 2018