Chest x-ray has low sensitivity to detect silicosis in artificial stone benchtop industry workers.

BACKGROUND AND OBJECTIVE: Chest x-ray (CXR) remains a core component of health monitoring guidelines for workers at risk of exposure to crystalline silica. There has however been a lack of evidence regarding the sensitivity of CXR to detect silicosis in artificial stone benchtop industry workers. METHODS: Paired CXR and high-resolution computed tomography (HRCT) images were acquired from 110 artificial stone benchtop industry workers. Blinded to the clinical diagnosis, each CXR and HRCT was independently read by two thoracic radiologists from a panel of seven, in accordance with International Labour Office (ILO) methodology for CXR and International Classification of HRCT for Occupational and Environmental Respiratory Diseases. Accuracy of screening positive (ILO major category 1, 2 or 3) and negative (ILO major category 0) CXRs were compared with identification of radiological features of silicosis on HRCT. RESULTS: CXR was positive for silicosis in 27/110 (24.5%) workers and HRCT in 40/110 (36.4%). Of the 83 with a negative CXR (ILO category 0), 15 (18.1%) had silicosis on HRCT. All 11 workers with ILO category 2 or 3 CXRs had silicosis on HRCT. In 99 workers ILO category 0 or 1 CXRs, the sensitivity of screening positive CXR compared to silicosis identified by HRCT was 48% (95%CI 29-68) and specificity 97% (90-100). CONCLUSION: Compared to HRCT, sensitivity of CXR was low but specificity was high. Reliance on CXR for health monitoring would provide false reassurance for many workers, delay management and underestimate the prevalence of silicosis in the artificial stone benchtop industry.

Accuracy of chest x-ray screening of silica-exposed miners for tuberculosis.

BACKGROUND: The World Health Organization recommends systematic chest X-ray (CXR) screening for tuberculosis (TB) in silica-exposed workers. However, evidence on the accuracy of CXR screening in such populations is lacking. AIMS: To measure the accuracy of CXR screening for active TB in silica-exposed miners, in a population with a high prevalence of silicosis, post-TB lung disease and HIV. METHODS: A secondary analysis of data from a miner screening programme in Lesotho was undertaken. We measured the performance of CXR (in participants with and without cough) for 'abnormalities suggestive of TB' against Xpert MTB/RIF (Xpert). The sample size was 2572 and positive Xpert prevalence was 3%. RESULTS: CXR alone had high sensitivity (0.93, 95% confidence interval [CI] 0.87-0.99), but low specificity (0.41, 95% CI 0.39-0.42). Requiring cough and a positive CXR increased specificity (0.79, 95% CI 0.77-0.81), resulting in reduced sensitivity (0.41, 95% CI 0.30-0.52). There was no difference in CXR accuracy by HIV status. However, specificity was markedly reduced in the presence of silicosis (from 0.70, 95% CI 0.68-0.72, to 0.03, 95% CI 0.02-0.04) or past TB history (from 0.59, 95% CI 0.56-0.62 to 0.27, 95% CI 0.25-0.29). Throughout, positive predictive value remained very low (5%) and negative predictive value very high (99%). CONCLUSIONS: CXR screening accurately identifies TB-negative CXRs in this population, but post-TB lung disease and silicosis would result in a high proportion of Xpert-negative referrals and an increased risk of unneeded empirical treatment. Adapted screening algorithms, practitioner training and digital access to previous mining CXRs are needed.

Dose-response relationship between lung function and chest imaging response to silica exposures in artificial stone manufacturing workers.

