Recognizing the pleura in asbestos-related pleuropulmonary disease: Known and new manifestations of pleural fibrosis.

Pleural thickening (PT) is a major consequence of exposure to all fiber types of asbestos. In recent decades, it is more prevalent than parenchymal asbestosis. Its manifestations occupy a full clinical and radiographic spectrum. Six major manifestations can be identified: (a) acute pleuritis generally with effusion; (b) diffuse PT or fibrous pleuritis; (c) rounded atelectasis; (d) circumscribed PT or plaques; (e) chronic pleuritic pain; and (f) mesothelioma. Review of the experience of workers and community members in Libby, MT to asbestiform fibers in vermiculite has confirmed the appearance of these previously known benign and malignant asbestos-related diseases as well as a unique pleuropulmonary disease characterized as lamellar PT and associated with progressive decline in pulmonary function and pleuritic pain. Despite previous literature asserting that PT represents a marker for asbestos exposure without significant effect on pulmonary function and physiology, the experience of Libby amphibole (LA) disease, along with other studies, indicates that PT plays a role in declining vital capacity in those with prolonged or unusual exposures such as those arising from LA.

Fluoro-edenite non-neoplastic diseases in Biancavilla (Sicily, Italy): pleural plaques and/or pneumoconiosis?

BACKGROUND: A mesothelioma cluster in Biancavilla (Sicily, Italy), drew attention to fluoro-edenite, a fibre classified by International Agency for Research on Cancer as carcinogenic to humans. Significant excesses in mortality and morbidity were observed for respiratory diseases and a significant excess of pneumoconiosis hospitalizations was reported. OBJECTIVE: Aim of this study is to assess the characters of the lung damage in Biancavilla residents hospitalized with pneumoconiosis or asbestosis diagnoses. METHODOLOGY: Medical records, available radiographs and computed tomography scans were collected. The obtained imaging was reviewed by a panel of three specialists and focused on pleural and parenchymal abnormalities. Cases with an ILO-BIT or ICOERD score equal or greater than 2 were considered positive for a pneumoconiosis-like damage, cases with a score lower than 2 or insufficient quality of imaging were considered inconclusive. If no pneumoconiotic aspects were present the cases were classified as negative. RESULTS: Out of 38 cases, diagnostic imaging for 25 cases were found. Ten cases out of 25 showed asbestosis-like features, nine subjects were considered negative. In six patients' results were inconclusive. CONCLUSIONS: Asbestosis-like features were substantiated in Biancavilla residents without known occupational exposure to asbestos. Further studies to estimate population respiratory health are required. Experimental studies on the fibrogenic potential of fluoro-edenite are needed.

Asbestos-associated pulmonary disease.

PURPOSE OF REVIEW: Exposure to asbestos can cause both benign and malignant, pulmonary and pleural diseases. In the current era of low asbestos exposure, it is critical to be aware of complications from asbestos exposure; as they often arise after decades of exposure, asbestos-related pulmonary complications include asbestosis, pleural plaques, diffuse pleural thickening, benign asbestos-related pleural effusions and malignant pleural mesothelioma. RECENT FINDINGS: Multiple recent studies are featured in this review, including a study evaluating imaging characteristics of asbestos with other fibrotic lung diseases, a study that quantified pleural plaques on computed tomography imaging and its impact on pulmonary function, a study that examined the risk of lung cancer with pleural plaques among two large cohorts and a review of nonasbestos causes of malignant mesothelioma. SUMMARY: Asbestos-related pulmonary and pleural diseases continue to cause significant morbidity and mortality. This review summarizes the current advances in this field and highlights areas that need additional research.

High-resolution computed tomography features of asbestosis versus fibrotic hypersensitivity pneumonitis: an observational study.

