Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.     

Smoking-related interstitial lung diseases

Interstitial lung diseases (ILDs) encompass diverse clinicopathological disease entities ranging from idiopathic interstitial pneumonia (IIP) to interstitial pneumonia accompanied by collagen vascular diseases and diseases related to smoking, drug reactions, occupational environments, infections, and malignancies. Our focus is on the smoking-related interstitial lung diseases. Specifically, we focus on reports suggesting that chronic smoking is deeply involved in the disease pathogenesis and on reports suggesting that chronic smoking may influence the clinical course in terms of either disease severity or progression. Pulmonary Langerhans' cell granulomatosis (PLCG), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis with interstitial lung diseases (RB-ILD), interstitial pneumonia associated with rheumatoid arthritis, acute respiratory distress syndrome (ARDS), and idiopathic pulmonary fibrosis (IPF) are covered.     

Smoking-related emphysema and interstitial lung diseases

Smoking-related illnesses contribute to a large number of deaths in the industrialized world and their treatment comprises a substantial percentage of total healthcare dollars. The most common and most well-known smoking-related illnesses include chronic obstructive pulmonary disease, bronchogenic carcinoma, and ischemic heart disease. However, the role of cigarette smoking in the pathogenesis of other lung diseases is becoming increasingly apparent. Knowledge of both the histologic and radiographic manifestations of smoking-related lung disease is important to the radiologist as imaging findings can be nonspecific. Finally, correlation of imaging and clinical information may obviate the need for open lung biopsy.     

吸烟相关性肺间质纤维化

吸烟相关性肺间质纤维化(smoking-related interstitial fibrosis,SRIF)是近几年出现的新临床术语.与吸烟密切相关;症状相对较轻,病程进展缓慢;影像学特征缺乏特异性,高分辨率CT有助于临床诊断;病理特征鲜明,以肺泡间隔透明致密纤维化为特征,多伴有肺气肿;预后相对较好,有别于其他类型间质性肺病.本文就SRIF病理学特征、临床意义、诊断及鉴别诊断予以概述,以提高临床医务工作者对SRIF的认识.     

Smoking-related diseases: the importance of COPD.

SETTING: Smoking plays a major role in a variety of diseases. Despite a strong relationship between smoking and chronic obstructive pulmonary disease (COPD), cardiovascular disease and lung cancer attract greater attention. OBJECTIVE: To assess the burden of illness produced by smoking. DESIGN: Smoking-attributable risk (SAR) and smoking-attributable disease burden (mortality, morbidity, and cost) were estimated for four conditions: COPD, coronary heart disease (CHD), lung cancer, and stroke. RESULTS: Smoking-attributable deaths worldwide were: 1772 580 COPD, 1277 000 CHD, 822 150 lung cancer, and 788 580 stroke. Smoking-attributable disability adjusted life years (DALYs) were: 47 232 000 COPD, 18 106 000 CHD, and 11 052 000 stroke. US smokingattributable costs were: dollar 26.0 billion CHD, dollar 24.9 billion COPD, and dollar 9.0 billion stroke. US smoking-attributable annual hospitalizations were: 520 000 COPD, 460 000 CHD, and 183 000 stroke. CONCLUSIONS: Cardiovascular disease and lung cancer rank high in absolute estimates of disease burden. However, COPD has a more substantial smoking-attributable disease burden. COPD deserves more attention in the health care sector. Smoking cessation programs, pharmacological interruption of the pathophysiology of smoking-related COPD, and effective management of COPD should be key targets of intervention and research.     

