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Medline ® Abstracts for References 48,61

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

Long-term outcomes of acute irritant-induced asthma.
Malo JL, L'archevêque J, Castellanos L, Lavoie K, Ghezzo H, Maghni K
Am J Respir Crit Care Med. 2009;179(10):923.
RATIONALE: The long-term outcomes of acute irritant-induced asthma (IIA) are mostly unknown.
OBJECTIVES: To study the long-term outcomes of IIA.
METHODS: We reassessed 35 subjects who experienced IIA at a mean interval of 13.6 +/- 5.2 years.
MEASUREMENTS AND MAIN RESULTS: The causal agent was chlorine in 20 cases (57%). At diagnosis, the mean +/- SD FEV(1) was 74.5 +/- 19.5% predicted, and all subjects showed bronchial hyperresponsiveness. At reassessment, all subjects reported respiratory symptoms, and 24 (68%) were on inhaled steroids. There were no significant improvements in FEV(1) and FEV(1)/FVC values. Twenty-three subjects had a methacholine test, and only six subjects had normal levels of responsiveness. Of the remaining 12 subjects, six had improvement in FEV(1) after bronchodilator>or=10%. In samples of induced sputum obtained from 27 subjects, six had eosinophils>or=2%. Levels of inflammatory and remodeling mediators were higher than in control subjects but wereno different from subjects with occupational asthma due to sensitization. Quality of life score was 4.4 +/- 1.5 on a 0 (worst) to 7 (best) scale. Twelve subjects had an abnormal depression score.
CONCLUSIONS: This study provides the first evidence of significant long-term impact of acute IIA on various outcomes.
Axe de Recherche en SantéRespiratoire, Hôpital du Sacré-Coeur de Montréal, Quebec. malojl@meddir.umontreal.ca
Workplace-related chronic cough on a mushroom farm.
Tanaka H, Saikai T, Sugawara H, Takeya I, Tsunematsu K, Matsuura A, Abe S
Chest. 2002;122(3):1080.
BACKGROUND: Mushroom spores have frequently been associated with respiratory allergy. The aims of this study were to elucidate the incidence and causes of chronic cough in a mushroom farm.
METHODS: Participants were 69 mushroom workers who produce Hypsizigus marmoreus (Bunashimeji) and 35 control subjects. We excluded six workers because they had had asthma or allergic rhinitis before working. Participants completed a cross-sectional health survey 2 years after starting work at the mushroom farm.
RESULTS: The mean airborne endotoxin levels in the harvesting and packing rooms were approximately 60-fold higher than those in the offices. Of 63 workers, 42 workers (67%) reported chronic cough after working on this farm, 19 workers had no cough, while 2 workers had hypersensitivity pneumonitis develop to the spore, which has been previously reported by us. Of the 42 workers with cough, 6 workers had organic dust toxic syndrome (ODTS), 18 workers had postnasal drip syndrome, 15 workers had cough variant asthma, and 3 workers had eosinophilic bronchitis. Seventy-one percent of the workers noticed the cough in the first 3 months, and the mean latent period in ODTS workers was the shortest. The cough had a trend to improve or disappear after weekend holidays. Bronchial hyperresponsiveness but not FEV(1)/FVC% in the 42 workers with cough was significantly (p<0.001) increased as compared with the control subjects.
CONCLUSIONS: Working on a mushroom farm carries a significant risk for chronic cough from inhalation of mushroom spores, and we suggest that elevated airborne endotoxin on this farm is the cause.
Third Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan. tanakah@sapmed.ac.jp