Diagnosis and management of work-related asthma: American College Of Chest Physicians Consensus Statement
ABSTRACT 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).
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.
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.
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.
- SourceAvailable from: John D Brannan
[Show abstract] [Hide abstract]
- "Allergen inhalation is primarily used in research as it can cause a late airway response approximately 6–8 h following the early bronchoconstriction (O'Byrne et al., 2009a). However, the clinical use of specific allergen inhalation tests is limited to specialized tertiary care centers, for example to evaluate work-related asthma (Tarlo et al., 2008). "
ABSTRACT: Airway hyperresponsiveness (AHR) and airway inflammation are key pathophysiological features of asthma. Bronchial provocation tests (BPTs) are objective tests for AHR that are clinically useful to aid in the diagnosis of asthma in both adults and children. BPTs can be either "direct" or "indirect," referring to the mechanism by which a stimulus mediates bronchoconstriction. Direct BPTs refer to the administration of pharmacological agonist (e.g., methacholine or histamine) that act on specific receptors on the airway smooth muscle. Airway inflammation and/or airway remodeling may be key determinants of the response to direct stimuli. Indirect BPTs are those in which the stimulus causes the release of mediators of bronchoconstriction from inflammatory cells (e.g., exercise, allergen, mannitol). Airway sensitivity to indirect stimuli is dependent upon the presence of inflammation (e.g., mast cells, eosinophils), which responds to treatment with inhaled corticosteroids (ICS). Thus, there is a stronger relationship between indices of steroid-sensitive inflammation (e.g., sputum eosinophils, fraction of exhaled nitric oxide) and airway sensitivity to indirect compared to direct stimuli. Regular treatment with ICS does not result in the complete inhibition of responsiveness to direct stimuli. AHR to indirect stimuli identifies individuals that are highly likely to have a clinical improvement with ICS therapy in association with an inhibition of airway sensitivity following weeks to months of treatment with ICS. To comprehend the clinical utility of direct or indirect stimuli in either diagnosis of asthma or monitoring of therapeutic intervention requires an understanding of the underlying pathophysiology of AHR and mechanisms of action of both stimuli.Frontiers in Physiology 12/2012; 3:460. DOI:10.3389/fphys.2012.00460 · 3.50 Impact Factor
[Show abstract] [Hide abstract]
- "PEF graphs had been drawn and the diurnal variations had been calculated (the daily maximum minus the daily minimum divided by their mean), the interpretation of the PEF values being based on direct visual analysis and supported by the percentage decreases in PEF. When allocating patients into diagnostic categories of probability, we adopted the following principles: (1) PEF record compatible with OA = ¸20% diurnal variation on at least two work days and relatively more often on workdays than on non-workdays (Liss and Tarlo 1991; Tarlo et al. 2008); (2) PEF record suggestive of OA = no diurnal variations exceeding 20% but the lowest recordings on workdays, or a ¸20% change longitudinally across workdays with decreasing values toward the end of the work period; (3) PEF record not compatible with OA = <20% diurnal variation with no marked diVerence between the workdays and non-workdays; (4) PEF record indicating asthma lability = ¸20% diurnal variation both at and away from work. "
ABSTRACT: Damp and moldy indoor environments aggravate pre-existing asthma. Recent meta-analyses suggest that exposure to such environments may also induce new-onset asthma. We assessed the probability of molds being the cause of asthma in a patient series examined because of respiratory symptoms in relation to workplace dampness and molds. Altogether 694 such patients had been clinically assessed between 1995 and 2004. According to their histories, they had all been exposed to molds at work and had suffered from work-related lower respiratory symptoms. The investigations had included specific inhalation challenge (SIC) tests with mold extracts and serial peak expiratory flow (PEF) recordings. Using internationally recommended diagnostic criteria for occupational asthma (OA), we categorized the patients into three groups: probable, possible, and unlikely OA (156, 45, and 475 patients, respectively). The clinical details of 258 patients were analyzed, and their levels of microbial exposure were evaluated. The agreement between the serial PEF recordings and SIC tests (both being either positive or negative) was 56%. In the group of probable OA, mold sensitization was found in 20%. The level of exposure and sensitization to molds was associated with probable OA. At 6 months, the follow-up examinations of 136 patients with probable OA showed that the symptoms were persistent, and no improvement in spirometry was noted despite adequate treatment. Only 58% of the patients had returned to work. Exposure to damp and moldy workplaces can induce new-onset adult asthma. IgE mediation is a rare mechanism, whereas other mechanisms are unknown.International Archives of Occupational and Environmental Health 12/2010; 83(8):855-65. DOI:10.1007/s00420-010-0507-5 · 2.20 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Work-related asthma is common yet underdiagnosed. It is a significant cause of morbidity and socioeconomic loss. Diagnosis is often difficult, and requires a strong index of suspicion and careful investigation. The Canadian Thoracic Society has endorsed the recent American College of Chest Physicians consensus statement on work-related asthma. The present document illustrates the advised approach to diagnosis and management of work-related asthma using case-based examples of occupational asthma and work-exacerbated asthma. The main statements of advice from the American College of Chest Physicians consensus statement are reproduced with permission.Canadian respiratory journal: journal of the Canadian Thoracic Society 16(6):e57-61. · 1.66 Impact Factor