BACKGROUND: Asbestosis and fibrotic hypersensitivity pneumonitis (FHP) share the pathogenetic mechanisms induced bronchiolocentric fibrotic process secondary to inhalation exposure. Under the occupational and environmental mixed exposures, asbestosis and FHP are needed to make the differential diagnoses on high-resolution computed tomography (HRCT), especially in the countries still using asbestos. The study aimed to analyze the HRCT features of asbestosis versus FHP. METHODS: The patients with asbestosis or with HP were sequentially recruited in this comparative study at Beijing Chaoyang Hospital between January 2006 and December 2016. Patients' clinical data were obtained from a predesigned charts. The international classification of HRCT for occupational and environmental respiratory diseases was used to categorize chest imaging findings in patients. The calculation of test statistics was used to compare the imaging features of asbestosis and FHP. RESULTS: 341 patients with asbestosis and 158 patients with HP were sequentially recruited, among which 204 patients with asbestosis and 74 patients with FHP were eligible for data analysis. Patients with asbestosis were older and had a longer latent period until disease manifestation than those with FHP. Asbestosis was characterized by irregular and/or linear opacities, with lower lung preponderance, accompanied by ground-glass opacities and mosaic attenuation. Notably, 98.5% of patients with asbestosis showed benign pleural abnormalities, and 39.7% of these patients had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. Abnormalities of the mediastinal and diaphragmatic pleura were observed only in cases of asbestosis, and this finding showed high specificity for the diagnosis for asbestosis compared with that for FHP. Subpleural dots or diaphragmatic pleural abnormalities showed moderate sensitivity and high specificity for diagnosis of asbestosis compared with that for FHP. Interobserver reliability was good for evaluation of imaging findings including honeycombing, pleural calcification, lymphadenectasis, and lymph node calcification. CONCLUSIONS: HRCT-based imaging findings can distinguish between asbestosis and FHP to a certain extent, particularly with regard to subpleural dots and diaphragmatic pleural abnormalities that characterize the former.

[Chest high-resolution CT features analysis in predicting the progression of asbestosis].

Objective: To analyze the radiological characteristics of chest high-resolution computed tomography (HRCT) of patients with asbestosis, and to investigate the signs of predicting the disease progression of asbestosis. Methods: A prospective method was used to enroll 68 patients with asbestosis who were regularly followed up from 2013 to 2016. The radiological characteristics of patients with asbestosis were described by the International Classification of HRCT for Occupational and Environmental Respiratory Diseases (ICOERD) , and the differences between patients with and without progression were compared during the observation period. The Cox proportional hazards regression model was used to analyze the chest HRCT radiological signs predicting the progression of asbestosis. Results: The study included 68 patients with asbestosis aged (65.5±7.8) years old, of which 64.7% (44/68) were female, 29.4% (20/68) had a history of smoking. There was no significant difference in age, sex, smoking and asbestos exposure between patients with progressive asbestosis (20.6%, 14/68) and patients without progressive asbestosis (79.4%, 54/68) (P>0.05) . Chest HRCT of patients with asbestosis showed irregular and/or linear opacities, of which 5.9% (4/68) were accompanied by honeycombing. Irregular and/or linear opacities were mainly lower lung preponderant, often accompanied with ground glass opacity and mosaic perfusion. 98.5% (67/68) had pleural abnormalities, of which 39.7% (27/68) had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. The analysis of multivariable Cox proportional hazard regression showed that the risk of the progression of asbestosis was increased with higher irregular and/or linears opacities cores (HR=1.184, 95%CI: 1.012-1.384, P=0.034) and the appearance of honeycombing (HR=6.488, 95%CI: 1.447-29.097, P=0.015) . Conclusion: The irregular and/or linear opacities scores and honeycombing on chest HRCT are independent influencing factors for predicting the disease progression of asbestosis.

Environmental asbestos exposure and nonmalignant pleural findings: a retrospective evaluation of a five-year chest CT repository.

This registry-based case-control study aimed to assess the association between asbestos deposits in the birthplace and/or residence and nonmalignant pleural findings, namely pleural plaques (PPs) and pleural thickening (PT), on chest CT scans. In total, 39,472 CT scans obtained over five years in a tertiary referral hospital in Ankara, Turkey, were evaluated. Cases involving patients with PP (n = 537), PT (n = 263), PP&PT (n = 69), and controls (n = 543) from the same study base without those conditions were included. Each case group was compared to controls using unconditional logistic regression. The presence of asbestos deposits in the district of birthplace (adjusted OR = 2.13, 95% CI: 1.35-3.37) and both birthplace and residence (aOR = 4.32, 95% CI: 2.26-8.27) was significantly related to the PPs. As the importance of environmental asbestos exposure in Turkey continues, future prospective studies could contribute to developing screening strategies.

