Medline ® Abstracts for References 17,18

of 'Reactive airways dysfunction syndrome and irritant-induced asthma'

17
TI
Workplace irritant exposures: do they produce true occupational asthma?
AU
Tarlo SM
SO
Ann Allergy Asthma Immunol. 2003;90(5 Suppl 2):19.
 
OBJECTIVE: To describe the features of irritant-induced asthma and discuss the diagnosis in relation to differing workplace irritant exposures and symptomatic responses.
DATA SOURCES: A review of MEDLINE articles on this topic from January 1, 1985, through December 31, 2001 was performed.
STUDY SELECTION: The author selected relevant articles for inclusion in the review.
RESULTS: Many reports indicate that unintentional high-level respiratory irritant exposures can induce the new onset of asthma. Cases that meet strict criteria for a syndrome of irritant-induced asthma, termed reactive airways dysfunction syndrome, can be diagnosed with relative certainty. Several reports of irritant-induced asthma, especially prevalence studies, have relied on historical data or have otherwise modified the reactive airways dysfunction syndrome criteria for diagnosis (eg, expanding the definition to include the symptom onset several days after exposure). Such modifications, or inclusion of cases with incomplete documentation, likely increase diagnostic sensitivity but may reduce the certainty of diagnosis for individual cases. Expanding exposure criteria to moderate or long-term low-level irritant exposures causes difficulty in excluding transient irritant exacerbation of underlying asthma or coincidental onset of asthma during working life. Although recent population studies suggest a greater relative risk of asthma in occupations with expected low-to-moderate respiratory irritant exposures, currently no objective laboratory tests exist to exclude coincidental asthma in such patients.
CONCLUSIONS: Irritant-induced asthma can be produced by high-level unintentional respiratory irritant exposures at work or outside the workplace. Lower levels of exposure to respiratory irritants at work are more common, and additional studies are needed to determine the airway effects of such exposures.
AD
Department of Medicine, University of Toronto, Toronto Western Hospital, Gage Occupational and Environmental Health Unit, Toronto, Ontario, Canada. susan.tarlo@utoronto.ca
PMID
18
TI
Cross-sectional assessment of workers with repeated exposure to chlorine over a three year period.
AU
Gautrin D, Leroyer C, L'Archevêque J, Dufour JG, Girard D, Malo JL
SO
Eur Respir J. 1995;8(12):2046.
 
Airflow obstruction has been described in workers who experienced symptoms after acute exposure to chlorine. Persistent bronchial hyperresponsiveness has also been assessed, but mainly in case studies. In this cross-sectional study, we have assessed the relationship between inhalational accidents ("puffs") involving chlorine and persistent symptoms as well as hyperresponsiveness in 239 out of 255 at-risk workers (94%). No relationship was found between persistent symptoms and the exposure variables studied. Forced vital capacity (FVC) was higher in subjects who had had no symptoms after a "puff", compared with those who had experienced mild symptoms. Forced expiratory volume in one second (FEV1) and FVC were significantly lower in subjects who experienced more than 10 puffs with mild symptoms than in subjects who reported no symptomatic puff. The presence of bronchial hyperresponsiveness was not related to exposure, but the methacholine dose-response slope showed a tendency to increased bronchial responsiveness with increased exposure. A significant difference was shown in subjects who experienced more than 10 puffs with mild symptoms. In this group of workers, repeated exposure to chlorine with acute respiratory symptoms was associated with a slight but significant reduction in expiratory flow rates, together with an increase in bronchial responsiveness, without long-term symptoms.
AD
Dept of Chest Medicine, Hôpital du Sacré-Coeur, Montreal, Canada.
PMID