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

Medical Management of Chemical Toxicity in Pediatricslead to burning of the eyes and throat, which is indicativeof mucous membrane irritation. More severelyexposed patients may complain of cough, choking, sorethroat, shortness of breath, chest tightness, difficultybreathing, and other respiratory-related issues. 92 Clinicalfindings may also include lacrimation, rhinorrhea,laryngeal edema, hoarseness, aphonia, stridor, expiratorywheezing, tracheitis, and cyanosis. 93,94 Tachypneamay develop as a direct result of pulmonary irritation,and tachycardia has been demonstrated in some casereports. 93,94 Many pediatric patients with prior historiesof reactive airway disease are at increased risk ofchlorine-induced bronchospasm. 92Pulse oximetry may indicate low oxygen saturationin patients exposed to pulmonary agents. 94 Whilearterial blood gases usually indicate hypoxemia, carbondioxide levels have been shown to be decreased,increased, or normal. 93,94 A hyperchloremic metabolicacidosis may be seen on blood chemistries due to systemicabsorption of hydrochloric acid. 94Pulmonary edema, the most significant morbidityof pulmonary agents, can be seen on chest roentograms.92 It may develop as early as 2 to 4 hours afterexposure; radiographic evidence typically appearslater. Pulmonary edema may produce Kerley B lineson chest X-rays. 92 These lines resemble the rungs of aladder running perpendicular to the lateral margin ofthe lungs, beginning at the costophrenic angle. Chestradiographs often show opacities of acute lung injury.Pneumomediastinum has also been reported in chlorinegas exposure. 94Pulmonary function tests are not helpful whenconfirming or treating pulmonary agent exposure. 94,95A study of school children exposed to a chlorine gasleak reported a predominantly obstructive pattern onpulmonary function tests. 95 This could be explainedby the children’s smaller airways or congestion andedema narrowing the central airways.Pediatric VulnerabilityChlorine is a pungent, green-yellow gas, twice asheavy as air, that settles near the ground. 92–94 This posesa particular problem for children, whose short statureplaces them closer to the ground. Children are mostcommonly exposed after inhaling chlorine vapors atswimming pools, 92 encountering household bleach(sodium hypochlorite) mixed with acidic cleaningagents, 94 and experiencing industrial accidents. 95 Phosgene,a dense gas that is also heavier than air, is a morelethal pulmonary agent than chlorine. While the smellof chlorine is associated with swimming pools, phosgeneodor is similar to that of freshly mown hay. 92Initially, both chlorine and phosgene cause coughingand intense mucosal membrane irritation, typicallyfollowed by a feeling of suffocation. 92–94 Morbidityfrom pulmonary agents is the direct result of pulmonaryedema, appearing between 2 and 4 hours afterchlorine exposure. Pulmonary edema can cause rapiddehydration or even shock in children because theyhave a smaller fluid reserve. 92TreatmentThe first line of treatment for children exposed topulmonary agents is decontamination. Decontaminationcan be as simple as removing the victim from thesource to fresh air, followed by removing contaminatedclothing. 92 Supportive care includes administering humidifiedair and supplemental oxygen, irrigation withwater, and delivering high-flow oxygen via positivepressure for pulmonary edema. 92,94 Further treatmentmay include surgical debridement and supportive carewith medications, such as albuterol for bronchospasm,corticosteroids for inflammation, and antibiotics forsecondary bacterial infections (Table 21-7). 92,94 Antidotesor specific postexposure treatments do not existfor this class of agents.CyanideCyanide is used in processing plastic, electroplatingmetals, tempering metals, and extracting goldand silver. It is found in fumigants, vehicle exhaust,tobacco smoke, certain fruit pits, and bitter almonds,and is used in photographic development. 96,97 Cyanideis liberated during the combustion or metabolismof natural and synthetic nitrogen-containing polymers.98 Cyanides can be lethal through inhalation oringestion, 99 and although cyanide exposure leads todeath in minutes, it can be effectively treated with antidotesif diagnosed early. 96,97 Pediatricians, medical firstresponders, and firefighters need to recognize victimsof cyanide poisoning in order to initiate immediateintervention. 96,97 Cyanide is one of the few chemicalsfor which an effective antidote exists.Mechanism of ToxicityThe cyanide ion kills mammalian organisms byshutting down oxidative phosphorylation in the mitochondriaand, therefore, the utilization of oxygen incells. 97,98 Cyanide has a propensity to affect certain organs(eg, brain, heart, and lungs) more than others. 96,97Significant exposure can lead to central respiratoryarrest and myocardial depression. 97 Cyanide also actsas a direct neurotoxin, disrupting cell membranes andcausing excitatory injury in the CNS. 96–98673