Medical Aspects of Chemical Warfare (2008) - The Black Vault

Nerve AgentsTABLE 5-4EFFECTS OF EXPOSURE TO NERVE AGENTVAPORTABLE 5-5EFFECTS OF DERMAL EXPOSURE TO LIQUIDNERVE AGENTSAmount of ExposureEffects*Level of ExposureEffectsSmall (local effects)Moderate (local effects)Largemuscular fasciculations; and miosis. One developedflaccid paralysis and apnea a minute or two later. Theother received immediate, vigorous treatment, and hiscondition did not progress.Dermal Exposure to LiquidMiosis, rhinorrhea, slight bronchoconstriction,secretions (slightdyspnea)Miosis, rhinorrhea, slight bronchoconstriction,secretions (moderateto marked dyspnea)Miosis, rhinorrhea, slight bronchoconstriction,secretions (moderateto marked dyspnea), lossof consciousness, convulsions(seizures), generalized fasciculations,flaccid paralysis, apnea,involuntary micturition/defecationpossible with seizures*Onset of effects occurs within seconds to several minutes afterexposure onset.The early effects of a drop of nerve agent on theskin and the time of onset of these effects depend onthe amount of nerve agent and several other factors,such as the site on the body, the temperature, and thehumidity. After a delay during which the individualis asymptomatic, localized sweating occurs at thesite of the droplet. Less commonly, there are localizedfasciculations of the underlying muscle (Table5-5). Unless the amount of the nerve agent is in thelethal range, the next effects (or perhaps the first effects,if the sweating and fasciculations do not occuror are not noticed) are gastrointestinal: nausea, vomiting,diarrhea, or a combination of these symptoms.The casualty may notice generalized sweating andcomplain of tiredness or otherwise feeling ill. Theremay be a period of many hours between exposureand the appearance of symptoms and signs. Thesesymptoms and signs may occur even if the casualtyhas been decontaminated. 48After large exposures, the time to onset of effectsmay be much shorter than for smaller exposures andMildEffects may be precipitantin onset afteran asymptomaticinterval of up to 18hoursModerateEffects may be precipitantin onset afteran asymptomaticinterval of up to 18hoursSevereEffects may be precipitantin onset aftera 2–30 minutes asymptomaticintervalIncreased sweating at the siteMuscular fasciculations at siteIncreased sweating at the siteMuscular fasciculations at siteNauseaDiarrheaGeneralized weaknessIncreased sweating at the siteMuscular fasciculations at siteNauseaDiarrheaGeneralized weaknessLoss of consciousnessConvulsions (seizures)Generalized fasciculationsFlaccid paralysisApneaGeneralized secretionsInvoluntary micturition/defecationpossible with seizuresdecreases as the amount of agent increases. For instance,two individuals were decontaminated withinminutes of exposure to a drop of nerve agent. Therewas a 15-minute to 20-minute asymptomatic intervalbefore the precipitant onset of effects: collapse, loss ofconsciousness, convulsive muscular jerks, fasciculations,respiratory embarrassment, and copious secretions.Within several minutes, the authors observedflaccid paralysis and apnea in both individuals.The major clinical differences between the inhalationaland dermal routes of exposure are the following:• Miosis and respiratory involvement are almostinvariant with inhalational exposure,but may be delayed or even absent in dermal169