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

Medical Aspects of Chemical WarfareThe Iranian data suggest that surviving victims ofmustard exposure during the Iran-Iraq War are exhibitingcarcinoma of the nasopharynx, bronchogeniccarcinoma, and adenocarcinoma of the stomach, aswell as acute myeloblastic and lymphoblastic leukemia.27 Definitive studies of the nature and types ofcancers seen in this patient population have yet to bepublished.Chronic Pulmonary DiseaseInhalation of mustard vapor primarily affects thelaryngeal and tracheobronchial mucosa. 6 Evidencesuggests that mustard inhalation causes sustainedrespiratory difficulties even after the acute lesionshave healed. Clinical follow-ups on 200 Iranian soldierswho were severely injured by mustard duringthe Iran–Iraq War indicate that about one third hadexperienced persistent respiratory effects 2 years afterinitial exposure. Reported problems included chronicbronchitis, asthma, rhinopharyngitis, tracheobronchitis,laryngitis, recurrent pneumonia, bronchiectasis,and in some cases, severe, unrelenting tracheobronchialstenosis. 22,40–43Of the British soldiers exposed to mustard in WorldWar I, 12% were awarded disability compensation forrespiratory disorders that were believed to be frommustard exposures during combat. 44 Bronchitis wasthe major complaint; emphysema and asthma werealso reported. However, epidemiological studies of therelationship between agent exposure and subsequentrespiratory disability were severely limited for severalreasons. Often, individuals had experienced multiplecombined exposures to mustard and other chemicalagents. Also, influenza and other respiratory ailmentsfrequently made diagnosis of the mustard vapor injurydifficult. 6 Finally, no epidemiological controls forsmoking or for postexposure environmental and occupationalhistories were included in the studies. 45Wada et al 34 suggest a causal relationship betweenmustard exposure and subsequent bronchitis, tuberculosis,and pneumonia in factory workers involved inthe production of mustard. Again, Morgenstern et al 14and Buscher 15 emphasize that chronic low-dose exposureover prolonged periods (presumably months toyears) leads to lingering bronchitis, bronchial asthma,hoarseness, aphonia, and hypersensitivity to smoke,dust, and fumes. Affected individuals typically showpersistent disability, with increased susceptibility torespiratory tract infections and evidence of bronchitisand bronchiectasis. 6Little contemporary information regarding thepathogenesis of the respiratory lesions is available, andfew data from people or animals exposed to nonlethalconcentrations of mustard vapor exist. Even fewerstudies investigate the histopathology of the recoveryprocess in animals exposed to mustard. 19 However,two studies 9,46 conducted during World War I suggestthat low-level exposure or survivable exposures indogs and rabbits may produce scar tissue followingsmall ulcerations in the trachea and larynx, causingcontractions of these areas. The more severe respiratorytract lesions described in animals exposed to mustardvapor appear to be similar in type and location to thosedescribed in humans. 6The Iranian database shows that in the 3-yearpostexposure time frame the most severely affectedpatients demonstrated restrictive pulmonary diseasepatterns. By 16 years postexposure, these patternshad become obstructive in nature. 27 Sixteen to twentyyears after exposure, the main respiratory complicationswere chronic obstructive pulmonary disease,bronchiectasis, asthma, large airway narrowing, andpulmonary fibrosis. 27Chronic Eye DiseaseIndividuals who sustain acute ocular injury fromhigh-dose mustard exposure may experience difficultieseven after the initial effects of the injury havesubsided. 47–50 Recurrent or persistent corneal ulcerationcan occur after latent periods of 10 to 25 years.This delayed keratopathy 49,51 may be accompanied bychronic conjunctivitis and corneal clouding. Anecdotalaccounts suggest that low-dose exposure also causesincreased sensitivity to later exposures to mustard, 52although the existence of increased sensitivity is difficultto substantiate with available scientific evidence. 6About 10% of those with eye injury in World War I hadseverely affected eyes, with both the cornea and theconjunctiva being involved. Members of this groupdeveloped the “delayed keratitis” noted above 8 to25 years later. 48The 1993 Institute of Medicine study 19 of the effectsof mustard and lewisite exposure on the healthof veterans concluded that acute, severe injury of theeye from mustard might result in recurrent cornealulcerative disease for the remainder of the patient’slife, with a maximum incidence occurring 15 to 20years after the injury. Based on extensive data, thestudy concluded that a causal relationship betweensevere exposure to mustard and the development ofdelayed recurrent keratitis exists. 47 The study alsofound a causal relationship between exposure to mustardand the development of prolonged, intractableconjunctivitis.314