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Carbon monoxide poisoning

Last reviewed: 6 Nov 2023
Last updated: 21 Nov 2023



History and exam

Key diagnostic factors

  • exposure to incomplete combustion of carbon-containing material
  • exposure to fire with smoke inhalation
  • nausea
  • headache
  • vomiting
  • blurred vision
  • dizziness
  • vertigo
  • altered consciousness
  • dyspnea
  • tachycardia
  • hypotension or hypertension
  • cardiac arrhythmias
  • pain
  • weakness
  • sleep changes
  • irritability
  • flu-like symptoms
More key diagnostic factors

Other diagnostic factors

  • exposure to methylene chloride
  • delayed neuropsychiatric features
  • other severe neurologic symptoms
  • cutaneous blistering
  • pulmonary edema
  • cardiac arrest
  • focal neurologic abnormalities (e.g., hemiplegia, truncal ataxia)
  • disseminated intravascular coagulation
Other diagnostic factors

Risk factors

  • exposure to incomplete combustion of carbon-containing material
  • exposure to fire with smoke inhalation
  • exposure to methylene chloride
More risk factors

Diagnostic investigations

1st investigations to order

  • carboxyhemoglobin level
  • ECG
  • cardiac monitoring
  • blood glucose
  • complete blood count
  • urea and electrolytes
  • creatinine
  • lactate
  • pH level
  • cardiac biomarkers
  • creatine kinase
More 1st investigations to order

Investigations to consider

  • chest x-ray
  • Mini Mental State Examination
  • CT head
  • magnetic resonance imaging and spectroscopy
  • liver function tests
  • pregnancy test
More investigations to consider

Treatment algorithm


all patients



Richard Moon, MD

Professor of Anesthesiology

Professor of Medicine

Division of Pulmonary, Allergy and Critical Care Medicine

Duke University




RM has been reimbursed by Merck for contributions to the Merck Manual.


Dr. Richard Moon would like to gratefully acknowledge Dr Jason Rose and Dr Prasanthi Govindarajan, previous contributors to this topic. PG declares that she has no competing interests. JR is a co-inventor on patent applications for the use of heme-based molecules as antidotes for CO poisoning. JR is a shareholder, officer, and director of Globin Solutions, Inc. Globin Solutions, Inc. has an exclusive license to this technology. Globin Solutions, Inc. had an option agreement to technology directed at using hydroxycobalamin for CO poisoning from Virginia Commonwealth University in the last 12 months. JR is an author of publications cited within this topic.

Peer reviewers

Richard S. Weisman, PharmD


Florida Poison Center




RSW declares that he has no competing interests.

Sean Patrick Nordt, MD, PharmD

Resident Physician

Department of Emergency Medicine

University of California

San Diego



SPN declares that he has no competing interests.

Paul Hamilton, MD


Department of Emergency Medicine

Mount Sinai School of Medicine

New York



PH declares that he has no competing interests.

Ruben Thanacoody, MD, FRCP(Edin)

Consultant Physician and Clinical Toxicologist

Regional Drugs and Therapeutics Centre




RT declares that he has no competing interests.

  • Differentials

    • Viral infection
    • Alcohol intoxication
    • Migraine
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  • Guidelines

    • Clinical guidance for carbon monoxide (CO) poisoning
    • Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with acute carbon monoxide poisoning
    More Guidelines
  • Patient leaflets

    Carbon monoxide poisoning

    More Patient leaflets
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