Nerve Gas

1
Nerve Gas

• Stevan Cordas DO MPH
• Committee on Bioterrorism - Texas Department of
  Health

2
Stevan Cordas DO MPH

• Committee on Bioterrorism -Texas Department of
  Health (Division of Infectious Disease,
  Epidemiology and Surveillance) and Tarrant County
  Medical Society
• Clinical Assistant Professor of Medicine TCOM
  University of North Texas Health Science Center
• Consultant clinical toxicology and environmental
  medicine
• Certified allergy and immunology, internal
  medicine and occupational medicine

3
(No Transcript)
4
Organophosphates and Carbamyl Agents

• Diazinon (Spectracide)
• Malathion
• Parathion
• Chlorfenviphos
• Dimethoate
• Ronnel
• Nerve Gas Agents

• Pyridostigmine (Mestinon)
• Physostigmine (Antilirium)
• Neostigmine (Prostigmine)
• Cognex and others
• Sevin Dust, Carbaryl and many others

5
History of Nerve Gas

• First organophosphate 1854
• Tabun (GA) - Schroeder discovered 1936
• Sarin (GB) Schroeder discovered 1937
• Military production of tabun nazi 1942
• 30,000 tons of tabun produced 1942-45
• Soman (GD) discovered 1944

6
History of Nerve Gas

• GF discovered Schroeder 1944
• VX discovered Port Down, England 1955
• Russians captured tabun factories and start their
  own production-1946
• United states and England start their own
  production. Edgewood chemical and biologic
  center. 1950-1970

7
History of Nerve Gas

• President Nixon orders all chemical and biologic
  agents destroyed. 1969.
• Chemical stockpiles partially destroyed in the
  United States.
• Soviet union continued production 1946-91 -
  developed Novilchek agents - current production
  status uncertain.

8
History of Nerve Gas

• Iraq develops tabun and uses it against Iran
  1982-1985 . Iraq also used tabun against Kurdish
  dissidents.
• Iraq admits to placing sarin in scuds and
  artillery 1991- operation desert storm.
• Large amounts of chemical containers destroyed by
  U.S. forces 1991 98,900 low level exposures.
  Gulf war syndrome emerges.

9
History of Nerve Gas

• 1994 - First attack by Japanese cult using sarin
  gas 7 dead and 200 injured.
• 1995 Second attack same cult using sarin in
  Tokyo subways 12 dead and 6000 injured.
• 1998 Traces of VX found in Iraqi warheads.
• 2001-London police find sarin plans thwart
  attack.
• 2001- Insecticide bomb found on terrorist in
  Israel.

10
Sarin

• Also known as GB phosphonofluoridic acid,
  methyl, isopropyl ester Isoproposmethylphosphonyl
  fluoride
• Odorless and colorless
• Heavier than air hovers near the ground
• More lethal in higher temperature
• Degrades faster with rise in humidity
• 26 times more deadly than cyanide gas

11
These organophosphates are derivatives of
phosphonic acid
12
Basic Mechanism

• Nerve gases bind to an esterase (ChE) that breaks
  down acetylcholine after it is released from the
  nerve end plate.
• After a period of time this binding undergoes
  complex changes and cannot not be reversed this
  is called aging.
• This results in an excess acetylcholine (ACh)
  syndrome which affects the muscarinic and
  nicotinic receptors.

13
Aging Times of Various Nerve Gases in Humans

• Tabun (GA) gt 14 hours
• Sarin (GB) 5 hours
• Soman (GD) 2 to 6 minutes
• GF 40 hours
• VX 48 hours

14
The ACh Goes to Muscarinic and Nicotinic Receptor
Sites.
15
Signs and symptoms of Nerve Gas

• Miosis, dim vision, pain in eyes
• Severe rhinorrhea
• Bronchorrhea
• Nausea, Vomiting
• Diaphoresis
• Memory, fatigue, anxious, impaired judgment

• Increased airways resistance.
• Diarrhea and involuntary micturition.
• Local or generalized muscle fasciculations.
• Muscle fatigue then flaccid paralysis.
• Convulsions and Coma.