Chest high-resolution CT features analysis in predicting the progression of asbestosis / 中华劳动卫生职业病杂志

Objective: To analyze the radiological characteristics of chest high-resolution computed tomography (HRCT) of patients with asbestosis, and to investigate the signs of predicting the disease progression of asbestosis. Methods: A prospective method was used to enroll 68 patients with asbestosis who were regularly followed up from 2013 to 2016. The radiological characteristics of patients with asbestosis were described by the International Classification of HRCT for Occupational and Environmental Respiratory Diseases (ICOERD) , and the differences between patients with and without progression were compared during the observation period. The Cox proportional hazards regression model was used to analyze the chest HRCT radiological signs predicting the progression of asbestosis. Results: The study included 68 patients with asbestosis aged (65.5±7.8) years old, of which 64.7% (44/68) were female, 29.4% (20/68) had a history of smoking. There was no significant difference in age, sex, smoking and asbestos exposure between patients with progressive asbestosis (20.6%, 14/68) and patients without progressive asbestosis (79.4%, 54/68) (P>0.05) . Chest HRCT of patients with asbestosis showed irregular and/or linear opacities, of which 5.9% (4/68) were accompanied by honeycombing. Irregular and/or linear opacities were mainly lower lung preponderant, often accompanied with ground glass opacity and mosaic perfusion. 98.5% (67/68) had pleural abnormalities, of which 39.7% (27/68) had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. The analysis of multivariable Cox proportional hazard regression showed that the risk of the progression of asbestosis was increased with higher irregular and/or linears opacities cores (HR=1.184, 95%CI: 1.012-1.384, P=0.034) and the appearance of honeycombing (HR=6.488, 95%CI: 1.447-29.097, P=0.015) . Conclusion: The irregular and/or linear opacities scores and honeycombing on chest HRCT are independent influencing factors for predicting the disease progression of asbestosis.

Low dose CT detected interstitial lung abnormalities in a population with low asbestos exposure.

BACKGROUND: The use of low dose CT (LDCT) chest is becoming more widespread in occupationally exposed populations. There is a knowledge gap as to heterogeneity in severity and the natural course of asbestosis after low levels of exposure. This study reports the characteristics of LDCT-detected interstitial lung abnormalities (ILA). METHODS: The Asbestos Review Program offers annual LDCT, health assessments, and pulmonary function tests to an asbestos-exposed cohort. Asbestosis was defined using the Helsinki Consensus statement and the presence of ILA defined using a protocol for occupational CT reports. At least two of three pulmonary function tests: forced expiratory volume in 1 s (FEV1 );​ forced vital capacity (FVC); and diffusion capacity for carbon monoxide (DLco) were required for analysis of physiological decline. RESULTS: From 1513 cases, radiological ILA was present in 485 (32%). The cohort was 83.5% male with a median age of 68.3 years and a median (IQR) asbestos exposure of 0.7 (0.09-2.32) fiber/ml-year. A mixed occupation, mixed asbestos fiber cohort comprised the majority of the cohort (65.8%). Of those with ILA, 40 (8.2%) had an FVC decline of ≥10% and 30 (6.2%) had a DLco decline of ≥15% per year. Time since first exposure, increasing tobacco exposure and reported dyspnea were independently associated with the presence of ILA. CONCLUSIONS: In this population with relatively low asbestos exposure, LDCT-detected ILA that fits criteria for asbestosis is common, but physiological decline is not. This mild chronic stable phenotype of asbestos-associated ILA contrasts with the traditionally accepted views that asbestosis requires high exposures.

Chemo-physical properties of asbestos bodies in human lung tissues studied at the nano-scale by non-invasive, label free x-ray imaging and spectroscopic techniques.

In the lungs, asbestos develops an Fe-rich coating (Asbestos Body, AB) that becomes the actual interface between the foreign fibers and the host organism. Conventional approaches to study ABs require an invasive sample preparation that can alter them. In this work, a novel combination of x-ray tomography and spectroscopy allowed studying unaltered lung tissue samples with chrysotile and crocidolite asbestos. The thickness and mass density maps of the ABs obtained by x-ray tomography were used to derive a truly quantitative elemental analysis from scanning x-ray fluorescence spectroscopy data. The average mass density of the ABs is compatible with that of highly loaded ferritin, or hemosiderin. The composition of all ABs analyzed was similar, with only minor differences in the relative elemental fractions. Silicon concentration decreased in the core-to-rim direction, indicating a possible partial dissolution of the inner fiber. The Fe content in the ABs was higher than that possibly contained in chrysotile and crocidolite. This finding opens two opposite scenarios, the first with Fe coming from the fiber bulk and concentrating on the surface as long as the fiber dissolves, the second where the Fe that takes part to the formation of the AB originates from the host organism Fe-pool.

Asbestosis Mimicking Metastatic Lung Cancer: Case Report.