Drug-induced interstitial lung diseases

Any discussion of drug-induced interstitial lung disease is fraught with the problem of having a syndrome in which information is composed predominantly of case reports. When the information is taken as a whole, however, the picture becomes clearer: (1) Some drugs can produce significant pulmonary toxicity; (2) the clinical history, physical examination, and chest roentgenogram are not unique or specific for drug-induced interstitial lung disease; and (3) the lung reacts in limited ways to various insults, producing pathologic changes that are not unique for drug-induced interstitial lung disease. The work of Crystal et al. has shed new light on interstitial lung disease. Their concept that the alveolitis is the key initiating step in interstitial lung disease fits with the pathologic findings in many situations of drug-induced interstitial lung disease. Furthermore, as they proposed, if the primary alveolitis has not progressed to derangement of alveolar structures, then the process can be reversed. This may explain the variable response seen with drug withdrawal and the use of corticosteroids. These concepts have not been extensively studied in drug-induced interstitial lung disease and this needs to be done to fully evaluate their ideas. A keen awareness of the potential for any drug to cause drug-induced interstitial lung disease can be of immense benefit to the patient, for early discontinuation of the agent is likely to increase the chance of reversing the pulmonary toxicity.     

Sellar plasmacytomas: a concise review

The diagnosis of a sellar plasmacytoma is often missed and is mistaken for a non functioning pituitary adenoma. We reviewed the literature on reported cases of sellar plasmacytoma in order to identify its clinical presentation, laboratory, radiological and pathological characteristics. We describe the management of these cases after the correct diagnosis was made and provide insight to preoperative diagnosis of this entity. Preoperative diagnosis may help avoid unnecessary surgical resection of an otherwise radiosensitive tumor. We also report and describe in detail a new case of sellar plasmacytoma that we have recently evaluated.     

Iron deficiency: a concise review

Iron deficiency is a major worldwide health problem. There is recent evidence that the anemia is only the last manifestation of the syndrome and that symptoms occur before the anemia is manifest. Advances in outlining the physiology of iron deficiency have been made, gaps remain in the current understanding. While oral iron supplement remains the mainstay, some indications for the intravenous administration have developed. This review will highlight the epidemiology, physiology, clinical presentation, and treatment options.     

Unclassifiable interstitial lung disease: A review

Accurate classification of interstitial lung disease (ILD) requires a multidisciplinary approach that incorporates input from an experienced respirologist, chest radiologist and lung pathologist. Despite a thorough multidisciplinary evaluation, up to 15% of ILD patients have unclassifiable ILD and cannot be given a specific diagnosis. The objectives of this review are to discuss the definition and features of unclassifiable ILD, identify the barriers to ILD classification and outline an approach to management of unclassifiable ILD. Several recent studies have described the characteristics of these patients; however, there are inconsistencies in the definition and terminology of unclassifiable ILD due to limited research in this population. Additional studies are required to determine the appropriate evaluation and management of patients with unclassifiable ILD.     

Smoking-related interstitial pneumonias and pulmonary Langerhans cell histiocytosis

The relationship between cigarette smoke and interstitial lung diseases (ILDs) is not clear. Respiratory bronchiolitis (RB), usually found as an incidental histologic abnormality in otherwise asymptomatic smokers, is characterized by the accumulation of cytoplasmic golden-brown-pigmented macrophages within respiratory bronchioles. A small proportion of smokers have a more exaggerated response that, in addition to the bronchiole-centered lesions, provokes interstitial and air space inflammation and fibrosis extending to the nearby alveoli. This set of histologic changes is called RB-ILD, and results in clinical symptoms. Desquamative interstitial pneumonia (DIP) is characterized by panlobular involvement, diffuse mild-to-moderate interstitial fibrosis, and massive alveolar filling with macrophages. It is well known that the histopathologic patterns of RB-ILD and DIP may overlap, and that the key features for differentiating these disorders are the distribution and the extent of the lesions: bronchiolocentric in RB-ILD and diffuse in DIP. It has been proposed that RB, RB-ILD, and DIP may be different components of the same histopathologic disease spectrum, representing various degrees of severity of the same process caused by chronic smoking, although this is still controversial. Pulmonary Langerhans' cell histiocytosis is also strongly related to cigarette smoking and is characterized by the proliferation of specific histiocytes, known as Langerhans' cells, and their infiltration of organ systems. Although RB, RB-ILD, DIP, and Pulmonary Langerhans' cell histiocytosis are considered as discrete entities of smokers, it is not infrequent to find a mixture of pathologic features rendering the histopathologic diagnosis difficult.     

