Important issues in occupational asthma

Although there has been a dramatic increase in awareness about the contributions of the work environment to asthma, many aspects of this illness remain to be explored in further detail. This article focuses on issues that need to be better understood. Data are reported that describe newly recognized agents in the workplace that have been shown in a sophisticated manner to induce asthma. In addition, data that further describe the mechanisms of occupational asthma and information regarding the management of occupational asthma are given. Important problems yet to be resolved include whether those who develop occupational asthma from different agents are likely to have different outcomes, whether screening is likely to have a significant effect on the outcome (and, if so, what is the best approach to screening), and identification of a clear definition of the role of immunologic-mediated parameters as they relate to the initiation of asthma attributable to low molecular weight agents and patient outcome. There is little information about "safe" levels of exposure that protect all workers. Data (such as underlying specific immunologic or genetic markers) are lacking that might aid in predicting which workers are likely to be sensitized by low molecular weight agents. This abbreviated list of unresolved issues makes the study of occupational asthma a fertile field for research.     

Approaches to the diagnosis and management of occupational asthma amongst UK respiratory physicians

This study aimed to assess the approach to the diagnosis and management of occupational asthma amongst general (non-specialist) respiratory consultants in the UK. A random sample of 100 UK general respiratory physicians were invited to participate, and asked to provide information on their diagnostic approach to a case scenario of a patient with possible occupational asthma relating to flour exposure. Participation rates were 42% for the main part of the study. Less than half of consultants specifically reported they would ask whether symptoms improved away from work, and just over a third mentioned examining the patient. All of those interviewed recommended a chest X-ray, and 98% simple spirometry. Eighty-six per cent suggested measurement of serial peak flows, recorded for between 2 and 8 weeks, with measurements taken half-twelve hourly. Less than half advocated a specific flour allergy test, and almost one-quarter (23%) would not perform any immunological test at all. Once a diagnosis of occupational asthma was confirmed, less than two-thirds of those interviewed commented they would recommend some form of exposure reduction, and only 28% specifically stated they would offer compensation advice. The diagnosis of occupational asthma by general respiratory physicians within the UK lacks standardisation, and in some cases falls short of evidence-based best practise.     

Occupational asthma: a practical approach.

Although evaluation of possible occupational asthma may be complex, it can be pursued systematically by first assessing whether asthma is present, and then determining whether asthma is caused or triggered by the workplace or by alternative or confounding nonoccupational explanations. A detailed history is of great importance in raising suspicion of occupational asthma, but studies have shown that even detailed histories obtained by experienced specialists can lead to inaccurate conclusions about the presence or absence of occupational asthma. Consequently, objective measurements should be performed to establish the diagnosis of occupational asthma whenever possible. If the patient is still working in the workplace, work-related changes in spirometry or peak flow measurements can confirm the diagnosis. For occupational asthma from some airborne sensitizers, immediate-type skin testing or in vitro tests for specific IgE may establish sensitization. However, there is evidence that for some isocyanates, in vitro tests for specific IgG serum antibody levels correlate better with documented bronchospasm from isocyanate exposure, even though the IgG antibody is not thought to be pathogenic. Controlled, specific inhalation tests may be valuable, but they should be performed only under experienced medical supervision. Intervention should be focused on reducing or avoiding harmful workplace exposures so that permanent lung impairment and need for chronic medical treatment are avoided. Assessment of permanent impairment/disability from occupational asthma optimally should be determined 2 years after the removal from occupational exposure, when improvement has been shown to plateau and the patient will likely have reached maximal medical improvement.     

Pneumomediastinum is a Possible Acute Complication of Severe Occupational Asthma

Occupational asthma has been reported to be the most common chronic respiratory occupational disease in many developed countries, and as with other occupational lung diseases, occupational asthma is potentially preventable. We report the case of a 24-year-old baker who experienced pneumomediastinum as a consequence of workplace exposure. This is the first report of pneumomediastinum as an acute complication of occupational asthma, and it exemplarily shows that the lack of medical surveillance at the workplace may lead to an acute, although unusual, complication.     

