Occupational lung disease. Part 1. Identifying work-related asthma and other disorders

Lung disease is prevalent among workers. Occupational toxicant exposures have an important role in many cases of lung disease seen in workers. Most occupational lung diseases can be grouped into one of four categories that include asthma and the diffuse parenchymal lung diseases (also known as interstitial lung disease). Asthma is especially prevalent among workers, and occupational factors should be explored in all adults with asthma. A worker's visit to a primary care physician often represents the first opportunity to establish a link between lung disease and the workplace. Therefore, it is important to maintain a high level of suspicion about the potential etiologic role of workplace exposures, especially in new cases of lung disease among workers. Although accumulating absolute proof of work-relatedness may not be possible, a brief occupational history and physical evaluation can provide substantial evidence to effectively rule out, or begin to rule in, a link between work and lung disease.     

Work-related asthma.

Work-related asthma accounts for at least 10 percent of all cases of adult asthma. Work-related asthma includes work aggravation of preexisting asthma and new-onset asthma induced by occupational exposure. Occupational exposure to very high concentrations of an irritant substance can produce reactive airway dysfunction syndrome, while exposure to allergenic substances can result in allergic occupational asthma. An important step in the diagnosis of work-related asthma is recognition by the physician of the work relatedness of the illness. A thorough history can elucidate the work relation and etiology. Objective tests, including pulmonary function, nonspecific and specific bronchial hyperresponsiveness, serial peak expiratory flow rates, and skin allergies, should be performed to confirm the diagnosis of asthma and demonstrate a work correlation. Treatment for occupational asthma--use of anti-inflammatory medications such as inhaled steroids and bronchodilators--is the same as that for nonoccupational asthma. Prevention is an integral part of good medical management. In patients with work-aggravated or irritant-induced asthma, reduction of exposure to aggravating factors is essential. In patients with allergic occupational asthma, exposure should be eliminated because exposure to even minute concentrations of the offending agent can trigger a potentially fatal allergic reaction.     

Concise guidance: diagnosis, management and prevention of occupational asthma

This concise guidance, prepared for physicians, summarises the British Occupational Health Research Foundation guideline for the prevention, identification and management of occupational asthma. Approximately one in six people of working age who develop asthma have work-related asthma, where work has either caused or aggravated their disease. Physicians who assess working adults with asthma need to ask the patient about their job and the materials they work with, and be aware of those that carry particular risks; they should also ask whether symptoms improve regularly on days away from work. A diagnosis of occupational asthma (ie asthma caused by work) should not be made on the basis of history alone, but be supported by immunological and physiological investigations of proven diagnostic benefit. Following a validated diagnosis of occupational asthma, physicians should recommend early avoidance of further exposure, because this offers the best chance of complete recovery. If appropriate and timely interventions are not taken, the prognosis of occupational asthma is poor, with only approximately one-third of workers achieving full symptomatic recovery.     

A guide to the diagnosis and treatment of occupational asthma

Occupational asthma is the most prevalent form of occupational lung disease in industrialized nations. As increasing numbers of new chemicals are produced and new manufacturing processes are introduced, the variety of environments in which individuals may become exposed to respiratory sensitizers and irritants makes diagnosing and treating this illness even more challenging. In addition to adverse pulmonary effects, the diagnosis of occupational asthma may bring with it negative social and financial implications that may ultimately affect the patient's quality of life. For this reason, it is important for clinicians to recognize work-related respiratory symptoms early on in their course, maintain a high clinical suspicion for an occupational cause in the diagnostic work-up of asthma, and have a high degree of certainty in the diagnosis. While a number of classification schemes have been proposed to simplify the diagnostic approach to occupational asthma, the inciting factors typically involve sensitization (often by an IgE mechanism), direct airway inflammation, various pharmacologic responses, or irritant reflex pathways. Clinicians must first document the presence of asthma, then establish a relationship between asthma and the work-place. The occupational history is the key diagnostic tool, and clinical suspicions may be evaluated further by serial peak expiratory flow measurements, nonspecific hypersensitivity challenges with histamine or methacholine, collaboration with industrial/occupational hygienists to obtain workplace exposure measurements, and specific challenge testing at tertiary referral centers providing specialized laboratories. Removal from the inciting exposure is the mainstay of therapy, and pharmacologic treatment of patients with occupational asthma is similar to the treatment of patients with other forms of asthma.     

