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Chemical Warfare: Trauma and Emergency Education

Emergency Medicine

Authors

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Nelya Melnitchouk, MD, MSc, FACS
Author
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Vanessa Welten, MD, MPH
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Definition

Chemical warfare has historically been used by both military and terrorist groups to target the civilian population of the opposing side.
Chemical attacks are often sudden, lethal, and difficult to identify, making reliable detection, triage, and management crucial to the survival of those who are affected.

Detection of Chemical Attacks

Chemical attacks may be difficult to identify by first responders and victims alike. Most of the recent chemical attacks have been performed using odorless and colorless gasses, making detection a difficult task.
When the chemical attack initially occurs, first responders will likely be unaware of the identity of the agent(s) unless prior knowledge was gained from intelligence sources. It will also take time to gain identification from laboratory analysis.
There are several different techniques for field detection of agents. All of these tests can potentially yield false negatives (lack of agent detection when the agent is in fact present) and false positives (agent detected when in fact agent was not present).
It should be noted that portable detection agents developed for military use can potentially give inaccurate responses in civilian scenarios.
Symptoms displayed by victims will generally guide initial management until definitive test results have been reported.

Types of Chemical Weapons

Chemical weapons can be divided into 7 distinct categories:
  1. nerve agents
  2. vesicants (blister agents)
  3. blood agents (cyanide compounds)
  4. pulmonary agents
  5. riot control agents (tear gasses)
  6. psychotomimetic agents
  7. toxins (biological origin).
Nerve Agents
In modern times, nerve agents are among the most frequently used chemical weapons. Nerve agents are highly toxic and cause death within several minutes of exposure.
Two of the most common types of nerve agents, G (Sarin) and V (VX) also have distinct odors, with G agents producing a fruit-like odor and V agents producing an amine-like odor (smell of raw fish). G agents tend to act through inhalation, while V agents tend to act via skin penetration.
At room temperature, they exist as odorless liquids, that may be colorless or yellow-brown. However, if used in an explosive device these would become a gas.
Exposure symptoms include, by system:
  • Eye:
    • Constriction of the pupil
    • Dim vision
    • Red eye, with clearly visible red blood vessels
    • Tears
  • Mouth, Nose, and Throat:
    • Runny nose
    • Excess drooling
    • Coughing up mucus
    • Difficulty breathing
  • Gastrointestinal and Genitalia:
    • Nausea
    • Vomiting
    • Abdominal pain and cramps
    • Diarrhea
    • Involuntary urination
  • Other:
    • Slower and irregular heart rate
    • Headache
    • Muscle twitching
    • Muscle paralysis
    • Convulsions
    • Tremors
    • Confusion
    • Sweating
Blood agents (cyanide compounds)
Blood agents work by affecting the body’s ability to supply the tissues and organs with oxygen, causing rapid decline and death in those exposed. The chemical weapons are mainly based on cyanide and include hydrogen cyanide (HCN) and cyanogen chloride (CNCl).
Absorption of blood agents is mostly via inhalation, but skin absorption can also occur. Typically, these agents have a bitter almond odor (Hydrogen Cyanide), though cyanogen chloride also has a strong odor. However, 20-50% of population is unable to detect the odor. At room temperature, hydrogen cyanide is a colorless or pale blue liquid, and cyanogen cyanide is a colorless gas.
Affected patients often unexpectedly and suddenly collapse due to loss of consciousness and/or convulsions. Symptoms generally have immediate onset.
Exposure symptoms include, by system:
  • Nervous system
    • Headache
    • Confusion
    • Drowsiness
    • Seizures
    • Convulsions
  • Respiratory
    • Difficulty breathing
    • Higher rate of shallow breaths
    • Lower rate of breathing at later exposure
  • Cardiovascular
    • Higher heart rate
    • High blood pressure
    • Abnormal heart rhythm
  • GI
    • Nausea
    • Vomiting
  • Other
    • Sweating
    • Bright red skin
    • Blueness on fingertips and lips
    • Dilated pupils
    • Irritated eyes
Choking agents
Choking agents work by affecting the nose, throat, and lungs of those exposed. This type of chemical weapon can cause inflammation and buildup of fluid in the lungs, which results in difficulty breathing. Common choking agents include chlorine and phosgene-derived compounds. Toxic compounds which appear in smoke (from fires) have similar effects to choking agents.
