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Potentially life-threatening emergency
Carbon monoxide poisoning
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Potentially life-threatening emergency

Carbon monoxide poisoning

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Contributors: Sanuja Bose BS, BA, Benjamin L. Mazer MD, MBA, Abhijeet Waghray MD
Other Resources UpToDate PubMed

Synopsis

Carbon monoxide (CO) is a colorless, tasteless, odorless gas that commonly causes both accidental and intentional poisoning. It is produced from the combustion of carbon-containing materials, most frequently from fires, faulty furnaces, and car exhausts. CO binds to hemoglobin in blood with a 250-fold greater affinity than oxygen, displacing oxygen to form carboxyhemoglobin (COHb), which causes tissue hypoxia. While smokers have a higher level of CO in their blood at baseline, at least 2% COHb in nonsmokers and at least 10% COHb in smokers can become symptomatic.

Mild exposure to CO can cause headaches, myalgias, dizziness, nausea, or neuropsychological impairment. More extreme exposures can cause confusion, loss of consciousness, coma, or death. Although cherry-red skin and mucous membranes have been considered characteristic of CO poisoning, they are not always visible. If an individual is chronically exposed to CO, they may experience more generalized fatigue, vertigo, and paresthesias or have abdominal disturbances such as pain or diarrhea.

Because CO binds to both myoglobin and cytochrome c oxidase, CO poisoning may more specifically cause cardiac damage and increases the risk of myocardial infarction and arrhythmia, most commonly QT prolongation. Patients with underlying coronary artery disease are at even greater risk of these effects.

Those subjected to CO poisoning acutely or chronically may experience permanent, long-term neurocognitive deficits, including impairments of memory and cognition, as well as impairments of motor and vestibular function. Neuropsychological effects may also occur, including depression and anxiety. Although improvement may be seen by 6 months or 1 year, these sequelae are mostly irreversible.

Higher short-term mortality is seen in patients with low pH (less than 7.2), with loss of consciousness, who require intubation, or who are exposed to fire.

Treatment primarily involves supportive care, particularly 100% oxygen administration, and removal from the contaminated environment. After removal of CO from the environment, CO will dissociate from hemoglobin within hours.

Pediatric Patient Considerations:
Infants and younger children may experience the effects of CO poisoning before older children and adults in the household, and the effects may be nonspecific (irritability, poor feeding).

Codes

ICD10CM:
T58.94XA – Toxic effect of carbon monoxide from unspecified source, undetermined, initial encounter

SNOMEDCT:
17383000 – Toxic effect of carbon monoxide

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Last Reviewed: 06/19/2019
Last Updated: 06/21/2019
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Potentially life-threatening emergency
Carbon monoxide poisoning
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Carbon monoxide poisoning (Mild to Moderate Poisoning) : Abdominal pain, Dizziness, Headache, Nausea, Malaise, Dyspnea, Myalgia, Blurry vision, Confusion
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