How does carbon monoxide (CO) cause harm to the brain?

Updated: Sep 18, 2018
  • Author: Guy N Shochat, MD; Chief Editor: Gil Z Shlamovitz, MD, FACEP  more...
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Answer

Studies have indicated that CO may cause brain lipid peroxidation and leukocyte-mediated inflammatory changes in the brain, a process that may be inhibited by hyperbaric oxygen therapy. Following severe intoxication, patients display central nervous system (CNS) pathology, including white matter demyelination. This leads to edema and focal areas of necrosis, typically of the bilateral globus pallidus. Interestingly, the pallidus lesions, as well as the other lesions, are watershed area tissues with relatively low oxygen demand, suggesting elements of hypoperfusion and hypoxia. [8]

Studies have demonstrated release of nitric oxide free radicals (implicated in the pathophysiology of atherosclerosis) from platelet and vascular endothelium, following exposure to CO concentrations of 100 ppm. One study suggests a direct toxicity of CO on myocardium that is separate from the effect of hypoxia. [9]

HbCO levels often do not reflect the clinical picture, yet symptoms typically begin with headaches at levels around 10%. Levels of 50-70% may result in seizure, coma, and fatality.


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