16
Clinical Picture when Exposed to Nerve Gas

• In mild cases, miosis, rhinorrhea, slight
  tightness in chest or bronchospasm,slight
  dyspnea, increased secretions, ocular pain and
  frontal headaches.
• In moderate cases. An exaggeration of the above
  symptoms with marked dyspnea, nausea and
  vomiting.

• In severe cases the same symptoms as for moderate
  but also confusion, unconsciousness, muscular
  fasciculations (generalized), involuntary
  micturition and defecation, apnea, flaccid
  paralysis, convulsions, arrhythmias.

17
RBC Cholinesterase Levels

• With minor adverse effects there is no
  correlation with RBC-ChE levels.
• With vomiting one can suspect that at least
  inhibition of 50 to 90 of the baseline ChE has
  occurred.
• Often used to verify organophosphate poisonings.
  Only otherwise decreased by pernicious anemia.

18
Case 1

• 27 year old male exposed to unknown substance
  that was lethal to others in the area.
• Subjective Anxiety, nausea, rhinorrhea, mild
  chest tightness.
• Objective Miosis, diaphoresis, elevated BP,
  regular heart rate, short onset time, seems
  stable. RBC cholinesterase 30 of normal.

19
Case 2

• 41 yr old male periods of apnea, convulsing,
  comatose, vomiting.
• Hypotensive, hypoxic, RBC cholinesterase 6 of
  normal.
• Increased airways resistance with copious
  secretions. Rhinorrhea, Diaphoresis, miosis.

20
Protect Yourself General Treatment Principles

• If an unknown agent is encountered go to MOPP 4
  or Level A.
• Decontaminate the patient, especially the hair.
  Use Clorox 110 dilution or water.
• ABC of resuscitation.
• Aggressively try to remove secretions.
• Diazepam 10mg if convulsing.

21
Specific Therapy for Nerve Gas

• Give atropine sulfate 2mg IV and 2 mg IM stat.
  Manage airways, breathing and circulation. Early
  intubation and ventilatory support with
  oxygenation. Repeat atropine 2mg IM every 5 or 10
  minutes and watch for return of copious
  secretions and increasing dyspnea.
• Follow atropine with Pralidoxime (2-PAM) 15 to 25
  mg/kg. The autoinjector contains 600 mg.
• Protopam in I g vials given over 15 minutes IV.

22
Effect of Atropine
23
2-PAM acts as a fulcrum to pry the nerve gas from
the acetylcholinesterase
24
Treatment (contd.)

• Little effect of 2 PAM treatment on Soman (GD)
  due to rapid aging.
• Pyridostigmine pretreatment is most helpful here
  and has some value with GA. Given orally 30mg
  every 8 hours.
• If the individual is alive 5 minutes after
  inhaling the vapor they probably can make it with
  your help.

25
Treatment (contd.)

• With liquid nerve gas (VX), very lethal, never
  used in combat.
• Decontamination is important as it ages slowly.
• A small amount on the skin can cause a delayed
  onset of symptoms. Miosis may not occur with very
  small amounts of VX.

26
Late effects of Nerve Gas Attacks

• Generally no serious adverse effects 6 months
  late.
• With convulsions and apnea, inability to learn
  new tasks, memory impairment and retrograde
  amnesia has occurred.
• No clear evidence of peripheral neuropathy or
  intermediate syndrome.

27
Storage and Dispersal

• Finite storage life
• Concept of Unitary verses Binary weapons
• Hazards of mixing and handling

28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
Summary

• Nerve Gas has already been used as a terror
  weapon.
• One drop can kill.
• If an individual survives the first 5 minutes,
  you probably can save their life.
• Protect Yourself.
• Learn how to recognize and treat this agent.

32
(No Transcript)
33
(No Transcript)