Occupational asthma

Substantial epidemiologic and clinical evidence indicates that agents inhaled at work can induce asthma. In industrialized countries, occupational factors have been implicated in 9 to 15% of all cases of adult asthma. Work-related asthma includes (1) immunologic occupational asthma (OA), characterized by a latency period before the onset of symptoms; (2) nonimmunologic OA, which occurs after single or multiple exposures to high concentrations of irritant materials; (3) work-aggravated asthma, which is preexisting or concurrent asthma exacerbated by workplace exposures; and (4) variant syndromes. Assessment of the work environment has improved, making it possible to measure concentrations of several high- and low-molecular-weight agents in the workplace. The identification of host factors, polymorphisms, and candidate genes associated with OA is in progress and may improve our understanding of mechanisms involved in OA. A reliable diagnosis of OA should be confirmed by objective testing early after its onset. Removal of the worker from exposure to the causal agent and treatment with inhaled glucocorticoids lead to a better outcome. Finally, strategies for preventing OA should be implemented and their cost-effectiveness examined.     

Quality of occupational history assessments in working age adults with newly diagnosed asthma

BACKGROUND: Approximately 10 to 15% of new-onset asthma in adults is attributable to occupational exposure. The occupational history is the most important instrument in the diagnosis of occupational asthma (OA). STUDY OBJECTIVES: To assess the quality of occupational histories obtained by health-care providers and to measure the prevalence of clinician-diagnosed OA in a population at elevated risk for OA. SETTING: An academic US Department of Veteran Affairs medical center. STUDY POPULATION: One hundred ninety-seven adults (age range, 18 to 55 years) with newly diagnosed asthma who had completed pulmonary function testing (PFT) and a structured respiratory health questionnaire. MEASUREMENTS: We conducted a structured retrospective comparison of occupational respiratory health history documented by clinicians with data documented by patients on a structured questionnaire. We analyzed PFT results to assess physiologic impairment. We also conducted a structured examination of the actions taken by health-care providers based on their occupational history assessments. RESULTS: Patient self-reports of respiratory exposures and symptoms were common. A job title was documented by one or more clinicians in 75% of patient medical records. Additional occupational history data were charted much less frequently. A diagnosis of OA was made in only 2% of patients. Clinical action to address OA was documented for only one patient. CONCLUSIONS: Clinicians who manage adults with newly diagnosed asthma take incomplete occupational histories. We detected discordance between the occupational exposure histories documented by patients and those charted by clinicians. OA may go unrecognized and possibly undermanaged by clinicians.     

If you want to cure their asthma, ask about their job.

Occupational asthma is the most common occupational respiratory disorder and accounts for 15% of cases of adult asthma. A recent systematic review of evidence and management has clarified patient care for General Practitioners (GPs) who are key professionals in early diagnosis. Exposure to respirable agents in the work environment by means of dust, water aerosol or gases, causes an allergic sensitisation process in the respiratory tract. Initial rhinitis and night cough may progress to patterns of work-related wheezing from two weeks to six months after starting employment. The absence of symptoms while on holiday or sick leave suggests the diagnosis. Serial peak flow recordings show characteristic patterns. Smoking and atopy have a variable influence on whether a worker will develop the disease with exposure. Early identification and removal from exposure is essential for the worker since it improves prognosis. Other workers will be at risk, and occupational hygienists are required to measure and improve the working environment by means of ventilation and extraction of toxic fumes. Workplaces with workers who are at risk of occupational asthma, such as paint sprayers, food processors, welders and animal handlers, require health surveillance programmes for new and existing employees, as well as reinforcement of the more important primary safety measures of environmental monitoring and respiratory protection. All clinicians responsible for asthma management need to be aware of the potential for occupational asthma in new cases of adult asthma or unexplained worsening of pre-existing asthma. Specialist help is required to confirm the diagnosis, which has substantial legal and economic implications for the worker and their employer.     