BACKGROUND: Occupational exposure to artificial stone, a popular material used for countertops, can cause accelerated silicosis, but the precise relationship between silica dose and disease development is unclear. OBJECTIVES: This study evaluated the impact of silica exposure on lung function and chest imaging in artificial stone manufacturing workers. METHODS: Questionnaire and spirometry assessments were administered to workers in two plants. A high-exposure subset underwent further evaluation, including chest CT and DLco. Weighting factors, assigned as proxies for silica exposure, were based on work tasks. Individual cumulative exposures were estimated using area concentration measurements and time spent in specific areas. Exposure-response associations were analyzed using linear and logistic regression models. RESULTS: Among 65 participants, the mean cumulative silica exposure was 3.61 mg/m3-year (range 0.0001 to 44.4). Each 1 mg/m3-year increase was associated with a 0.46% reduction in FVC, a 0.45% reduction in FEV1, and increased lung function abnormality risk (aOR = 1.27, 95% CI = 1.03-1.56). Weighting factors correlated with cumulative exposures (Spearman correlation = 0.59, p < 0.0001), and weighted tenure was associated with lung function abnormalities (aOR = 1.04, 95% CI = 1.01-1.09). Of 37 high-exposure workers, 19 underwent chest CT, with 12 (63%) showing abnormal opacities. Combining respiratory symptoms, lung function, and chest X-ray achieved 91.7% sensitivity and 75% specificity for predicting chest CT abnormalities. CONCLUSION: Lung function and chest CT abnormalities occur commonly in artificial stone workers. For high-exposure individuals, abnormalities on health screening could prompt further chest CT examination to facilitate early silicosis detection.

Accelerated silicosis in sandblasters: Pathology, mineralogy, and clinical correlates.

BACKGROUND: With increasing reports of accelerated and acute silicosis, PMF, and autoimmune disease among coal miners and silica-exposed countertop workers, we present previously incompletely-described pulmonary pathology of accelerated silicosis and correlations with mineralogy, radiography, and disease progression in 46 Texas oilfield pipe sandblasters who were biopsied between 1988 and 1995. METHODS: Worker examinations included pulmonary function tests, chest X-ray (CXR), high-resolution computed tomography (HRCT), and Gallium-67 scans. Quantitative mineralogic analysis of pulmonary parenchymal burden of silica, silicates, and metal particles used scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM EDS). RESULTS: Workers had clinical deterioration after <10 years exposure in dusty workplaces. Although initial CXR was normal in 54%, Gallium-67 scans were positive in 68% of those with normal CXR, indicating pulmonary inflammation. The histology of accelerated silicosis is diffuse interstitial infiltration of macrophages filled with weakly birefringent particles with or without silicotic nodules or alveolar proteinosis. Lung silica concentrations were among the highest in our database, showing a dose-response relationship with CXR, HRCT, and pathologic changes (macrophages, fibrosis, and silicotic nodules). Radiographic scores and diffusing capacity worsened during observation. Silica exposure was intensified, patients presented younger, with shorter exposure, more severe clinical abnormalities, higher lung particle burdens, and more rapid progression in a subset of patients exposed to recycled blasting sand. CONCLUSIONS: Accelerated silicosis may present with a normal CXR despite significant histopathology. Multivariable analyses showed silica, and not other particles, is the driver of observed radiologic, physiologic, and histologic outcomes. Eliminating this preventable disease requires higher physician, public health, and societal awareness.

[A rare case: Erasmus syndrome and tuberculosis]. / Un caso poco frecuente: síndrome de Erasmus y tuberculosis.

We present the case of a 35-year-old male patient, sandblaster for eight years, recently diagnosed with pulmonary tuberculosis and systemic sclerosis, who was admitted with dyspnea and poor general condition. Chest X-ray showed a grade I pneumothorax, and on the chest tomography he presented confluent hyperdense masses associated with a pattern of non- specific interstitial pneumonia (NSIP), findings compatible with complicated silicosis. Due to the advanced clinical stage, neither invasive diagnostic test nor pulmonary function test could be performed. Initial treatment included placement of a pleural drainage tube, antituberculosis treatment and chronic home oxygen. The patient was referred to the interstitial disease and rheumatology departments for multidisciplinary management, although the infectious condition contraindicated the possibility of immunosuppressive treatment. The patient eventually died under palliative care. Silica inhalation is the cause of silicosis, but it is also implicated in the development of systemic sclerosis (Erasmus syndrome) and although they share a common risk factor, it is rare to find both diseases coexisting. We present the case of a young patient in whom both diseases presented aggressively, with the aim of highlighting the importance of actively searching for expositional diseases and associated conditions.