Asbestos-related lung disease

The inhalation of asbestos fibers may lead to a number of respiratory diseases, including lung cancer, asbestosis, pleural plaques, benign pleural effusion, and malignant mesothelioma. Although exposure is now regulated, patients continue to present with these diseases because of the long latent period between exposure and clinical disease. Presenting signs and symptoms tend to be nonspecific; thus, the occupational history helps guide clinical suspicion. High-risk populations include persons in construction trades, boilermakers, shipyard workers, railroad workers, and U.S. Navy veterans. Every effort should be made to minimize ongoing exposure. Patients with a history of significant asbestos exposure may warrant diagnostic testing and follow-up assessment, although it is unclear whether this improves outcomes. Patients with significant exposure and dyspnea should have chest radiography and spirometry. The prognosis depends on the specific disease entity. Asbestosis generally progresses slowly, whereas malignant mesothelioma has an extremely poor prognosis. The treatment of patients with asbestos exposure and lung cancer is identical to that of any patient with lung cancer. Because exposure to cigarette smoke increases the risk of developing lung cancer in patients with a history of asbestos exposure, smoking cessation is essential. Patients with asbestosis or lung cancer should receive influenza and pneumococcal vaccinations.     

Occupational asthma.

Occupational asthma is recognized as the most common form of occupational lung disease. Over 200 causative substances have been described. Major cases of occupational asthma are discussed along with valuable diagnostic approaches. Early diagnosis and removal of the patient from workplace exposure to the causative substance can prevent progression to severe asthma.     

Diagnosis of interstitial lung diseases

Interstitial lung diseases (ILDs), a broad heterogeneous group of parenchymal lung disorders, can be classified into those with known and unknown causes. The definitions and diagnostic criteria for several major forms of ILDs have been revised in recent years. Although well over 100 distinct entities of ILDs are recognized, a limited number of disorders, including idiopathic pulmonary fibrosis, sarcoidosis, and connective tissue disease-related ILDs, account for most ILDs encountered clinically. In evaluating patients with suspected ILD, the clinician should confirm the presence of the disease and then try to determine its underlying cause or recognized clinicopathologic syndrome. Clues from the medical history along with the clinical context and radiologic findings provide the initial basis for prioritizing diagnostic possibilities for a patient with ILD. High-resolution computed tomography of the chest has become an invaluable tool in the diagnostic process. A confident diagnosis can sometimes be made on the basis of high-resolution computed tomography and clinical context. Serologic testing can be helpful in selected cases. Histopathologic findings procured through bronchoscopic or surgical lung biopsy are often needed in deriving a specific diagnosis. An accurate prognosis and optimal treatment strategy for patients with ILDs depend on an accurate diagnosis, one guided by recent advances in our understanding of the causes and pathogenetic mechanisms of ILDs.     

Work-related asthma and latex allergy. Sorting out the types, causes, and consequences.

Work-related asthma now has clear definitions based on criteria agreed upon by the American College of Chest Physicians. The clinician should suspect occupational asthma, irritant-induced asthma, or work-aggravated asthma in adults with new-onset asthma or asthma symptoms that worsen during work, after work (late allergic response), or over the course of workdays. The possible cause should be sought, and a skin test or immunoassay should be performed, if possible,to he;lp detect sensation. Workup als o includes objective documentation of worsening of symptoms and airway obstruction during occupational exposure. If this information is inconclusive, an inhalation challenge may be considered. Medical management is the same as for nonoccupational asthma, but cessation of exposure to the specific agent is necessary to improve long-term diagnosis. Latex allergy and latex-induced asthma are becoming more common in the workplace, particularly in the healthcare field. No commercially available standard serum or skin test are available for diagnosis. The principal treatment is avoidance of latex, which can be achieved in most cases without extensive changes to the workplace.     

Transthoracic sonography of diffuse parenchymal lung disease: the role of comet tail artifacts.

OBJECTIVE: The value of transthoracic sonography in diffuse parenchymal lung disease is not established. This prospective study was conducted to analyze pleural and parenchymal alterations in patients with diffuse parenchymal lung disease by transthoracic sonography and to compare the results with the findings of a control group. METHODS: Fifty-three patients with diffuse parenchymal lung disease and 35 control subjects underwent transthoracic sonography for assessment of (1) basal pleural effusion, (2) the presence and number of comet tail artifacts, (3) thickening, (4) an irregular, fragmented pleural line, and (5) subpleural alterations. RESULTS: Basal pleural effusion was revealed in 37.7% of the patients with diffuse parenchymal lung disease (0% of the control subjects; P < .001), and 98.1% had multiple (>6 per scan) comet tail artifacts (14.3% of the control subjects; P < .001). Only a few artifacts (< or = 6 per scan; P < .001) were shown in 85.7% of the control subjects. All the control subjects had strongly localized comet tail artifacts and no thickened pleural line (84.9% of patients; P < .001). In 98.1 % of the patients, an irregular, fragmented pleural surface could be detected (82.8% of the control subjects; P < .05). Subpleural alterations were found in 37.7% of the patients and in 8.6% of the control subjects (P < .001). CONCLUSIONS: Diffuse parenchymal lung disease should be considered if multiple comet tail artifacts distributed over the whole surface of the lung together with a thickened and irregular, fragmented pleural line are visible. Transthoracic sonography may reflect the distribution of pleural involvement and may show subpleural alterations.     

