Two variants of occupational asthma separable by exhaled breath nitric oxide level.
نویسندگان
چکیده
UNLABELLED Exhaled nitric oxide (FE(NO)) has been used as a marker of asthmatic inflammation in non-occupational asthma, but some asthmatics have a normal FE(NO). In this study we investigated whether, normal FE(NO) variants have less reactivity in methacholine challenge and smaller peak expiratory flow (PEF) responses than high FE(NO) variants in a group of occupational asthmatics. METHODS We measured FE(NO) and PD(20) in methacholine challenge in 60 workers currently exposed to occupational agents, who were referred consecutively to a specialist occupational lung disease clinic and whose serial PEF records confirmed occupational asthma. Bronchial responsiveness (PD(20) in methacholine challenge) and the degree of PEF change to occupational exposures, (measured by calculating diurnal variation and the area between curves score of the serial PEF record in Oasys), were compared between those with normal and raised FE(NO). Potential confounding factors such as smoking, atopy and inhaled corticosteroid use were adjusted for. RESULTS There was a significant correlation between FE(NO) and bronchial hyper-responsiveness in methacholine challenge (p = 0.011), after controlling for confounders. Reactivity to methacholine was significantly lower in the normal FE(NO) group compared to the raised FE(NO) group (p = 0.035). The two FE(NO) variants did not differ significantly according to the causal agent, the magnitude of the response in PEF to the asthmagen at work, or diurnal variation. CONCLUSIONS Occupational asthma patients present as two different variants based on FE(NO). The group with normal FE(NO) have less reactivity in methacholine challenge, while the PEF changes in relation to work are similar.
منابع مشابه
Measurement of Exhaled Nitric Oxide and Exhaled Breath Condensate in the Diagnosis and Management of Asthma and Other Respiratory Disorders
Description of Procedure or Service Current techniques for diagnosing and monitoring asthma and predicting exacerbations are suboptimal. Two new strategies, evaluation of exhaled nitric oxide and exhaled breath condensate are proposed. These techniques are also potentially useful in the management of other conditions such as chronic obstructive pulmonary disease (COPD) and chronic cough. There ...
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عنوان ژورنال:
- Respiratory medicine
دوره 104 6 شماره
صفحات -
تاریخ انتشار 2010