Presentamos el caso de un hombre de 35 años, arenador durante ocho años, con diagnóstico reciente de tuberculosis pulmonar y esclerosis sistémica, que ingresó por cuadro de disnea y mal estado general. Se realizó radiografía de tórax donde se evidenció neumotórax grado I, en la tomografía de tórax, también presentó masas hiperdensas confluyentes, asociadas a un patrón de neumonía intersticial no especifica (NSIP), hallazgos compatibles con silicosis pulmonar complicada. Debido al avanzado estadio clínico, no pudieron realizarse estudios diagnósticos invasivos ni estudios de función pulmonar. Como tratamiento inicial se colocó un tubo de avenamiento pleural, se realizó tratamiento antifímico y se indicó oxigenoterapia crónica domiciliaria. Se remitió al paciente a consultorios de enfermedades intersticiales y reumatología para un manejo multidisciplinario, aunque el cuadro infeccioso contraindicó la posibilidad de un tratamiento inmunosupresor. Finalmente, el paciente falleció bajo cuidados paliativos. La inhalación de sílice es la causa de la silicosis, pero también está implicada en el desarrollo de la esclerosis sistémica (síndrome de Erasmus) y aunque comparten un factor de riesgo común, es raro encontrar ambas enfermedades coexistiendo. Presentamos el caso de un paciente joven donde ambas condiciones se presentaron de manera agresiva, con el objetivo de remarcar la importancia de la búsqueda activa de las enfermedades por exposición y sus condiciones asociadas.

Elimination of tuberculosis requires prior control of silicosis including sub-radiological silicosis.

India is committed to the elimination of tuberculosis by 2025. But its achievement appears to be difficult as India has a huge burden of silicosis as well as sub-radiological silicosis, which was never given its required attention. Silicotic subjects are highly vulnerable to pulmonary tuberculosis due to the progressive decline of lung immunity. A study among vulnerable glass factory workers in Firozabad, Uttar Pradesh, revealed that silicotic workers were 7.5 times more at risk of pulmonary tuberculosis compared to non-silicotic subjects. Since India has a huge burden of silicosis and sub-radiological silicosis, the elimination of tuberculosis needs prior attention on silicosis. This article may be viewed as an eye-opener for understanding the necessity of dual control of both silicosis as well as tuberculosis by integrating both together.

[Evaluation of right ventricular function using two-dimensional speckle tracking echocardiography and analysis of the risk factors for right ventricular dysfunction in patients with silicosis].

Objective: To evaluate the right ventricular function using two-dimensional speckle tracking echocardiography (2-D STE) and analyze the associated risk factors of right ventricular dysfunction in patients with silicosis. Methods: All 104 patients with silicosis treated in the Department of Occupational Medicine and Toxicology in Beijing Chao-Yang Hospital, Capital Medical University from May 2021 to September 2022 were enrolled in this study in October 2022. The clinical information of patients such as general data, arterial blood gas analysis and pulmonary function test were collected. The right ventricular function of patients was evaluated by 2-D STE-derived right ventricular free wall longitudinal strain (RVFWLS) and conventional echocardiographic-derived parameters, including right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE) and doppler tissue imaging-derived tricuspid lateral annular systolic velocity (S'), respectively. Based on their RVFWLS, the patients were divided into right ventricular dysfunction group and normal right ventricular function group. Risk factors for right ventricular dysfunction in patients with silicosis were analyzed using binary logistic regression analysis. Results: A total of 104 silicosis patients were enrolled, with aneverage age (65.52±11.18) years old, among whom including 57 cases diagnosed with stage Ⅰ/Ⅱ silicosis and 47 cases diagnosed with stage Ⅲ silicosis. 26 (25.00%) patients concurrent right ventricular dysfunction. The abnormal rates of RVFAC, TAPSE and S' in patients were 16.35% (17 cases), 21.15% (22 cases) and 6.73% (7 cases), respectively. The RVFAC and TAPSE in right ventricular dysfunction group were lower than those in normal right ventricular function group, and the incidence of pulmonary arterial systolic pressure ≥36 mmHg was higher than that in normal right ventricular function group (P<0.05). Logistic regression analysis showed that arterial partial pressure of oxygen (OR=0.932, 95%CI: 0.885-0.981, P=0.007) was the protective factor, and the forced expiratory volume in 1 second (FEV(1)) /forced vital capacity (FVC) ratio<70% (OR=5.484, 95%CI: 1.049-28.662, P=0.044) and stage Ⅲ silicosis (OR=6.343, 95%CI: 1.698-23.697, P=0.007) were the risk factors for silicosis patients concurrent right ventricular dysfunction. Conclusion: The incidence of right ventricular dysfunction is higher in patients with stage Ⅲ silicosis than that in patients with stage Ⅰ/Ⅱ silicosis. Using 2-D STE can help the early detection of silicosis with right ventricular dysfunction. Hypoxemia, airflow limitation and the stage Ⅲ silicosis are the risk factors for silicosis patients concurrent right ventricular dysfunction.