Drug-induced lung disease.

Since there are no diagnostic studies to confirm the presence of a drug-induced lung reaction the physician will make a correct diagnosis only if he is aware of the drugs which have been identified to cause pulmonary reactions and their specific manifestations. Failure to recognize a drug-induced lung disease can lead to significant morbidity and in some cases mortality. The major drug-induced lung diseases are reviewed, the drugs being presented in the context of their clinical use and the reactions on the basis of common pathogenetic mechanisms.     

内科胸腔镜肺活检对弥漫性间质性肺疾病诊断价值及安全性分析

目的探讨内科胸腔镜肺活检对弥漫性间质性肺疾病患者的诊断价值及安全性。方法回顾性分析35例内科胸腔镜肺活检的弥漫性间质性肺疾病患者临床及病理诊断资料。结果 31例患者获病理确诊,确诊率88.6%(31/35),其中普通型间质性肺炎(UIP)10例,肺结核6例,肺泡细胞癌4例,非特异性间质性肺炎(NSIP)、隐源性机化性肺炎(COP)各3例,肺泡蛋白沉着症(PAP)2例,韦格纳肉芽肿病(WG)、急性间质性肺炎(AIP)和淋巴管肌瘤病(LAM)各1例。术后并发症3例(8.6%),其中肺部感染合并呼吸衰竭2例,特发性肺间质纤维化急性加重1例,导致死亡2例(5.7%)。结论内科胸腔镜肺活检是诊断弥漫性间质性肺疾病安全有效的方法。     

Interstitial lung disease

The interstitial lung diseases are comprised of a group of pulmonary disorders characterized clinically by diffuse infiltrates on the chest radiograph and histologically by distortion of the gas exchanging portion of the lung. The physiologic correlates are restriction of lung volumes and impaired oxygenation. The term "interstitial" when applied to these diseases is actually a misnomer because it implies that the inflammatory process is limited specifically to the area between the alveolar epithelial and capillary endothelial basement membranes. The diseases currently grouped as "interstitial" also frequently involve the alveolar epithelium, alveolar space, pulmonary microvasculature, and less commonly, the respiratory bronchioles, larger airways, and even the pleura. The enormous differential diagnosis of interstitial lung disease can be made manageable by understanding that pneumoconiosis, drug-induced disease, and hypersensitivity pneumonitis account for over 80% of the responsible entities and can usually be identified from the patient's history. The nine remaining diseases/disease categories include: sarcoidosis, idiopathic pulmonary fibrosis, bronchiolitis obliterans-organizing pneumonia, histiocytosis X, chronic eosinophilic pneumonia, collagen vascular disease-associated interstitial lung disease, granulomatous vasculitis (Wegener's granulomatosis, Churg-Strauss syndrome, lymphomatoid granulomatosis), Goodpasture's syndrome, and pulmonary alveolar proteinosis. The diagnosis of a specific interstitial lung disease can be made via various means including the patient's history, specific serologies, bronchoalveolar lavage, transbronchial biopsy, and biopsy of extrathoracic tissues or open lung biopsy. A directed diagnostic approach can be formulated based on an understanding of these techniques and a thorough knowledge of the clinical presentations and specific diagnostic criteria for each of the major diseases. This monograph will serve as a guide for the clinician to use in evaluating and treating patients with interstitial lung disease. We begin by reviewing the clinical presentation, diagnostic criteria, and management of specific interstitial lung diseases excluding pulmonary infection, neoplasm, and sarcoidosis. Pneumoconiosis and drug-induced syndromes are not discussed in detail, but the agents responsible and pertinent exposures are presented in tabular form in the discussion of the general diagnostic approach.     

Selected topics related to occupational exposures. Part V. Occupational cardiovascular disease

Cardiovascular disease is common in the United States. Several occupational exposures, such as carbon disulfide and organic nitrates, are believed to cause occupational cardiovascular disease. In addition some other agents, such as lead and cadmium, may indirectly cause cardiovascular disease through their effects on blood pressure. For other agents (ie, carbon monoxide, solvents, and chlorofluorocarbons), acute exposure and high levels may cause cardiovascular disease but may not cause cardiovascular disease through long-term or low levels. A primary care physician who has a patient with a new or unstable cardiovascular disease should obtain an occupational history to assess whether occupational exposures may be playing a role. An occupational history may indicate potential cardiovascular risks. Such risks can include exposure to certain chemicals and metals, physical factors, exertion, or psychological stress. The primary care physician should be able to assess the situation and advise the patient, as well as the employer, about restrictions or accommodations that may need to be made.     

