Description

A chemical weapon is any chemical agent used to cause intentional death or harm through its toxic properties. They often affect the CNS, pulmonary, cardiovascular, dermal, ocular, or GI systems. In addition, they tend to exert their effect rapidly, usually within minutes to hours. They can have a variety of physical properties including aerosol, vapor, gas, or liquid

Etiology

• Blood agents/chemical asphyxiants: Cyanide and cyanogens:
  • Inhibition of cellular respiration by binding to ferric ion in cytochrome oxidase a-a3 and uncoupling oxidative phosphorylation
• Vesicants: Sulfur mustard, nitrogen mustard, lewisite, phosgene oxime:
  • Alkylation and cross-linking of purine bases of DNA and amino acids resulting in change in structure of nucleic acid, proteins, and cellular membranes
  • Inhibits glycolysis leading to cellular necrosis
  • Induce blistering of the skin and mucous membranes
• Lacrimators and riot control agents: 1-chloroacetophenone (CN; Mace), o-chlorobenzylidene malononitrile (CS), oleoresin capsaicin-pepper spray (OC), chloropicrin, adamsite (DM):
  • Mucous membrane irritators
• Pulmonary irritants (choking agents): Ammonia, Chlorine, Phosgene:
  • Can cause delayed ARDS
  • High water solubility: Ammonia:
    • Mucous membrane irritation of eyes and upper airway
  • Intermediate water solubility: Chlorine:
    • Forms hydrochloric acid, hydrochlorous acids, which form free radicals causing upper airway and pulmonary irritation
  • Low water solubility: Phosgene:
    • Mild irritant effects initially, then delayed pulmonary edema as late as 24 hr
    • Direct pulmonary damage after hydrolysis in lungs to hydrochloric acid
• Nerve agents: Sarin, tabun, soman, VX
  • Cholinesterase inhibitors – causes cholinergic overstimulation at muscarinic, nicotinic, and CNS sites
• Incapacitating agents: 3-quinuclidinyl benzilate (BZ):
  • Anticholinergic (antimuscarinic) effects