The clinical diagnosis of asbestosis is primarily based on chest radiographic evidence of pleural thickening and interstitial fibrosis combined with a history of exposure to asbestos. We report herein the case of a 65-year-old man with asbestosis pathologically diagnosed after surgical lung biopsy. He had a work history including farming, cementing, and casting and was admitted with dyspnea. Chest computed tomography revealed multiple well-defined nodules in both lungs and a 4.1 cm peribronchial consolidation with fibrotic changes in the right lower lobe. We suspected metastatic lung cancer and video-assisted thoracoscopic biopsy was performed in the lung lesion of the right lower lobe. Asbestosis was confirmed following histological examination. The patient is currently completing outpatient visits without significant changes.

Clinical and radiological criteria for the differential diagnosis between asbestosis and idiopathic pulmonary fibrosis: Application in two cases.

INTRODUCTION: Idiopathic pulmonary fibrosis (IPF) and asbestosis are pulmonary interstitial diseases that may present overlapping clinical aspects in the full-blown phase of the disease. For both clinical entities the gold standard for diagnosis is histological examination, but its execution poses ethical problems, especially when performed for preventive or forensic purposes. OBJECTIVE: To evaluate the application of internationally accepted clinical, anamnestic and radiological criteria for differential diagnosis between asbestosis and IPF, and to assess the ability to discriminate between the two diseases. Even if clinically similar, the two diseases present extremely different prognostic and therapeutic perspectives. METHODS: Two clinical cases of IPF are reported, in which the differential diagnosis was made by studying occupational exposure to asbestos, the onset and progression of clinical symptoms, and the identification of specific radiological elements by means of chest High Resolution Computed Tomography (HRCT). RESULTS: The diagnosis of IPF could be made on the basis of the absence of significant exposure to asbestos, the early onset and rapid progression of dyspnea and restrictive ventilatory defects, in association with a pulmonary radiological pattern characterized by peculiar elements such as honeycombing. DISCUSSION: The diagnostic procedure adopted to make a differential diagnosis with asbestosis provides practical clinical elements facilitating the differentiation between the two forms of pulmonary fibrosis, a fundamental aspect of the activity of the occupational physician.

Characteristics of asbestos fibers in lung tissue from occupational and environmental asbestos exposure of lung cancer patients in Busan, Korea.

The Asbestos Injury Relief Act in Korea requires that asbestos exposure be assessed through clinical examination and chest computed tomography (CT). However, a more specific measurement of asbestos characteristics in the lung tissue may be appropriate. We aimed to investigate the asbestos burden and characterize asbestos fibers in patients with lung cancer and ultimately assess the relationship between occupational and environmental asbestos exposure and lung cancer in Korea. We evaluated 37 lung cancer patients (LCPs) from Busan. The factors affecting asbestos burden in LCPs were analyzed using a multiple regression analysis. History of asbestos exposure (environmental/occupational), male sex, and old age were the main factors affecting asbestos burden in lung tissues of LCPs. These factors had an approximate 37% adjusted coefficient of determination. There was a significant difference in the length of asbestos fibers (4.06-37.6 µm vs. 4.26-91.7 µm) and aspect ratio (4.5-151.9 vs. 5.6-735.6) between those who were occupationally exposed to asbestos and those who were environmentally exposed (P < 0.01). Therefore, both environmental/occupational exposure to asbestos should be strongly managed to reduce the risk of lung cancer, and exposure should be assessed according to the characteristics of asbestos fibers in the lung tissue.

Imaging and imagination in the diagnostics of asbestosis.

Two cases of asbestosis diagnosed on the basis of anamnestic, clinical, and instrumental criteria, were not confirmed by forensic autopsy ordered by the public prosecutor to ascertain the cause of death. The two cases demonstrate that a suggestive working history can be misleading, in the absence of clear radiological signs and histopathological findings, and that asbestosis must be diagnosed following the criteria consolidated in the scientific literature, as any diagnostic errors can have serious legal consequences.

Asbestos-related diseases.

Knowledge of asbestos-related diseases has been accumulating for over one hundred years as the industrial value of asbestos was recognised for the strength of its fibres and their resistance to destruction, resulting in increasing production and use until the multiple health effects have become apparent. Deposition in the lung parenchyma results in an inflammatory/progressively fibrotic response, with impaired gas exchange and reduced lung compliance ('asbestosis'), causing progressive dyspnoea and respiratory failure for which only palliation is indicated, although anti-fibrotic agents used for idiopathic usual interstitial pneumonitis remain to be evaluated. Benign pleural effusion, diffuse pleural fibrosis (occasionally with associated rolled atelectasis) and pleural plaques are the non-malignant pleural diseases that result from fibres reaching the pleura. But the main issues that led to the ban on asbestos in industry are those of malignancy: lung cancer, malignant mesothelioma (MM) of the pleura and MM of the peritoneum. Bronchogenic carcinoma risk from asbestos exposure is dose-dependent and multiplies the risk attributable to tobacco smoking. The principles of treatment are as for all cases of lung cancer. Low-dose computed tomography screening of exposed people can detect early-stage, non-small cell cancers, with improved survival. The amphibole varieties of asbestos are much more potent causes of MM than chrysotile, and the risk increases exponentially for 40-50 years following first exposure. As MM is non-resectable and poorly responsive to chemotherapy and radiotherapy, curative treatment is not possible and screening not justified.