Histological classification of interstitial lung diseases

The 2002 ATS/ERS consensus classification of idiopathic interstitial pneumonias standardizes definitions and criteria for classification and diagnosis of idiopathic interstitial pneumonias and replaces previous classifications. Based on clinico-radiologic-pathologic criteria seven entities were defined: idiopathic pulmonary fibrosis, nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia and lymphoid interstitial pneumonia. The following paper includes a brief overview of the histopathological diagnosis of these entities as compared to other diffuse interstitial pulmonary diseases and pulmonary manifestations of collagenvascular diseases.     

Approach of diffuse interstitial lung diseases

Diffuse interstitial lung diseases (DILD) are heterogeneous set of diseases affecting the interstitium of the lung. The etiologic factors may be known or unknown. The diagnosis is based on the disease history, findings of the physical and radiological examinations, physiological and bronchoscopic findings, the cyto- and/or histopathological findings of the bronchoscopic materials and surgical lung biopsy in some selected patients. The reader will find the definition, classification, general properties and clinical approach of DILD.     

Treatment in diffuse interstitial lung diseases

Diffuse interstitial lung diseases are parenchymal diseases of the lung with many various etiologies and most of which are idiopathic. The mainstays of the treatment are corticosteroids and immunosuppressants. This paper deals with the treatment of idiopathic interstitial pneumonias and sarcoidosis.     

Viral-induced inflammation in interstitial lung diseases

Viruses have long been implicated as either causative agents or propagators of inflammation in interstitial lung diseases. To date, culture of lung tissue specimens or bronchoalveolar lavage has failed to provide evidence of viable viral organisms. Indirect evidence comes from studies reporting serologic evidence of exposure to numerous viruses in individuals with a variety of interstitial lung diseases. A link between viral infection and interstitial lung diseases also has been suggested by some studies that amplified viral DNA from lung biopsy specimens. The lack of reproducibility of some of these studies suggests that some of these findings may have been false-positive results generated by the extreme sensitivity of the molecular methods used. Furthermore, amplification of viral genomic components from tissue specimens does not necessarily imply that the virus had a direct role in causing the lung injury. There is no definitive evidence that viruses participate in the pathogenesis of idiopathic pulmonary fibrosis, sarcoidosis, and Langerhans' cell histiocytosis. It is possible that some viruses may precipitate hypersensitivity pneumonitis in predisposed individuals, and occasional cases of uncommon interstitial lung diseases have been reported to occur during the course of well-documented viral infections, indicating that, at least in some situations, viruses may be the primary cause of interstitial lung disease. The lack of definitive evidence implicating viral infection as a cause of interstitial lung diseases does not rule out a potential role of viruses as a triggering event that may be important for the development of interstitial lung disease in predisposed individuals.     

Induced sputum in interstitial lung diseases

PURPOSE OF REVIEW: Induced sputum is a particularly useful procedure since it provides information on the cellular and molecular constituents in inflammation. Extensive work has demonstrated the application of induced sputum in the management of asthma, chronic obstructive pulmonary disease and chronic bronchitis, but less attention has been paid to its efficacy in diagnosing interstitial lung diseases. This review analyzes the applications of induced sputum in the assessment of sarcoidosis, nongranulomatous interstitial lung diseases, occupational lung diseases and other systemic diseases with or without lung involvement. RECENT FINDINGS: T cell subsets in induced sputum in combination with pulmonary function testing can serve as predictors with high specificity and sensitivity in diagnosing sarcoidosis, using multivariate logistic regression models which can be easily implemented in clinical practice. Differential cell counts in induced sputum are as useful as bronchoalveolar lavage for identifying neutrophilic inflammation in patients with nongranulomatous interstitial lung diseases (e.g. idiopathic pulmonary fibrosis) and detecting chronic rejection in bronchiolitis obliterans syndrome. Sputum analysis has also been shown to be a useful tool for diagnosing, assessing and monitoring occupational lung disorders. SUMMARY: We suggest integrating induced sputum technology to the well-established criteria for the diagnosis of interstitial lung diseases, especially when there are clinical contraindications for performing bronchoscopy or when tissue confirmation is absent for any reason.