Prevalence and risk factors for silicosis among a large cohort of stone benchtop industry workers.

OBJECTIVES: High silica content artificial stone has been found to be associated with silicosis among stone benchtop industry (SBI) workers. The objectives of this study were to determine the prevalence of and risk factors for silicosis among a large cohort of screened SBI workers, and determine the reliability of respiratory function testing (RFT) and chest x-ray (CXR) as screening tests in this industry. METHODS: Subjects were recruited from a health screening programme available to all SBI workers in Victoria, Australia. Workers undertook primary screening, including an International Labour Office (ILO) classified CXR, and subject to prespecified criteria, also underwent secondary screening including high-resolution CT (HRCT) chest and respiratory physician assessment. RESULTS: Among 544 SBI workers screened, 95% worked with artificial stone and 86.2% were exposed to dry processing of stone. Seventy-six per cent (414) required secondary screening, among whom 117 (28.2%) were diagnosed with silicosis (median age at diagnosis 42.1 years (IQR 34.8-49.7)), and all were male. In secondary screening, silicosis was associated with longer SBI career duration (12 vs 8 years), older age, lower body mass index and smoking. In those with silicosis, forced vital capacity was below the lower limit of normal in only 14% and diffusion capacity for carbon monoxide in 13%. Thirty-six (39.6%) of those with simple silicosis on chest HRCT had an ILO category 0 CXR. CONCLUSION: Screening this large cohort of SBI workers identified exposure to dry processing of stone was common and the prevalence of silicosis was high. Compared with HRCT chest, CXR and RFTs had limited value in screening this high-risk population.

Silica associated systemic sclerosis: an occupational health hazard.

A middle-aged male working in the sandblasting and stone-cutting industry was brought to the medicine department with skin tightness, dysphagia and discolouration of the skin for the last 1 year. On examination, he had skin thickening over the face and the extremities with restricted mouth opening. His hands were cold and showed peripheral cyanosis. Systemic examination was suggestive of diffuse cutaneous systemic sclerosis, further confirmed by the antinuclear antibody testing. Further, CT of the chest showed mediastinal lymphadenopathy with eggshell calcification and interstitial fibrosis consistent with silicosis and fibrotic non-specific interstitial pneumonitis. The patient was started on pulse monthly cyclophosphamide for six cycles, and steroids were given for 4 weeks and tapered. Tadalafil and amlodipine were given for his pulmonary artery hypertension and Raynaud's phenomenon, respectively. This case also highlights the importance of periodic screening of the workers exposed to silica dust to prevent silicosis.

Accuracy of Computer-Aided Detection of Occupational Lung Disease: Silicosis and Pulmonary Tuberculosis in Ex-Miners from the South African Gold Mines.

