White 2002 - Chemical and biological weapons Flashcards
Summarise White 2002
Published in BJA
Commentary on chemical and biological agents and their treatment
Covers:
- Factors affecting the severity of an attack
- Initial management of casualties
- Agents
- Chemical and biological weapons
- Biological weapons
- Conclusions
Odd paper very focussed on anaesthetists
Discuss the initial management of casualties in a CBW attack
Triage
- Discusses triage classifications
- Classifications can change
Decontamination
- Ambulance reception area
- Showers or specific treatments
- Need full PPE
Table 1 shows various weapons and their decontamination/PPE requirements
Protection of staff
- Decontamination prior to arrival
- PPE
- Isolation
What factors affect the casualty rate of a CBW attack as per White 2002?
As shown in figure 1
Deployment
Agent
Population
Outline the types of chemical agents used in CBW attacks from White 2002
Any chemical can be used but some have been designed for the job
Nerve agents (eg sarin, VX)
- Extremely toxic
- Odourless, tasteless, colourless
- Cholinesterase inhibitors
- Atropine and pralidoxime
Blistering agents (eg. mustard gas)
- chemical burns and blistering
- Respiratory failure, blindness, vomiting
Choking agents (eg. Chlorine, phosgene)
- Respiratory distress then toxic pulmonary oedema
Blood agents (eg. hydrogen cyanide)
- inhibit cytochrome oxidases etc
- metabolic acidosis, hypoxia and cardiac arrest
Toxins (eg. botulinium)
Tear gas
- Sensory irritants
- Often death occurs due to accident while incapacitated
Outline the nature of biological agents used in CBW attacks from White 2002
Low dose release into unprotected population with low immunity
Consistent rapid, high rate of fatality
Easy to mass produce
Difficult to treat
Outline the nature of toxin agents used in CBW attacks from White 2002
Only 17 have the utility to be used on the battlefield
Includes
Botulininum, Ricin, Saxitoxin
Botulinum:
- More toxic than sarin
- Permanent inhibition of acetylecholine release
- Presents 1-4 days post exposure
- Bulbar palsy followed by symmetrical descending weakness and resp failure
- Week to months of supportive treatment
- Antitoxin available but efficacy unknown
Ricin
- Easily produced from commercial production of castor oil
- Abdo pain and diarrhoea
- Inhalation rapidly fatal
- Supportive treatment
- Interrupts protein synthesis
Saxitoxin
- Found in shellfish
- 20 times more lethal than sarin
- Inhibitor of sodium channels
- GI upset then bulbar palsy and respiratory and cardiovascular failure
- Supportive treatment
Outline the nature of nerve agents used in CBW incidents as per White 2002
Highly potent anticholinesterases
Related to organophosphates
Acetylcholine accumulates at muscarinic, nicotinic and CNS synapses
Salivation, bradycardia, miosis, vomiting, urinary and faecal incontinence
Weakness and paralysis
Incapacitates in 1-10 mins, death in 1-15 mins
Worse if inhaled
Triphasic clinical syndrome
1. Cholinergic phase
2. Intermediate syndrome
3. Delayed polyneuropathy
Treatments:
Pyridostigmine - pretreatment
Atropine - antagonises muscarinic effects
Oximes - reverse nicotinic effects
Outline the types of blood agents used in CBW attacks from White 2002
Hydrogen cyanide and cyanogen chloride
Metabolic poisons
Fatal within 15 minutes
Dizziness, confusion, tachypnoea following by seizure, coma and arrest
Sodium thiosulphate and sodium nitrate
Outline the types of blistering agents used in CBW attacks from White 2002
Arsenicals and mustards
Mustard gas odourless at lethal concentrations
Latent period followed by symptoms
Diffuse cutaneous oedema with first degree burns
Manage as burns
Ocular symptoms very common - delayed onset eye pain, blurred vision and lacrimation
Copious irrigation with saline
Respiratory symptoms, sloughed respiratory epithelium
May need ventilation
Bone marrow supression - primarily leukopenia, with anaemia and thrombocytopenia
Sodium thiosulphate, vitamin E, dexamethasone
Outline the types of choking agents used in CBW attacks from White 2002
Chlorine and phosgene
Both mediate by formation of hydrochloric acid
Chlorine tends to affect eyes
Phosgene works its way into lower airways causing severe pulmonary oedema
Supportive management
Cortiosteroids
Outline the types of biological weapons used in CBW attacks from White 2002
Anthrax
- Three presentations
- Cutaneous - pruritic papules, vesicles then gross oedema
- Gastrointestinal - GI ulcers and GI Bleeding
- Systemic - malaise, fatigue, myalgia
- Cipro and doxy
Plague
- Bubonic/pneumonic
- Streptomycin/gent/doxy/chloramphenicol
VHF
- Multiple pathogens
- Malaise followed by vasculopathy and coagulopathy
Supportive treatment
Viral encephalitis
Tularaemia
Smallpox
Glanders
Q fever