The diagnosis and management of occupational asthma

INTRODUCTION: Occupational asthma (OA), with a latency period induced by multiple exposures, is characterized by immunological sensitization to the responsible agent, based on both an IgE mediated mechanisms and non specific bronchial hyper responsiveness. DIAGNOSTIC METHODS: In the diagnosis of OA, the medical history is obviously the starting-point. Onset of respiratory symptoms at work and resolution on vacation are indications of the diagnosis. After analysis of several publications, this element appears to have the best level of proof (grade 2+) according to the criteria of evidence-based medicine. A visit of the workplace, with the cooperation of the industrial physician, is essential to characterize the nature of the exposure. Positive immunological tests (skin tests and/or specific IgE) associated with objective criteria of symptoms related to work (modification of PEFR, lung function and/or nonspecific bronchial hyper responsiveness) will confirm the aetiological diagnosis of OA. Specific bronchial provocation tests performed in the laboratory allow the identification of new agents involved in OA and are necessary when other investigations are discordant or unavailable. OA needs a stepwise approach including induced sputum eosinophilic counts and measurements of exhaled nitric oxide. MANAGEMENT OF OA: OA requires removal from the workplace because persistence of exposure to respiratory sensitisers may lead to an increase and prolongation of asthma symptoms. However, removal from the workplace can have tremendous professional, financial and social consequences, and sometimes a compromise must be found with reduction of exposure by various methods combined with adequate treatment. The pharmacological treatment of patients with OA should be the same as for patients with non OA, the use of bronchodilators and corticoids depending on the severity of asthma. Concerning the medico-legal aspects, OA can be recognised as an occupational disease. In France OA is included in several tables of work-related diseases.     

¿Están verdaderamente basadas en la evidencia las guías sobre el asma? Un análisis crítico

Recent years have seen a growing reliance on "evidence-based" guidelines or consensus statements, in which rigorous, explicit methods are used to translate the complex findings of scientific research into operational recommendations for medical care. Various factors can affect the validity of the conclusions they express, however. The purpose of this review was to compare the levels of evidence supporting treatments for acute asthma in adults according to 3 of the most important guidelines. It seems that even though these guidelines are based on an approach that is more or less rigorous, there are considerable gaps and inconsistencies that compromise their validity. Our main sources of information should therefore be those that apply the best research designs, namely randomized controlled trials or meta-analyses of such trials with consistent results and a low probability of bias.     

Controversies in epidemiology of occupational asthma.

Epidemiology is the study of the distribution, determinants and outcome of disease. In this article, the recently acquired knowledge of the epidemiology of occupational asthma is described, as well as current areas of controversy. Incidence figures obtained from field studies in high-risk workplaces, medicolegal statistics and sentinel programmes indicate that approximately 10% of adult-onset asthma is attributable to the workplace. The strategy to identify cases through questionnaires and tools that address functional, immunological and physiopathological issues needs to be improved. Although few in number and limited to a handful of workplaces, cohort studies found that the risk of developing occupational asthma is determined less by individual susceptibility (e.g. atopy, tobacco smoking, human leukocyte antigen phenotype) and more by the level of exposure to its causes; in general, the higher the exposure, the greater the risk, and, by implication, lowering the level of exposure reduces the incidence of disease. Occupational asthma can be used as a satisfactory model for the development of adult-onset asthma. There is a great need to develop intervention strategies through adequate surveillance programmes in high-risk workplaces.     

Hospital Attendances and Acute Admissions Preceding a Diagnosis of Occupational Asthma

Lung - Occupational exposures are a common cause of adult-onset asthma; rapid removal from exposure to the causative agent offers the best chance of a good outcome. Despite this, occupational...     

Population-Based Screening or Case Detection for Asthma: Are We Ready?

Asthma is a prevalent health problem for which there are effective treatments. By identifying people with asthma and treating them effectively, the burden of asthma in the United States should be reduced. Detecting people with asthma through screening programs seems a logical approach to the problem. This article assesses our readiness for population-based screening and case detection programs for asthma and examines these activities in relation to World Health Organization criteria for determining the appropriateness of screening programs. Given that, at this time, a number of the criteria have not been met, we conclude that population-based approaches to screening and case detection of asthma are of unproven benefit and need further research. A more appropriate focus may be to ensure that all people who are diagnosed with asthma receive appropriate medical care.     

