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

Medical Aspects of Chemical Warfareexposure.• The speed of onset and progression of symptomswill be far faster in inhalational exposure.• Decontamination of dermal exposure may notoccur before agent has penetrated the skin,and consequently patients who are treated fornerve agent symptoms after dermal exposuremay subsequently worsen as agent becomesavailable systemically. This is not likely withinhalational exposure.Exposure to nerve agent liquid through a woundwill likely produce effects intermediately.EFFECTS ON ORGANS AND ORGAN SYSTEMSMost of the information on the effects of nerve agentson organ systems in humans is derived from studiesdone in the post–World War II period, from reports ofpeople exposed to pesticides, or from clinical evaluationsof accidental exposures of people who workedin nerve agent research laboratories, manufacturingfacilities, or storage areas or depots (Table 5-6). Someorgan systems have been studied more intensively thanothers. For example, there is a plethora of data fromanimal studies and studies in isolated neuromuscularpreparations for the musculoskeletal system, but studyresults are difficult to apply to a human clinical situation.The two terrorist attacks using sarin in Japan in1994 and 1995 have provided a fund of new humanclinical data, but this data is all uncontrolled. The Japaneseterrorist and Iranian battlefield clinical experienceis summarized in a later section of this chapter.The EyeNerve agents in the eye may cause miosis, conjunctivalinjection, pain in or around the eye, and dim orblurred vision (or both). Reflex nausea and vomitingmay accompany eye exposure. These effects are usuallylocal, occurring when the eye is in direct contact withnerve agent vapor, aerosol, or liquid, but exposure byother routes (such as on the skin) can also affect theeyes. Because eyes often react late in the course ofintoxication in the latter case (exposure on the skin),they cannot be relied on as an early indication of exposure.Systemic (such as skin or perioral) exposure to anerve agent might be large enough to produce moderatesymptoms (nausea, vomiting) without miosis.In studies 43,44,47 in which VX was placed on the skin,administered intravenously, or given orally, a significantnumber of subjects experienced nausea, vomiting,sweating, or weakness, but none had miosis. In47 patients with parathion poisoning, all of the 14severe cases had miosis, whereas 6 of 11 patients withmoderate poisoning and only 5 of 22 patients withmild effects had miosis. 54 On the other hand, a vaporor aerosol exposure might cause miosis without othersigns or symptoms and an exposure in one eye willcause miosis in that eye (a local effect because of amask leak in one eyepiece or similar causes) withoutTABLE 5-6EFFECTS OF NERVE AGENTS IN HUMANSOrgan or SystemEyeNoseMouthPulmonary tractGastrointestinaltractSkin and sweatglandsMuscularCardiovascularCentral nervoussystemEffectMiosis (unilateral or bilateral),conjunctival injection; pain in oraround the eye; complaints of dimor blurred visionRhinorrheaSalivationBronchoconstriction and secretions,cough; complaints of tight chest,shortness of breath; wheezing, rales,and/or rhonchi on examIncrease in secretions and motility;nausea, vomiting, diarrhea; complaintsof abdominal cramps, painSweatingFasciculations (“rippling”), local orgeneralized; twitching of musclegroups, flaccid paralysis; complaintsof twitching, weaknessDecrease or increase in heart rate;usually increase in blood pressureAcute effects of severe exposure: lossof consciousness, convulsion (orseizures after muscular paralysis),depression of respiratory center toproduce apneaAcute effects of mild or moderateexposure or lingering effects (daysto weeks) of any exposure: forgetfulness,irritability, impaired judgment,decreased comprehension, a feelingof tenseness or uneasiness, depression,insomnia, nightmares, difficultywith expression170