Carbon monoxide poisoning.

Carbon monoxide (CO) is a ubiquitous toxin that may reversibly bind various heme-containing proteins in the human body. These proteins (hemoglobin, myoglobin, cytochrome P450, cytochrome oxidase) may be bound by the CO at sites which are also responsible for O2 transport. Since the CO-heme bond is less dissociable than the O2-heme bond, severe disruption of normal O2 transport may occur. A tissue hypoxia may result causing transient or permanent damage that may appear as clinical abnormalities. Since the clinical effects of exposure are the result of local hypoxia, they tend to appear in the more oxygen dependent tissues such as the brain and heart. Specific treatment for the exposure consists of restoring O2 supplies to the deprived tissues and supporting the patient through the short and long term sequellae of the hypoxia. Since a wide variety of CO sources may cause the intoxication and the clinical presentation may mimick other diseases, medical personnel must be alert to this relatively common illness.