Follow-up of subjects occupationally exposed to asbestos, what are the objectives, the benefits, and the possible risks?

The follow-up of workers occupationally exposed to asbestos has two possible beneficial effects: (1) individually, both medical by screening for diseases related to asbestos and social by notification of occupational disease and/or compensation from the indemnity funds for asbestos victims; (2) collectively, by the establishment of epidemiological surveillance (follow-up of cohorts) and evaluation of the impact of follow-up in terms of health benefits and compensation. The respiratory disorders related to asbestos are: cancer (malignant pleural mesothelioma and bronchial carcinoma), asbestos-related pulmonary fibrosis, and pleural disease (plaques, pleural fibrosis and benign pleurisy). In the light of the data currently available and the effectiveness of the tools used, medical and public health benefits of screening for mesothelioma have not been demonstrated. The early diagnosis of primary bronchial carcinoma can theoretically improve the prognosis of the subjects screened, particularly by identification of stage I disease on CT (pulmonary nodules). This is a common finding but there are a large number of false-positives. While we await the results of several international randomised trials, the benefits of a screening programme for bronchial carcinoma in the population at risk have not been demonstrated. There is no effective treatment for asbestosis but this is an independent risk factor for bronchial carcinoma and it is evidence of heavy asbestos exposure. Stopping smoking in subjects suffering from asbestosis will reduce the incidence of bronchial carcinoma. There is no effective treatment for asbestos-related benign pleural diseases but these are markers of exposure. The presence of pleural plaques has not been shown to be an aetiological factor for thoracic cancers. Post-occupational follow-up may involve risks to health, particularly repeated irradiation and invasive diagnostic procedures. It is also necessary to consider the psychological consequences inherent in all screening programmes. In conclusion, post-occupational follow-up might reduce the mortality of lung cancer by screening for localised disease and its incidence by a targeted anti-smoking programme. The theoretical benefits, that have not yet been demonstrated, have to be seen in perspective with the risks to physical and psychological health related to both screening and diagnostic procedures.     

Occupational asthma

PURPOSE OF REVIEW: The scientific literature on occupational asthma is steadily increasing and no longer only describes case reports with prevalence figures and limited physiopathologic and immunologic data. Prospective cohort studies are currently carried out with relevant incidence figures and risk factors. Genetic susceptibility is explored. New diagnostic means are described. Surveillance programs are conducted and preventive measures are proposed. RECENT FINDINGS: A relevant account was published on the respiratory consequences (irritant-induced asthma, a type of occupational asthma) of exposure of firefighters at the World Trade Center site. Glutathione-S-transferase appears to be an interesting susceptibility gene for occupational asthma as a result of isocyanates. Inflammation caused by neutrophils and not only by eosinophils is more often associated with occupational asthma. Examination of induced sputum and assessment of exhaled nitric oxide are becoming useful diagnostic tools. Cleaners are at increased risk of developing occupational asthma, although the causal agents are unknown. Surveillance programs currently combine strategies that aim to reduce exposure and identify cases early. SUMMARY: New scientific information provides better, accurate figures on the frequency of occupational asthma and on risk factors, proposes relevant diagnostic tools more directly related to the physiopathology of the disease, and suggests effective surveillance programs in high-risk workplaces.     

The scope of cell phones in diabetes management in developing country health care settings

Diabetes has emerged as a major public health concern in developing nations. Health systems in most developing countries are yet to integrate effective prevention and control programs for diabetes into routine health care services. Given the inadequate human resources and underfunctioning health systems, we need novel and innovative approaches to combat diabetes in developing-country settings. In this regard, the tremendous advances in telecommunication technology, particularly cell phones, can be harnessed to improve diabetes care. Cell phones could serve as a tool for collecting information on surveillance, service delivery, evidence-based care, management, and supply systems pertaining to diabetes from primary care settings in addition to providing health messages as part of diabetes education. As a screening/diagnostic tool for diabetes, cell phones can aid the health workers in undertaking screening and diagnostic and follow-up care for diabetes in the community. Cell phones are also capable of acting as a vehicle for continuing medical education; a decision support system for evidence-based management; and a tool for patient education, self-management, and compliance. However, for widespread use, we need robust evaluations of cell phone applications in existing practices and appropriate interventions in diabetes.     