At room temperature, chocking agents are generally colorless gasses and liquids. Chlorine is a green-yellow gas and clear amber-colored liquid. Gasses may have a smell (e.g. phosgene smell resembles freshly mown hay), but the odor is weak and is often imperceptible .
Symptoms are mostly respiratory, caused by buildup of fluid in the lungs. If an exposed individual survives, symptoms generally begin to resolve within 48 hours, with little to no residual damage if there is no complicating infection.
Exposure symptoms include, by system:
  • Respiratory
    • Red frothy fluid coming out of mouth and nostrils
    • Collapsed lung (causing chest pain, difficulty breathing, and cough)
    • Difficulty breathing
    • Shortness of breath (delayed)
    • Increased susceptibility to respiratory infection
  • Other
    • Burning sensation in eyes
    • Tears in eyes
    • Cough
    • Pressure and tightness in lower chest
    • Blue color on lips and fingertips
    • Hypotension
Vesicants (Blister Agents)
Vesicant agents include sulfur mustard, nitrogen mustard, arsenic, as well as halogenated oximes. They will burn and blister any part of the body they contact, including the:
  • Skin
  • Eyes
  • Mucous membranes
  • Lungs
  • Blood-forming organs
Exposure symptoms include, by system:
  • Skin
    • Initial exposure: similar to sunburn
      • superficial reddening of skin (erythema)
      • Edema (swelling)
      • Intense itching
    • Erythema is followed by blisters
      • Fragile; can easily rupture
      • Non-painful
      • Groups of new blisters can appear up to the second week after exposure
      • Blister fluid does not cause secondary blistering
    • Severe exposure can cause deep burning with complete loss of skin
      • More likely to occur on eyelids, penis, scrotum
      • Regeneration of skin is much slower than damage from physical means
      • Underlying muscle and blood vessels may be severely damaged
  • Respiratory
    • After a latent period of 4-8 hrs, causes congestion in throat and nose
    • Symptoms:
      • Runny nose
      • Burning pain in throat
      • Hoarse voice
      • Cough (both dry and with mucus)
      • Rales detected by auscultation
      • Difficulty breathing
      • Increased susceptibility to respiratory infection (bronchopneumonia often occurs after 48 hrs)
  • Eye
    • Lewisite agents cause severe damage to the eye
      • Edema (swelling) of lids that causes closure of eye
      • Hazy cornea after a few hours
      • Secondary infection may result
      • Severe exposure can cause blindness
  • GI:
    • Vomiting
    • Nausea
    • Diarrhea
    • Abdominal pain
  • Other
    • Headache
Riot Control Agents (Tear Gasses)
Riot control agents are commonly used in the suppression of civil unrest by security forces. As such, they generally have low toxicity, rapid onset, and a short duration of action. Common examples include CS gas, CN gas, and pepper spray.
Though CS and CN gasses are usually sprayed in an aerosol form or as a solution, they have a solid appearance at room temperature.
Exposure symptoms include, by system:
  • Eyes
    • Burning sensation in eyes
    • Pink appearance in eye
    • Redness in eyelids
    • Contraction if eyelid muscles
    • Tears in eyes
    • Sensitivity to light
  • Respiratory
    • Burning sensation and pain in throat and nose
    • Runny nose
    • Mild nosebleed
    • Sneezing
    • Coughing
    • Choking sensation
  • Skin
    • Burning sensation on skin
    • Redness on skin
    • Blister formation
  • Other
    • Diarrhea
    • Headache
    • Nausea
Toxins (Biological Origin)
Toxins are produced by biological organisms such as bacteria, fungi, animals, or plants. They include an incredibly wide range of substances. This guide will only discuss ricin and saxitoxin, two agents which have been listed on Schedule 1 of the Chemical Weapons Convention, which is a list of chemicals often used in chemical warfare.
Individuals can be exposed to both these agents by inhalation, oral consumption, or injection.
Ricin exposure symptoms, by route of exposure:
  • GI (if consumed)
    • Nausea
    • Vomiting
    • Abdominal pain and cramps
    • Diarrhea
    • Blood leakage from anus
    • Tarry stool
    • Blood in stool
  • Respiratory (if inhaled)
    • Difficulty breathing
  • Other
    • Dilation of pupils
    • Headache
    • Thirst
    • Fever
    • Pain (especially in injection site if injected)
    • Low blood pressure
    • Blueness on fingernails and lips
Saxitoxin symptoms are similar to Ricin exposure symptoms, but also includes severe muscle paralysis.