Is it asthma or COPD? The answer determines proper therapy for chronic airflow obstruction

Evaluation and diagnosis of obstructive lung disease call for careful history taking to distinguish asthma from chronic obstructive pulmonary disease (COPD). A history of atopy and intermittent, reactive symptoms points toward a diagnosis of asthma, whereas smoking and advanced age are more indicative of COPD. Clinical features such as cough and wheezing, especially in light of patient history, can be suggestive but are not definitive. Spirometry, usually performed in the primary care setting, is the key diagnostic tool that distinguishes patients with asthma from patients with COPD. In this article, the authors outline an approach to differential diagnosis of asthma and COPD that should result in better evaluation, therapy, and quality of life for these patients.     

Making the diagnosis of occupational asthma: when to suspect it and what to do

Although most adult patients seen by a clinician are employed, medical school curricula and residency training rarely cover occupational exposures and resultant diseases, even common ones that are encountered in a typical medical practice. This primer on occupational asthma is intended for the primary care clinician to provide the essential tools to diagnose and treat airways disease in the workplace. Using a case vignette format, we review the basic approach to suspecting and establishing a diagnosis of occupational asthma and address the thornier question of what to do about it. After reviewing this primer, the reader will be able to routinely include occupational asthma as part of the differential diagnoses in the adult patient with new or worsened asthma.     

Diagnosing occupational lung disease a practical guide to the occupational pulmonary history for the primary care practitioner

A well-executed occupational pulmonary history should be part of the evaluation of workers presenting with respiratory illnesses or symptoms. In this article, we review the scope of occupational lung disease and detail the essential elements of the occupational pulmonary history. The authors have stated that they do not have a significant financial interest or other relationship with any product manufacturer or provider of services discussed in this article. The authors also do not discuss the use of off-label products, which includes unlabeled, unapproved, or investigative products or devices.     

Just what the court ordered

PREVIEW

Evaluation and diagnosis of obstructive lung disease call for careful history taking to distinguish asthma from chronic obstructive pulmonary disease (COPD). A history of atopy and intermittent, reactive symptoms points toward a diagnosis of asthma, whereas smoking and advanced age are more indicative of COPD. Clinical features such as cough and wheezing, especially in light of patient history, can be suggestive but are not definitive. Spirometry, usually performed in the primary care setting, is the key diagnostic tool that distinguishes patients with asthma from patients with COPD. In this article, the authors outline an approach to differential diagnosis of asthma and COPD that should result in better evaluation, therapy, and quality of life for these patients.     

Diagnosis: Chronic kidney disease, now what!

The occupational health nurse can play an important role in supporting employees with CKD and ESRD by recognizing risk factors such as diabetes and hypertension associated with CKD. The occupational health nurse should encourage compliance with treatment regimens that retard or delay progression of kidney disease into the next stage, especially blood pressure and glucose control. When employees are in need of diagnostic testing, the occupational health nurse can describe the testing procedures such as laboratory values, ultrasounds, and biopsies, and explain the five stages of CKD. The occupational health nurse can assist employees in Stage 4 or 5 CKD in deciding on a treatment option modality that best suits their individual lifestyles, after they have seen a nephrologist and kidney patient educator. In addition, the occupational health nurse can guide employees with difficult lifestyle changes and provide support during the adjustment process. The occupational health nurse also can play a key role in facilitating and coordinating those changes with the renal social worker. Together they can explore available resources, such as the NKF, the American Association of Kidney Patients, and kidneydirections.com. See the Sidebar on pages 295 to 296 for other available resources. Kidney disease can be a devastating diagnosis. Support and education are key to a successful lifestyle transition. Employees who have CKD and work with an occupational health nurse who is informed about their disease and its stages of progression can benefit from educational processes that create informed choices to delay or retard the progression of their renal disease.     

Occupational lung diseases

Clinical evaluation of a patient with occupational lung disease requires determining the pathophysiologic process, identifying the agent that is or was responsible, determining the prognosis and level of disability, assessing how the disease can be controlled or limited, and investigating the extent to which other workers may be affected. These conditions include the pneumoconioses, toxic inhalation, occupational asthma, hypersensitivity pneumonitis, industrial bronchitis, fume fevers and cancer. The family physician is in a good position to recognize these problems in the community.