BACKGROUND: Computer-aided detection (CAD) of pulmonary tuberculosis (TB) and silicosis among ex-miners from the South African gold mines has the potential to ease the backlog of lung examinations in clinical screening and medical adjudication for miners' compensation. This study aimed to determine whether CAD systems developed to date primarily for TB were able to identify TB (without distinction between prior and active disease) and silicosis (or "other abnormality") in this population. METHODS: A total of 501 chest X-rays (CXRs) from a screening programme were submitted to two commercial CAD systems for detection of "any abnormality", TB (any) and silicosis. The outcomes were tested against the readings of occupational medicine specialists with experience in reading miners' CXRs. Accuracy of CAD against the readers was calculated as the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. Sensitivity and specificity were derived using a threshold requiring at least 90% sensitivity. RESULTS: One system was able to detect silicosis and/or TB with high AUCs (>0.85) against both readers, and specificity > 70% in most of the comparisons. The other system was able to detect "any abnormality" and TB with high AUCs, but with specificity < 70%. CONCLUSION: CAD systems have the potential to come close to expert readers in the identification of TB and silicosis in this population. The findings underscore the need for CAD systems to be developed and validated in specific use-case settings.

A 44-year-old stone worker with progressive dyspnea: lessons from a new twist on an old foe.

Silicosis is typically an indolent lung disease caused by long-standing occupational exposure to respirable crystalline silica, classically in professions such as sandblasting and mining.  An increasingly popular industry that has earned particular interest because of its association with silicosis is customization and installation of artificial stone countertops for domestic applications. In addition to causing a spike in cases of chronic and accelerated silicosis, both quite familiar to respiratory clinicians, outbreaks of artificial stone silicosis have brought to the fore a historically rare entity known as acute silicosis, or silicoproteinosis, a more rapid presentation of the disease. Failure to suspect this uncommon condition can lead to diagnostic confusion and therefore ineffective treatment as was true initially of the patient we describe herein.  The case description is followed by a clinical, radiological, and pathological overview of acute artificial stone silicosis (or silicoproteinosis), which is an emerging pneumoconiosis with sparse coverage in the literature to date.  This case also adds to the few existing reports on the use of therapeutic whole lung lavage for silicoproteinosis.

Diagnostic challenges of radiological opacities in silicosis - case reports.

Occupational exposure to crystalline silica dust in the workplace can cause lung damage (silicosis, chronic airflow limitation and lung cancer). Silicosis results from the fibrotic reaction to the deposition of inhaled crystalline silica dust in the lung tissue. Even though many coalmines and foundries have closed, crystalline silica is still widely used, making silicosis a significant public health issue. Occupational exposure to crystalline silica must be considered when diagnosing respiratory symptoms to avoid under- or misdiagnosis. The diagnosis of silicosis relies on acknowledging the causal relationship linked to exposure, the pulmonary radiological changes and the exclusion of other diseases with imaging or clinical characteristics similar to silicosis. The diagnosis is often not straightforward and, in many cases, histopathological examination is necessary for confirmation. In this case report, we present two cases in which an initial misdiagnosis led to inadequate treatment.

Long-term follow-up of young denim sandblasters in Turkey.

BACKGROUND: Denim sandblasting-induced silicosis is a recently identified occupational disease. AIMS: In this study, we aimed to evaluate pulmonary and radiological changes in the long-term follow-up of former denim sandblasters. METHODS: Ninety former denim sandblasters were followed from 2007 to 2018. Chest X-rays were evaluated according to the International Labour Organization (ILO) classification. Baseline and final data were compared. Silicosis prevalence, radiological progression and pulmonary dysfunction were evaluated. RESULTS: All of the sandblasters were men. Their mean age was 34 ± 5 years, mean follow-up time was 9 ± 2 years (mean time since initial exposure: 17 ± 2 years) and mean duration of exposure was 34 ± 25 months. Rates of radiological progression and decline in pulmonary during follow-up were 63% and 39%, respectively. During follow-up, all patients were diagnosed with silicosis. All workers who were ILO category 0 at baseline (n = 26, 29%) progressed to higher categories. The number of patients in Category 2 doubled and the number of patients in Category 3 increased by 2.5-fold. Eleven patients developed new large opacities and the number of patients with category C opacity increased from 4 to 13. Exposure time was an independent determinant of radiological progression (OR: 1.0, P = 0.036) and decline in pulmonary function (OR: 1.3, P = 0.019). CONCLUSIONS: The prevalence of silicosis in denim sandblasters increases steadily even after exposure is discontinued. Radiological progression was observed in a higher proportion of workers than a decline in lung function. Duration of exposure was the major determinant of disease progression in our study.