General guidelines on protective equipment

Personal protective equipment (PPE) is considered the first line of defense against chemical weapons.
PPE includes: a mask or respirator, eye protection, and protective clothing.
Ordinary clothing generally does not provide adequate protection from agents that harm the skin. However, if no alternatives are available, it is advised to cover nose and mouth through any available means to limit exposure.

General guidelines on exposure management

It is critical to remove the chemical agent from the vicinity of the victim as soon as possible. This is accomplished via physical removal or chemical inactivation.
For those in the affected area, leave the area exposed to the chemical weapon as soon as possible to limit one’s exposure. It is also important to seek medical attention as soon as possible.
80% of decontamination includes removal of clothes, as well as any jewelry or watches. Water and soap should be used liberally to clean the skin and hair, using repeated cycles of rinsing and wiping; insufficient water use may only disperse agent over skin. Wounds should be cleaned by 0.9% saline solution, if available. Agents that cause eye irritation should be managed by removing contact lenses, and flushing out the eyes with water or 0.9% saline solution.
To prevent further spread of chemical agents, especially to healthcare personnel, no person leaving the site of a chemical attack should be permitted to exit without going through an established decontamination station. Healthcare personnel working at these stations should wear head-to-toe PPE, even if they do not enter the immediate site of the attack.
Separate lines should be set up for patients who can walk without assistance, and patients who are non-mobile.

Exposure interventions

Skin
Following initial exposure, it is important to remove any contaminants from the skin using water or any moisturized wipes or cloths if available.
Blisters and other wounds on skin should be covered with dressings (sterile in possible), with regular inspection to monitor progression of injury.
Burns involving a large area may cause significant electrolyte and organ injuryrequiring long-term care and management by a medical institution.
Respiratory
An individual with a lot of mouth secretions should be placed in the what is termed the “recovery position” (Picture). In this position, the individual’s head rests on their arm on the ground, and their top knee is brought over to be leaned on keep the patient on their side, like an easel. This position help keep the individual’s airway open. It also prevents them from choking on vomit or saliva. In this position, continue to assess for breathing and call for help if able.
For any patient found down, ensure the ABCs – airway, breathing and circulation (see the “patient found down” article for more information). Do not insert anything in the victim’s mouth due to possible damage to the throat from the chemical agent.
If possible, secretions in the mouth and throat should be suctioned out to prevent blockage.
Emergency medical providers may utilize devices that provide oxygen or positive airway pressure (such as a bag-valve mask device) for victims having difficulty breathing due to fluid buildup in the lungs. Patients dealing with low oxygen levels (hypoxia), as evidenced by blueness of fingertips or lips, may benefit from oxygen therapy.

References:

  1. Ganesan K, Raza SK, Vijayaraghavan R. Chemical warfare agents. J Pharm Bioallied Sci. 2010;2(3):166-178. doi:10.4103/0975-7406.68498
  2. Practical Guide for Medical Management of Chemical Warfare casualties. Organisation for the Prohibition of Chemical Weapons. https://www.opcw.org/sites/default/files/documents/ICA/APB/Practical_Guide_for_Medical_Management_of_Chemical_Warfare_Casualties_-_web.pdf. Accessed June 16, 2022.
  3. Hydrogen cyanide (AC): Systemic agent. Centers for Disease Control and Prevention. https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750038.html. Published May 12, 2011. Accessed June 16, 2022.