management of suspected FGA exposures differs from the approach used for traditional nerve agents All individuals suspected of having been exposed need to be identified, decontaminated, and observed, with serial determinations of RBC cholinesterase or plasma cholinesterase as well as heart rate and temperature monitoring Meanwhile, epidemiologic clues may lead to the identification of additional possibly exposed individuals A-series agents are difficult to treat once victims have gone into cholinergic crisis; aggressive treatment with atropine and an oxime is needed along with scopolamine (initially mg IV in adults; the dose may be scaled down for children) During the latent period, victims need to be decontaminated thoroughly as soon as possible, although decontamination may be effective even an hour or two after exposure Heart rate, core temperature, and cholinesterase levels in the blood or plasma (or both) should be monitored Pyridostigmine bromide (PB) 30 mg orally every hours in adults (lower doses scaled to body weight are appropriate for children) should be considered; this is normally given as a pretreatment for nerve-agent exposure and is not given after the onset of cholinergic crisis PB is a carbamate anticholinesterase used in anesthesia and in the treatment of conditions such as myasthenia gravis At the time of the 1990 Gulf War, the U.S FDA approved it as a pretreatment to be given before exposure in situations in which the risk of exposure to the traditional nerve agent soman (GD) was high (PB is a pretreatment , or pre-exposure antidotal enhancement, not prophylaxis ; it helps antidotes to work better, but the antidotes still have to be given.) Subsequently, the FDA extended that approval for conditions in which exposure to any nerve agent was likely PB pretreatment is not normally a consideration outside military scenarios, but because of the long latent periods with FGAs, administration of PB during the latent period, when the outside of the body has technically been exposed but the target organs (the CNS, skeletal muscles, smooth muscles, and exocrine glands) have not yet been exposed, could theoretically be of use If a provider–patient relationship exists, PB might be considered when given under informed consent PB will predictably depress cholinesterase levels, but the drop is only about 30% from the preadministration values; if cholinesterase levels drop precipitously during the latent period, or if the heart rate or core temperature decreases by more than 25% from baseline, the patient should be treated for full-blown cholinergic crisis TABLE 132.4 PRIMARY THREAT CHEMICAL AGENTS OF TERRORISM TABLE 132.5 AUTOINJECTOR ADMINISTRATION OF NERVE-AGENT ANTIDOTES FOR INITIAL THERAPY OF SEVERELY AFFECTED MASS CASUALTIES OR IN PREHOSPITAL SETTING Atropine Approximate age Approximate weight (kg) Autoinjector size (mg) a 50 Diazepam (10 mg each, for seizures, or severe exposure) Approximate age (yrs) Number of autoinjectors 5–Adolescent Adolescent and older a Administer one autoinjector of each size indicated autoinjectors (e.g., mg of atropine, 600-mg pralidoxime, combination of 2.1-mg atropine and 600-mg pralidoxime or 10-mg diazepam), while not approved for pediatric use, might be considered as initial treatment in dire (especially prehospital) circumstances, for children with severe, life-threatening nerve-agent toxicity who lack intravenous access, and for whom more precise, mg/kg IM dosing (as per Table 132.4 ) would be logistically impossible Suggested pralidoxime dosing guidelines are offered: Note potential excess of initial dose for age/weight, although within general guidelines for recommended total over first 60–90 of therapy of severe exposures c The combination autoinjectors may also be used for children in these age and size categories, as noted, to replace both atropine and pralidoxime for initial therapy in severe cases Such use will result in moderate excess dosage of both antidotes, but again, generally within the guidelines for recommended total over the first 60–90 of therapy for severe exposures b Adult-intended Adapted from Henretig FM, Cieslak TJ, Eitzen EM Jr Biological and chemical terrorism J Pediatr 2002;141:311–326 Copyright © 2002 Elsevier With permission FIGURE 132.7 Autoinjector-packaged pralidoxime can be injected into an empty vial for subsequent reuse in small pediatric patients (Reprinted from Henretig FM, Mechem C, Jew R Potential use of autoinjector-packaged antidotes for treatment of pediatric nerve agent toxicity Ann Emerg Med 2002;40:405–408 Copyright © 2002 American College of Emergency Physicians With permission.) Specific Pediatric Considerations The thinner skin of children might make them more susceptible to dermal absorption of chemical toxins in comparison to adults ( Table 132.2 ) Likewise, the immature blood–brain barrier in infants might increase the relative risk of CNS toxicity Children have smaller airway diameters, anatomic subglottic narrowing, and higher respiratory rates as well as exhibit limited endurance of the accessory muscles of breathing; these characteristics could predispose to earlier and more severe respiratory effects from nerve agents In addition, children have a greater susceptibility to seizures Although OP-pesticide poisoning in children may certainly manifest by dramatic muscarinic findings, including respiratory compromise (see Chapter 102 Toxicologic Emergencies ), one case series of anticholinesterase pesticide poisoning in children found that depressed sensorium and muscle weakness and flaccidity were more prominent than muscarinic findings Nevertheless, more than half of these patients did demonstrate miosis (80%), tearing and excess salivation (60%), and GI findings (52%) Other studies have shown an absence of ... for subsequent reuse in small pediatric patients (Reprinted from Henretig FM, Mechem C, Jew R Potential use of autoinjector-packaged antidotes for treatment of pediatric nerve agent toxicity... toxicity Ann Emerg Med 2002;40:405–408 Copyright © 2002 American College of Emergency Physicians With permission.) Specific Pediatric Considerations The thinner skin of children might make them more... combination of 2.1-mg atropine and 600-mg pralidoxime or 10-mg diazepam), while not approved for pediatric use, might be considered as initial treatment in dire (especially prehospital) circumstances,