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

Toxins: Established and Emergent Threatsdyspnea develops, monitor for hypoxia, respiratorytract irritation, bronchitis, or pneumonitis. Symptomatictreatment should consist of 100% humidifiedsupplemental oxygen. The patient should be monitoredfor systemic signs of toxicity as well as the needfor endotracheal intubation and assisted ventilation.Bronchospasm can be reversed using beta-2 adrenergicagonists. Ipratropium and systemic corticosteroidsfor bronchospasm should be started with continuedmonitoring of peak expiratory flow rate, hypoxia,and respiratory failure, or nebulized albuterol oripratropium added to the nebulized albuterol. Systemiccorticosteroids, such as prednisone, can reducethe inflammation associated with bronchospasm andasthma. For ocular or dermal exposure, eyes and skinshould be flushed with copious amounts of water.StabilityPbTx derivatives exhibit remarkably stable properties.In aqueous or organic solvent solutions, PbTxremains potent for months; culture media that containedgrowing Karenia brevis maintained its abilityto intoxicate for similar periods. PbTxs are reportedlysensitive to air, 174 so commercial source PbTx is shippedin nitrogen-blanketed or evacuated containers. LyophilizedPbTx is stable for months without special storageconditions, and certain derivatives, such as PbTx-2and PbTx-3, have been reported to be heat stable atextreme temperatures (300°C). The relative stabilityof PbTx and the ease with which lyophilized PbTxcan be reconstituted make PbTx an attractive toxin tobe weaponized.ProtectionNo cases of paralysis or death from NSP have beenreported. 157 Symptoms of PbTx intoxication as detailedabove generally begin within 15 minutes of exposure,but may occur as late as 18 hours post-exposure, withsymptoms potentially persisting for several days.Treatment for NSP or PbTx poisoning consists of supportivecare; there is no antidote or antitoxin for PbTxexposure.For individuals sensitive to PbTx inhalation exposure,a respiratory barrier or particle filter mask anddeparture from the area of exposure to an air conditionedor filtered environment should provide relieffrom inhalation exposure symptoms. The bronchoconstricitveairway response to inhaled PbTx in a sheepasthma model can be relieved by the use of histamineH1 antagonist diphenhydrimine, atropine, and thenatural polyether brevenal. 165,175 This may direct furtherresearch and provide treatment options for bothasthmatics and other susceptible persons exposed toaerosolized PbTxs. PbTxs can be easily oxidized bytreatment with potassium permanganate (KMnO 4).This reaction is irreversible, proceeds quickly, leavesa nontoxic compound, 176 and is a potential means ofdetoxification.SurveillanceSignificant information is available on morbidityand mortality in aquatic animal populations exposedto red tide toxins, including domoic acid, PbTxs,STXs, and ciguatoxins. Much of what is known aboutgross and histopathologic analyses, diagnostics, andtherapeutic countermeasures for these toxins has beengleaned from environmental population exposurestudies. 177 Historically, marine mammals (pinnipeds,cetaceans, and sirenians), aquatic birds, sea turtles, fish,and invertebrates are environmental sentinel species.All are susceptible to toxin exposure via ingestion andimmersion; however, marine mammals and sea turtlesare particularly susceptible to respiratory exposure atthe air-water interface, where aerosolization and concentrationoccurs. In addition, marine mammals havepoor tracheobronchial mucociliary clearance comparedto terrestrial mammals.Although human and environmental impacts oncoastal seawater quality and temperature can resultin significant algal blooms, it is unlikely that a terroristattack would attempt to directly impact red tides.However, an intentional chemical spill or factory attackcould lead to subsequent algal blooms. Communicationwith marine mammal and sea turtle strandingnetworks, as well as other environmental agencies (eg,the Environmental Protection Agency, National Oceanicand Atmospheric Administration, etc), is criticalin the early identification of adverse health effects onsentinel species.A tampered freshwater source, such as a reservoir,would also have effects on fish, aquatic birds, andmammals in that system. A real-time, automated, biomonitoring,portable ventilatory unit developed by theUS Army Center for Environmental Health Researchmeasures gill rate, depth, purge (cough rate), and totalbody movement determined by amplified, filtered,electrical signals generated by opercular (gill) movementsin bluegill (Lepomis macrochirus) and recordedby carbon block electrodes. 178 Biomonitor studies havealready been conducted to determine the effects ofPbTx-2 and toxic Pfiesteria piscicida cultures on bluegill.179 Applications for this biomonitoring system haveincluded watershed protection, wastewater treatmentplant effluent, and source water for drinking waterprotection.631