Chemical weapons: Difference between revisions
(20 intermediate revisions by 5 users not shown)
Line 1: Line 1:
==Background==
==Background==
'''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.
*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.   
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.
 
===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


==Types==
==Types==
*[[Blister chemical agents]] (Vesicants)
{{Chemical weapon DDX}}
**Lewisite (L)
**Sulfur mustard (H)
**Phosgene oxide (CX)
*[[Pulmonary chemical agents]]
**Ammonia
**Methyl isocyanate
**methyl bromide
**Hydrochloric acid
**Chlorine
**Pphosgene
*Incendiary Agents
**Agent Orange
**[[White phosphorus]]


== [[Cyanide]] Agents (CN) ==
==[[Cyanide]] Agents (CN)==
*AKA Hydrocyanic acid, Formonitrile, Prussic acid
*AKA Hydrocyanic acid, Formonitrile, Prussic acid
*Mimics carbon monoxide poisoning
*Mimics carbon monoxide poisoning
Line 27: Line 18:
*Can penetrate rubber and barrier fabrics
*Can penetrate rubber and barrier fabrics


=== Pathophysiology ===
===Pathophysiology===
*Cyanide inhibits cytochrome oxidase on mitochondria
*Cyanide inhibits cytochrome oxidase on mitochondria
*Cells unable to use oxygen in bloodstream
*Cells unable to use oxygen in bloodstream
*Cellular asphyxiation
*Cellular asphyxiation


=== Symptoms ===
===Symptoms===
*Symptoms can be delayed up to 60 minutes
*Symptoms can be delayed up to 60 minutes
*Symptoms dependent on concentration, form of cyanide, and route of exposure
*Symptoms dependent on concentration, form of cyanide, and route of exposure
Line 39: Line 30:
*Anxiety, dizziness, headache, apnea, seizures, and coma  
*Anxiety, dizziness, headache, apnea, seizures, and coma  


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


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


=== Pathophysiology ===
===Pathophysiology===
*Acetylcholinesterase inhibitors causing excess acetylcholine at nicotinic and muscarinic receptors
*Inhibits acetylcholinesterase → excess acetylcholine at both nicotinic and muscarinic receptors


=== Symptoms ===
===Symptoms===
*DUMBELLS  
*DUMBELLS
**D-Diarrhea, U-Urination, M-Miosis, B-Bronchorrhea/Bradycardia, E-Emesis, L-Lacrimation, S-Salivation/Seizures
**D-Diarrhea, U-Urination, M-Miosis, B-Bronchorrhea/Bradycardia, E-Emesis, L-Lacrimation, S-Salivation/Seizures
*Cholinergic toxidrome [[Toxidromes]]
*Cholinergic toxidrome [[Toxidromes]]


=== Treatment ===
===Management===
*Nerve agents prolong succinylcholine's paralytic effect
*Nerve agents prolong succinylcholine's paralytic effect
*Atropine for bronchorrhea and bronchoconstriction, no max dose
*Atropine for bronchorrhea and bronchoconstriction
*Pralidoxime to restore function of acetylcholinesterase (given over approx 30 minutes; rapid infusion can cause HTN)
**Start at 2-6mg, double the dose q5-30min until control of secretions (no max dose)
*Pralidoxime to restore function of acetylcholinesterase (given over approximately 30 minutes; rapid infusion can cause hypertension)
**Give as soon as possible - must be given before "aging" occurs to be effective
*Benzodiazepines for seizures (standard AEDs may be ineffective)
*Benzodiazepines for seizures (standard AEDs may be ineffective)
*Mark 1 Nerve Agent antidote Kit (NAAK): 2 autoinjectors:   
*Mark 1 Nerve Agent antidote Kit (NAAK): 2 autoinjectors:   
Line 76: Line 68:
**600mg pralidoxime
**600mg pralidoxime
*DuoDote Autoinjector: 2.1mg atropine, 600mg pralidoxime in one autoinjector
*DuoDote Autoinjector: 2.1mg atropine, 600mg pralidoxime in one autoinjector
*Prophylaxis in the military, high risk setting with [[pyridostigmine]]
**Reversibly bind acetylcholinesterase before exposure to nerve agents
**[[Pyridostigmine]] 30 mg PO q8<ref>Dunn MA, Sidell FR. Progress in medical defense against nerve agents. JAMA. 1989;262:649–652.</ref>
==Differential Diagnosis==
{{MCI types}}


== Pediatric considerations ==
==Management==
*Higher metabolic rate and faster basal respiratory rate, causing more rapid and larger exposures
*Depends on specific agent used
*Skin is thinner and more permeable
*Regardless of agent, Decontamination and ABCs are of primary importance
*Agents heavier than air have increased concentrations closer to the ground exposing children > adults
**Use appropriate personal protective equipment (PPE)
**Decontamination (should take place pre-hospital or otherwise prior to entering the ED)
***Remove all patient clothing
***Brush off dry agent (e.g. powders), copiously irrigate skin of any liquid contaminant


==See Also==
==See Also==
*[[Toxicology (Main)]]
*[[Toxicology (Main)]]
*[[Weapon of mass destruction]]
*[[Hazmat exposure]]


== References ==
==References==
#’’Basic Disaster Life Support V.3.0 Course Manual.’’ N.p.: American Medical Association, 2012. Print.
<references/>
#’’Campbell, John E. Tactical Medicine Essentials.’’ Sudbury, MA: Jones & Bartlett Learning, 2012. Print
#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.
#http://www.ncbi.nlm.nih.gov/pubmed/15094583


[[Category:Tox]][[Category:EMS]][[Category:Featured]]
[[Category:Toxicology]]
[[Category:EMS]]

Revision as of 18:20, 14 May 2018

Background

  • 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.

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

Types

Chemical weapons

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

Pathophysiology

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

Symptoms

  • 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

Management

  • 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)
    • G-series are volatile non-persistent agents that evaporate quickly
    • V-series high viscosity with oily consistency
  • Rapidly absorbed through skin, symptoms generally develop within 1 hour
  • Vapors are heavier than air and tend to sink into low places
  • Sarin used in Tokyo subway attack in 1995; 5,000 sought medical attention with 12 deaths.

Pathophysiology

  • Inhibits acetylcholinesterase → excess acetylcholine at both nicotinic and muscarinic receptors

Symptoms

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

Management

  • Nerve agents prolong succinylcholine's paralytic effect
  • Atropine for bronchorrhea and bronchoconstriction
    • Start at 2-6mg, double the dose q5-30min until control of secretions (no max dose)
  • Pralidoxime to restore function of acetylcholinesterase (given over approximately 30 minutes; rapid infusion can cause hypertension)
    • Give as soon as possible - must be given before "aging" occurs to be effective
  • 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
  • Prophylaxis in the military, high risk setting with pyridostigmine
    • Reversibly bind acetylcholinesterase before exposure to nerve agents
    • Pyridostigmine 30 mg PO q8[1]

Differential Diagnosis

Mass casualty incident

Management

  • Depends on specific agent used
  • Regardless of agent, Decontamination and ABCs are of primary importance
    • Use appropriate personal protective equipment (PPE)
    • Decontamination (should take place pre-hospital or otherwise prior to entering the ED)
      • Remove all patient clothing
      • Brush off dry agent (e.g. powders), copiously irrigate skin of any liquid contaminant

See Also

References

  1. ↑ Dunn MA, Sidell FR. Progress in medical defense against nerve agents. JAMA. 1989;262:649–652.
Retrieved from "https://www.wikem.org/w/index.php?title=Chemical_weapons&oldid=178637"