Pulmonary Function and CT Scan Imaging at Low-Level Occupational Exposureto Asbestos.

Background: In spite of the reduced exposure level, and its ban in numerous countries, compensation claims for asbestos-related diseases are far from decreasing. Methods: We used retrospective exposure assessment techniques to explore respiratory function and a computerized tomography (CT) scan in relation to past asbestos exposure in 115 male workers retired from an acrylic and polyester fiber plant. Based, on detailed information on exposure circumstances, we reconstructed a cumulative exposure estimate for each patient. Results: Time-weighted average exposure in our study population was 0.24 fibers/ml (95% confidence inteval (CI) 0.19-0.29), and the average cumulative exposure was 4.51 fibers/mL-years (95% CI 3.95-5.07). Exposure was elevated among maintenance workers, compared to other jobs (p = 0.00001). Respiratory function parameters did not vary in relation to the exposure estimates, nor to CT scan results. Risk of interstitial fibrosis showed a significant upward trend (Wald test for trend = 2.62, p = 0.009) with cumulative exposure to asbestos; risk associated with 5.26 fibers/mL-years or more, was 8-fold (95% CI 1.18-54.5). Conclusions: Our results suggest that a CT scan can detect pleuro-parenchymal lung alterations at asbestos exposure levels lower than previously thought, in absence of respiratory impairment. Further studies are required to validate our techniques of retrospective assessment of asbestos exposure.

[Asbestos and its effects on health of Icelanders - review].

Asbestos are crystallized silicate minerals that form fibers with different structures and characteristics. Asbestos fibers are very durable and can tolerate very high temperatures. Therefore it was common to use asbestos as a fire retardants, heat insulation and where high temperature is used. Asbestos has been banned in Iceland from 1983 but can still be found in large amounts in buildings, ships and hot water pipes. Large amounts of asbestos were imported in the years before the ban but diminished soon to almost nothing today. Needle or filamentous shaped dust is released when working with asbestos. It is this dust that is dangerous for health. The latent time from exposure to disease can be up to forty years. Asbestos reaches the lungs via inhalation and can cause asbestosis that is a form of lung fibrosis with slow progression. Asbestos can also cause benign pleural effusions, pleural plaques and diffuse pleural thickening. Asbestos is a carcinogen. Lung cancer is most common but asbestos is also a risk factor for cancers of other organs. Mesothelioma is most common in the pleura but can be seen in other membranes. The incidence of these tumors is high in Iceland and is still increasing among males. Of all the European countries mortality is highest in Iceland. It is important for physicians to include asbestos exposure in the differential diagnosis of lung diseases and when lung cancer is diagnosed.

Diagnosis of asbestos-related lung diseases.

INTRODUCTION: The diagnosis of lung disease in asbestos-exposed individuals is a process that not only requires a detailed occupational and tobacco smoking history, but the correlation with physical signs, appropriate imaging, detailed lung function assessment and histology/cytology when required. Worldwide, the total quantity of asbestos mined is static, having decreased dramatically in developed countries but increased in countries where there is no restriction on mining: for example, Russia, China, Brazil, and Kazakhstan. The predominant diagnostic challenge in most cases of possible asbestos-related disease is the significant interval between exposure and development of the disease. Also challenging is the estimation of an individual's risk of disease, not least because asbestos-induced malignancy can be rapidly fatal, and, in the case of lung cancer, early detection can lead to treatment with curative intent. Areas covered: Discussion of quantitative asbestos exposure estimation and risk assessment, selection of the most appropriate imaging modality and frequency of imaging. Expert commentary: Consideration of the future for asbestos-related lung disease includes screening those at highest risk particularly in relation to ongoing mining operations and the management of in-situ asbestos. In the future, screening programs designed with estimation of risk of malignancy, based on quantitative estimates of asbestos exposure, and smoking history are indicated.