Blistering agents-toxicology. Characteristics. Medical activities
Written by Anam Hussain
General characteristics:
- Blistering agents are chemical compounds created as chemical weapons
- Intracellular poisons
- Mainly affect skin due to solubility in organic fat
- rapidly absorbed
- cause systemic damage
- main representatives of this group are: Sulphur mustard, Lewisite, phosgene oxime
- Sulphur mustard gas:
- is oily liquid with low volatility art cool temperatures
- vaporises rapidly in hotter climates
- yellow in colour and smells similar to garlic
- well dissolved in organic solvents: alcohol, ether, benzene, veg and animal fats
- all symptoms to sulphur mustard exposure are delayed with onset
- Lewisite:
- Is oily, colourless liquid
- Characteristic odour of geranium
- More volatile and persistent at cooler temperatures than sulphur mustard
- Lethal dose is 2g
- Symptoms occur immediately after exposure
- Phosgene oxime:
- Yellowish-brown liquid
- Does not produce vesicles on skin (as mustard and Lewisite)
- Acts as a nettle agent
- Able to penetrate garments and rubber
- Symptoms occur immediately after exposure
Pathophysiology:
- Intoxication with blistering agents occurs via all routes of exposure
- They are intracellular poisons due to their high solubility in fat and ability to penetrate cellular membranes
- In cells they undergo a cyclisation process
- Emerging onium compounds react with active groups of proteins and nucleoproteins and other cellular organelles
- Main damaging effect is depolymerization of DNA resulting in distortion in mitosis and pronounced effect on tissues with high regeneration activity
Clinical symptoms:
Symptoms in case of dermal exposure
- Visible erythema 4-8hrs after exposure
- Development of vesicle from erythema within 12-18hrs
- Vesicles transform into blisters across a few days
- Blisters replaced with superficial translucent lesions
- Lewisite exposure causes immediate pain and central blistering
Symptoms in case of ocular exposure
- Tearing, conjunctivitis
- eyelid oedema, Corneal oedema
- ocular damages from lewisite are less severe due to blepharospasm, which prevents further exposure
Symptoms in case of inhalation
- Sore throat, hoarseness, cough
- Bronchospasm, dyspnoea
- Haemorrhagic bronchitis
Symptoms in case of ingestion
- vomiting (not usually a prominent symptom)
Systemic effects:
- Leukocytopenia, pancytopenia after exposure to Sulphur mustard
General toxicity symptoms:
- Disorders of the nervous system
- Mental motor excitement
- Memory impairment
- Convulsions
- Loss of consciousness with intoxications at high dose
Medical Activities
- First aid and first medical aid is provided in case of intoxication
- AOD abandoned immediately due to lack of protection available as clothing
- No Antidote available for Sulphur mustard or phosphene oxime exposure. Sulphur mustard is heavier than air and will settle to ground very quickly
- If exposure to sulphur mustard has occurred, perform partial decontamination