Abstract

Background: A previous American College of Chest Physicians Consensus Statement on asthma in the workplace was published in 1995. The current Consensus Statement updates the previous one based on additional research that has been published since then, including findings relevant to preventive measures and work-exacerbated asthma (WEA).

Methods: A panel of experts, including allergists, pulmonologists, and occupational medicine physicians, was convened to develop this Consensus Document on the diagnosis and management of work-related asthma (WRA), based in part on a systematic review, that was performed by the University of Alberta/Capital Health Evidence-Based Practice and was supplemented by additional published studies to 2007.

Results: The Consensus Document defined WRA to include occupational asthma (ie, asthma induced by sensitizer or irritant work exposures) and WEA (ie, preexisting or concurrent asthma worsened by work factors). The Consensus Document focuses on the diagnosis and management of WRA (including diagnostic tests, and work and compensation issues), as well as preventive measures. WRA should be considered in all individuals with new-onset or worsening asthma, and a careful occupational history should be obtained. Diagnostic tests such as serial peak flow recordings, methacholine challenge tests, immunologic tests, and specific inhalation challenge tests (if available), can increase diagnostic certainty. Since the prognosis is better with early diagnosis and appropriate intervention, effective preventive measures for other workers with exposure should be addressed.

Conclusions: The substantial prevalence of WRA supports consideration of the diagnosis in all who present with new-onset or worsening asthma, followed by appropriate investigations and intervention including consideration of other exposed workers.

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Comments

These are consensus statements rather than evidence-based guidelines. The main consensus statements are as follows 1. In all individuals with new-onset or worsening asthma, take a history to screen for WRA (OA and WEA). Then confirm the diagnosis of asthma and investigate to determine whether the patient has WRA, performing these tests, whenever possible, prior to advising the patient to change jobs. 2. In all individuals with suspected WRA, obtain a history of job duties, exposures, industry, use of protective devices/equipment, and the presence of respiratory disease in coworkers, and consult material safety data sheets (MSDSs), which list many recognized hazardous agents. Document the onset and timing of symptoms, medication use, and lung function, and their temporal relationship to periods at and away from work. 3. In individuals who have asthma not caused by work but that subsequently worsens while working, consider the diagnosis of WEA, which is usually based on changes in symptoms, medication use, and/or lung function temporally related to work. 4. In individuals with suspected sensitizerinduced OA, in addition to carefully documenting the occupational history, perform additional objective tests when feasible (eg, serial peak flow recordings, serial methacholine challenges, immunologic assessments, induced sputum testing, and SICs) to improve the diagnostic probability. 5. In individuals with suspected WRA who are currently working at the job in question, record serial measurements of peak flow as part of the diagnostic evaluation and ask the patient to record these optimally a minimum of four times daily, for at least 2 weeks at work and 2 weeks off work. 6. In individuals with suspected sensitizerinduced OA, working at the job in question, perform a methacholine challenge test or obtain comparable measurements of nonspecific airway responsiveness during a working period, and repeat it during a period (optimally, at least 2 weeks) away from the work exposure to identify work-related changes. 7. In individuals with suspected sensitizerinduced OA, perform immunologic tests (skin prick testing or in vitro specific IgE assays) to identify sensitization to specific work allergens when these tests are technically reliable and available. 8. In individuals with suspected sensitizerinduced OA, conducting an SIC (where available) is suggested when the diagnosis or causative agent remains equivocal; however, this testing should only be performed in specialized facilities, with medical supervision throughout the testing. 9. For all individuals with WRA, attempt better control of exposures. Remove patients with sensitizer-induced OA from further exposure to the causative agent in addition to providing other asthma management. 10. In individuals with irritant-induced asthma or WEA, the panel advises optimizing asthma treatment and reducing the exposure to relevant workplace triggers. If not successful, change to a workplace with fewer triggers is suggested in order to control asthma. 11. For workers who are potentially exposed to sensitizers or uncontrolled levels of irritants, the panel advises primary prevention through the control of exposures (eg, elimination, substitution, process modification, respirator use, and engineering control). 12. An individual diagnosis of OA represents a potential sentinel health event: 1) Evaluate the workplace to identify and prevent other cases of OA in the same setting; and 2) For work environments with potential exposure to sensitizers, the Panel advises secondary preventive measures including medical surveillance using tools such as questionnaires, spirometry, and, where available, immunologic tests.

10/18/2008

They have defined work exacerbated asthma as asthma triggered by various work-related factors (eg, aeroallergens, irritants, or exercise) in workers who are known to have preexisting or concurrent asthma (ie, asthma that is occurring at the same time but is not caused by workplace exposures). Some differentiate between WEA and work-aggravated asthma, based on whether the worker returns to a prior asthma baseline (WEA) or not (work-aggravated asthma); but, this distinction is not widely accepted, and this Consensus Document will use the term WEA

12/7/2009