强化培训对塞拉利昂军队医护人员传染病职业防护的干预效果

目的探讨强化培训在塞拉利昂医院及其基层医疗点医护人员传染病职业暴露防护认知与技能的干预效果。方法选择塞拉利昂某大型综合医院——A医院及基层2个医疗点的医护人员,通过问卷调查,了解传染病职业暴露防护认知与技能的情况;通过预分析反馈的问题,开展针对性的理论授课,实际操作演练等强化培训,然后再次针对该人群进行问卷调查,比较干预前后的效果。结果医护人员培训干预后职业风险认知和实践技能总体评分明显高于自身干预前的水平(P均0.05)。但无论干预前还是干预后,基层医院医护人员职业风险认知和实践技能总体评分均低于A医院。结论对医护人员进行强化培训干预,整体提高了当地医护人员传染病职业防护认知与技能水平,但基层医疗点条件差、人员素质偏低,实际操作技能还须进一步强化和督导。     

Occupational asthma in a highly industrialized region of UK: report from a local surveillance scheme

Estimates of the incidence of occupational asthma may be derived from surveillance schemes established in several countries. SHIELD is a voluntary surveillance scheme for occupational asthma in the West Midlands, a highly industrialized region of UK. The aim of this study was to estimate the general and specific incidence of occupational asthma in the West Midlands in 1990-97. The annual incidence was 41.2/million. There was a two fold difference in the incidence by sex (male 59.6/million/yr; female 27.4/million/yr). The highest annual incidence (53.2/million) was observed in the age group 45-64 yr (male) and 45-59 yr (female). Spray painters were the occupation at the highest risk of developing occupational asthma, followed by electroplaters, rubber and plastic workers, bakery workers and moulders. Although the percentage of reported cases was low among healthcare workers, there was a raising trend. Isocyanates still remained the most common causative agents with 190 (17.3%) out of the total 1097 cases reported to the surveillance scheme in seven years. There was a decrease in the reported cases due to colophony (9.5% to 4.6%), flour & wheat (8.9% to 4.9%). There was an increase of reported cases due to latex (0.4% to 4.9%) and glutaraldehyde (1.3% to 5.6%). The serial mesurement of peak expiratory flow at and away from work was the most used method of diagnosis to confirm the occupational cause of asthma. Specific bronchial challenge test with the occupational agents were used when the serial measurement of peak expiratory flow was not able to confirm undoubtdely the diagnostic suspicion or when it was difficult to identify the possible causative agent due to multiple exposures in the workplace. Following diagnosis, 24% of the patients were moved away from exposure within the same workplace in 1997, compared to 15.8% in the previous years. Those remaining exposed to the causative agent in the same workplace decreased from 28.3% to 17.7% between 1990-97. The surveillance of occupational asthma trough this voluntary scheme has allowed to monitor the incidence of the disease in the region and to identify clusters of cases, where control measures are a priority.     

Controversies in vascular screening art versus science

Whether or not to screen asymptomatic members of the general public for various forms of vascular disease is a controversial issue with huge medical, social, and financial ramifications. This article reviews several criteria for determining the appropriateness of vascular screening, including: (1) is it possible to detect occult vascular disease ;early'?; (2) what should we screen for, and how should we do it?; (3) who should be screened?; and (4) what standards for vascular screening should be set? While some of these controversies may ultimately be resolvable using an evidence-based approach, it is apparent that there are issues which will not be amenable to strict scientific analysis. Individualized approaches to screening will therefore remain the rule for the foreseeable future.