Veterans at Risk The Health Effects of Mustard Gas and Lewisite (1993) / Chapter Skim
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7 Nonmalignant Respiratory Effects of Mustard Agents and Lewisite
7 Nonmalignant Respiratory Effects of Mustard Agents and Lewisite
Pages 112-130
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From page 112... ...
If a risk of chronic effects is judged to exist among these human subjects, a secondary question arises as to whether an acute response is a necessary precursor to the development of long-term respiratory effects. There are few directly relevant studies available for answering these questions and, as discussed in Chapter 3, the long-term health status of the subjects has not been followed.
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From page 113... ...
attempt to understand the relationship between the acute and chronic responses to these agents, other respiratory hazards known to cause both acute and chronic effects are also reviewed. PHYSIOLOGY AND ANATOMY The basic anatomy of the respiratory tract is illustrated in Figure 7-1.
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From page 114... ...
A: simple squamous; B: simple cuboidal; C: simple columnar; D: ciliated columnar; E: pseudostratified ciliated columnar with goblet cells; and F: stratified squamous. SOURCE: Adapted from Stedman's Medical Dictionary, 1976, with permission from Williams & Wilkins.
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From page 115... ...
ACUTE EFFECTS AND BIOLOGICAL MECHANISMS The inhalation of sulfur mustard or Lewisite causes acute damage to the respiratory tract, but the symptoms of exposure are not immediate and develop over a period of several days. Pulmonary injury is in fact the principal cause of mortality in the first few days to weeks after exposure to sulfur mustard (Hosseini et al., 1989; Papirmeister et al., 1991; Willems, 1989~.
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From page 117... ...
Nevertheless, the descriptions of the more severe lesions of the respiratory tract of animals exposed to sulfur mustard vapor and those in humans appear to be quite similar in type and location (Papirmeister et al., 1991~. Thus, further studies in animals conducted to follow the repair of the acute respiratory tract lesions from nonlethal, inhaled sulfur mustard vapor would be of value in determining the persistence and course of such lesions in people.
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From page 118... ...
Thus, it is conceivable that some sulfur mustard exposure of respiratory tract tissue with subsequent biological effects could occur following systemic absorption from skin exposure.
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From page 119... ...
Occupational Exposure There is some relatively recent epidemiologic literature on occupational exposure to mustard agents in British and Japanese munitions factories. Several studies suggest that workers who were chronically exposed to mustard agents developed chronic nonmalignant respiratory effects (Easton et al., 1988; Manning et al., 1981; Nishimoto et al., 1970~.
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From page 120... ...
The former poison gas workers showed a more bronchitic type of airway obstructive pattern than did the ordinary patients with chronic obstructive pulmonary disease (COPD) ; however, they did not have less anatomical evidence of emphysema.
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From page 121... ...
These investigators concluded that 27 of the 89 men who were examined nine to ten years after gassing had evidence of anatomic or symptomatic disease attributable to their exposure to sulfur mustard. The residual effects on the respiratory tract they noted were chronic bronchitis, emphysema, and bronchial asthma.
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From page 122... ...
described delayed effects, present two years after the exposure, which includecI chronic bronchitis and recurrent pneumonia. In summary, the literature on the longer-term respiratory effects of acute combat exposures suggests the presence of significant chronic lung disease of both an obstructive and a restrictive nature.
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From page 123... ...
RELATIONSHIP BETWEEN ACUTE AND CHRONIC EFFECTS CAUSED BY EXPOSURES TO OTHER RESPIRATORY HAZARDS There is clear evidence from descriptions of severe overexposure to sulfur mustard that exposure can cause both acute and chronic respiratory disease. However, there is little information available on the effects of lower levels of acute exposure, and apparently no information on the relatively brief exposures to levels that typify the experience in the chamber and some field studies.
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From page 124... ...
Finally, there is evidence that short-term exposures to isocyanates can cause acute responses that are irreversible and progressive, but there is no evidence as to whether such short-term exposures without acute response result in irreversible respiratory effects. Beryllium exposures have also been associated with both acute and chronic pulmonary disease, both of which have been shown to be disabling (AMA Archives of Industrial Health, 1959~.
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From page 125... ...
Based on this review, a set of answers has been suggested for the following key questions regarding sulfur mustard and Lewisite exposure and chronic nonmalignant pulmonary disease. However, it should be kept in mind that there is a shilling absence of knowledge about the early stages of environmentally related pulmonary diseases and almost no knowledge on the natural (longitudinal)
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From page 126... ...
This may be the most important question to ask and, unfortunately, the one for which no direct evidence could be found. The indirect evidence, however, would suggest the need to invoke an unusual disease model, one in which changes in individual risk factors could be excluded from the list of possible mechanisms, so that the absence of an acute reaction would eliminate the possibility of any chronic effects related to a short-term or acute exposure.
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From page 127... ...
used in the WWII experiments and chronic nonreversible lung diseases. Indirect evidence, based on a review of the relationships between acute and chronic effects caused by other substances, suggests that the likelihood of long-term respiratory effects may not necessarily be linked to the presence of an acute respiratory response.
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From page 128... ...
1988. Cancers of the respiratory tract in mustard gas workers.
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From page 129... ...
1978. Multiple Bowen's disease observed in former workers of a poison gas factory in Japan with special reference to mustard gas exposure.
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From page 130... ...
1919. Anatomical changes in the respiratory tract initiated by irritating gases.
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