Chemical weapons

Revision as of 23:30, 7 October 2014 by Rossdonaldson1 (talk | contribs)


Chemical agents can be released via unintended means such as a spill from a damaged railroad tank car or industrial explosion as well as by intentional means as chemical weapons. If concern for chemical exposure exists, appropriate personal protective equipment (PPE) should be worn by first responders and everyone involved to prevent further casualties. Initial management of a patient with a chemical exposure includes decontamination as it prevents further damage from the exposure as well as protects others from contamination. Aggressive management of the airway, breathing, and circulation (ABCs) should be undertaken in all cases of critically ill chemical exposure.


Choking/Pulmonary Agents

  • Ammonia, methyl isocyanate, methyl bromide, hydrochloric acid and chlorine, phosgene
  • Common toxic industrial chemicals, transported widely across country
  • Can affect central or peripheral airways
    • burning and irritation to epithelial lining causing airway edema or pulmonary edema, hypoxia, and hypotension


  • Smells of a swimming pool or bleach
  • Most common exposure is secondary to mixing household cleaners
  • Irritation of conjunctivae, nose, pharynx, larynx, trachea, and bronchi
  • Individuals with gas exposure may not need decon, if skin symptoms absent
  • Rare ocular injury as tears protect mucous membranes from direct damage


  • Smell of freshly cut hay or grass
  • Not to be confused with phosgene oxide (vesicant)
  • Denser than air, settles in low-lying places – trenches/basements
  • Rapid olfactory fatigue can occur leading to prolonged exposure
  • Exposure may be secondary to fire at textile factory/house, metalwork, or burning Freon
  • Symptoms dependent on concentration
    • Low: mild cough, chest tightness, shortness of breath
    • Moderate: Lacrimation
    • High: Non-cardiogenic pulmonary edema within 2 to 6 hours after exposure with death within 24-48 hours
  • Symptoms may take 2-24 hours to develop


  • Choking agents combine with water in respiratory tract to form acids
  • Both chlorine and phosgene react with water in respiratory tract to form hydrochloric acid


Symptoms dependent on the water solubility of the chemical

  • Highly water-soluble
    • Anhydrous, ammonia, Hydrogen chloride, Sulfur dioxide, Formaldehyde
    • Rapidly react with water causing damage to upper airway to vocal cords
    • Direct tissue damage causing edema/airway obstruction and laryngospasm
  • Moderately water-soluble
    • Damage to moderate-sized airways (bronchioles)
    • Bronchospasm and wheezing
  • Poorly water-soluble
    • Phosgene, Nitrogen dioxide
    • Inhaled deeply into alveoli
    • Lack of irritation of mucous membranes can cause them to go undetected


  • Liquid phosgene can cause off-gassing with release of toxin from clothes post-exposure
  • Do not allow patient to be active as it worsens condition
  • Diuretics and corticosteroids not shown to be effective
  • Inhaled beta agonists for bronchoconstriction

Cyanide Agents (CN)

  • AKA Hydrocyanic acid, Formonitrile, Prussic acid
  • Mimics carbon monoxide poisoning
  • Smell of bitter almonds but not all people can smell cyanide
  • Absorbed through skin, inhaled or ingested
  • Can affect individuals near fire with synthetic materials or plastics
  • Can penetrate rubber and barrier fabrics


  • Cyanide inhibits cytochrome oxidase on mitochondria
  • Cells unable to use oxygen in bloodstream
  • Cellular asphyxiation


  • Symptoms can be delayed up to 60 minutes
  • Symptoms dependent on concentration, form of cyanide, and route of exposure
  • CNS and cardiovascular system most susceptible
  • Initially hypertension and tachycardia progressing to bradycardia, hypotension, and arrhythmias late
  • Anxiety, dizziness, headache, apnea, seizures, and coma


  • 100% oxygen and antidote therapy
  • Sodium nitrite (IV) or amyl nitrite (inhaled) to displace cyanide from cytochrome oxidase
  • Sodium thiosulfate: For conversion of cyanide to excretable thiosulfate
  • Repeat sodium nitrite and sodium thiosulfate in 30min at half initial dose if needed
  • Hydroxocobalamin (Vit B12a): makes CN water soluble and non-toxic
  • Cyanide Antidote Kit: Amyl nitrite pearls, sodium nitrite (IV), sodium thiosulfate (IV)
  • Cyanokit: Less toxic than cyanide antidote kit and shown effective in cardiac arrest

Nerve Agents

  • Acetylcholinesterase inhibitors
  • Includes household and commercial pesticides (diazinon and parathion)
  • G-series (sarin, tabun, soman) and V-series (VX)
  • Rapidly absorbed through skin
  • Vapors are heavier than air and tend to sink into low places
  • G-series are volatile non-persistent agents that evaporate quickly
  • V-series high viscosity with oily consistency
  • Exposure to volatile agent, symptoms can develop within 1 hour
  • Sarin used in Tokyo subway attack in 1995; 5,000 sought medical attention with 12 deaths.


  • Acetylcholinesterase inhibitors causing excess acetylcholine at nicotinic and muscarinic receptors


    • D-Diarrhea, U-Urination, M-Miosis, B-Bronchorrhea/Bradycardia, E-Emesis, L-Lacrimation, S-Salivation/Seizures
  • Cholinergic toxidrome Toxidromes


  • Nerve agents prolong succinylcholine's paralytic effect
  • Atropine for bronchorrhea and bronchoconstriction, no max dose
  • Pralidoxime to restore function of acetylcholinesterase (given over approx 30 minutes; rapid infusion can cause HTN)
  • Benzodiazepines for seizures (standard AEDs may be ineffective)
  • Mark 1 Nerve Agent antidote Kit (NAAK): 2 autoinjectors:
    • 2mg atropine
    • 600mg pralidoxime
  • DuoDote Autoinjector: 2.1mg atropine, 600mg pralidoxime in one autoinjector

Pediatric considerations

  • Higher metabolic rate and faster basal respiratory rate, causing more rapid and larger exposures
  • Skin is thinner and more permeable
  • Agents heavier than air have increased concentrations closer to the ground exposing children > adults

Incendiary Agents

See Also


  1. ’’Basic Disaster Life Support V.3.0 Course Manual.’’ N.p.: American Medical Association, 2012. Print.
  2. ’’Campbell, John E. Tactical Medicine Essentials.’’ Sudbury, MA: Jones & Bartlett Learning, 2012. Print
  3. Schultz, Carl, and Kristi Koenig. “Weapons of Mass Destruction.” ‘’Rosen's Emergency Medicine Concepts and Clinical Practice.’’ By John A. Marx, Robert S. Hockberger, Ron M. Walls, James Adams, and Peter Rosen. 8th ed. Philadelphia: Mosby/Elsevier, 2013. N. pag. Print.