Cyanogen Chloride Poisoning
- Author: Heather Murphy-Lavoie, MD, FAAEM; Chief Editor: Robert G Darling, MD, FACEP more...
Background
Cyanogen chloride (North Atlantic Treaty Organization [NATO] designation "CK") is 1 of 2 volatile cyanide military chemical warfare agents. The other similar agent is hydrogen cyanide, or AC. These agents first were used in large quantities by the French and British during World War I. Although the United States maintained 500-pound and 1000-pound cyanogen chloride (CK) bombs, these were not used during World War II. More recently, Iraq is suspected to have used a cyanidelike agent against the Kurds in the 1980s.
Cyanogen chloride vs hydrogen cyanide
Although cyanogen chloride (CK) and hydrogen cyanide (AC) are similar in their toxicity, a few important differences exist. Firstly, cyanogen chloride (CK) is less volatile than hydrogen cyanide (AC), making it more effective at low concentrations. Secondly, by nature of its chlorine moiety, cyanogen chloride (CK) causes irritation of the eyes and respiratory tract and potential delayed pulmonary toxicity similar to chlorine or phosgene gases. In high concentrations (eg, in enclosed spaces), this agent is rapidly acting and lethal, causing death within 6-8 minutes if inhaled at doses at or above its LCt50 (ie, lethal concentration that kills 50% of people) (11,000 mg·min/m3).
Cyanogen chloride and cyanide poisoning
Cyanogen chloride (CK) is synthesized in the United States for industry by Matheson Tri-Gas and is used as an organic precursor and in mining and metalworking. Therefore, an emergency physician may be more likely to encounter cyanogen chloride (CK)–exposed victims following an industrial accident rather than in a warfare or terrorism scenario.
The major source of cyanide poisoning in the United States does not come from cyanogen chloride (CK) but rather from smoke inhalation during house and/or industrial fires in which plastics (acrylonitriles, polyurethanes), wool, or silk are burned.[1, 2] Cyanide poisoning is also found in association with chemical synthesis, electroplating, mineral extraction, dyeing, photography, and agriculture.
See also Cyanide Toxicity, Hydrogen Cyanide Poisoning, as well as other topics in Warfare - Chemical, Biological, Radiological, Nuclear and Explosives.
Etiology and Pathophysiology
Other than acts of terrorism or war, a mass casualty may develop in an industrial accident in which cyanogen chloride (CK) comes in contact with water (eg, during a fire-fighting expedition). Containers of cyanogen chloride (CK) may rupture or explode if exposed to high heat or following prolonged storage.
In addition to the local irritant effects of cyanogen chloride (CK), systemic toxicity occurs through mechanisms similar to those seen with hydrogen cyanide (AC) exposure.[3] Cyanogen chloride (CK) liberates a cyanide molecule, which enters the blood stream and distributes to tissues.[4] Once inside cells, cyanogen chloride (CK) binds to mitochondrial cytochrome aa3, interrupts electron transport, and creates imbalance between ATP synthesis and hydrolysis. Oxygen is unable to be used effectively as the terminal electron acceptor, which forces a shift to anaerobic metabolism. Although all organ systems are impacted, the most oxygen-dependent organs are the most affected (ie, brain, heart).
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