TOXICOLOGY/ADDICTION MEDICINE
Silent Killers in the Smoke: Recognizing and Managing Carbon Monoxide and Cyanide Poisoning in House Fires By Christina Tang, PharmD, and Kevin J. Mercer, PharmD, MPH, on behalf of the SAEM Toxicology Interest Group House fires present significant challenges in emergency medicine, as they can lead to not only visible burn injuries but also hidden dangers like carbon monoxide (CO) and cyanide poisoning.1 These toxic agents, often encountered together in fire-related emergencies, require swift recognition and treatment to prevent severe morbidity and mortality.
Pathophysiology and Toxicity
Carbon monoxide is a colorless, odorless gas produced by the incomplete combustion of carboncontaining materials. It can be found in fires caused by common
household items, including gas fires, overloaded outlets, portable heaters, and charcoal grills. Carbon monoxide binds to hemoglobin, forming carboxyhemoglobin (COHb), which reduces the blood's oxygen-carrying capacity and impairs tissue oxygen delivery (See Figure 1), leading to cellular hypoxia. Hydrogen cyanide is also an odorless gas produced by the combustion of everyday items such as carpeting, upholstery, plastics, wood, cotton, and paper. Cyanide inhibits cytochrome c oxidase in the mitochondrial electron transport
chain, halting cellular respiration and forcing cells into anaerobic metabolism. This process results in lactic acidosis, cellular death, and multisystem organ failure, with rapid onset of symptoms like altered mental status and cardiovascular collapse.
Clinical Presentation
Early recognition of carbon monoxide and cyanide toxicity is critical for initiating prompt treatment; however, diagnosing both conditions can be challenging without a high
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