pulmonary disorders
Silicosis
Diagnosis of Silicosis
Occupational history of silica exposure Chest CT or x-ray Adjunctive tests for distinguishing silicosis from other disorders Diagnosis of silicosis begins with a history of exposure, particularly in specific occupations, including mining, quarry work, stone cutting, construction work, sand blasting, glass making, foundry work, gemstone cutting, and ceramic work and pottery ( Diagnosis references ). It is important to determine the duration of exposure, safety measures in place in the work environment, and the time course for development of symptoms. Despite the fact that crystalline silica is ubiquitous in the environment and increased exposure can occur in a variety of manufacturing settings, silicosis remains underdiagnosed, thus emphasizing the need for a careful and detailed history, Silicosis is usually recognized on the basis of chest x-ray or CT appearance in patients with a history of silica exposure. Chest CT is more sensitive than chest x-ray for detecting silicosis and monitoring for disease progression. For chest x-rays, severity is graded on a standardized scale developed by the International Labor Organization (International Classification of Radiographs of Pneumoconioses). Chronic silicosisis categorized on chest imaging as simple or complicated. In patients with simple silicosis, there is upper lobe predominance of bilateral 1- to 3-mm reticulonodular opacities. Calcified hilar and mediastinal lymph nodes are common and occasionally resemble eggshells; however, eggshell calcification is not pathognomonic for silicosis. Pleural thickening is uncommon unless a severe parenchymal disease abuts the pleura. On chest imaging, a number of disorders can resemble chronic silicosis. They include Sarcoidosis , Complicated silicosisis characterized by large opacities on chest x-ray or conglomerate opacities with calcifications on chest CT. Imaging shows coalescing of nodules when simple silicosis progresses to complicated silicosis. Accelerated silicosisresembles chronic silicosis on chest imaging but develops more rapidly. In acute silicosis,chest CT findings include diffuse alveolar bibasilar opacities in a pattern that mimics pulmonary alveolar proteinosis. Acute silicosis can also be mistakenly characterized as an acute infection. Image courtesy of David W. Cugell, MD. Close up view of upper lung field in simple silicosis. Image courtesy of David W. Cugell, MD. Image courtesy of David W. Cugell, MD. Image courtesy of David W. Cugell, MD. Results of Overview of Tests of Pulmonary Function and measures of gas exchange are variable, depending on the disease stage, and can be normal or show obstructive, restrictive, or mixed abnormalities. In progressive massive fibrosis, pulmonary function tests demonstrate decreased lung volumes, decreased diffusing capacity for carbon monoxide (DLCO), and airway obstruction. Arterial blood gas measurements show hypoxemia. Autoimmune serology, such as antinuclear antibodies and elevated rheumatoid factor, is used in evaluation of a coexisting systemic rheumatic disorder (eg, systemic sclerosis, rheumatoid arthritis). Sputum culture and cytology and bronchoscopy may be indicated when there is suspicion for tuberculosis, cancer, or other interstitial lung diseases such as sarcoidosis. 1.Fazio JC, Gandhi SA, Flattery J, et al. Silicosis Among Immigrant Engineered Stone (Quartz) Countertop Fabrication Workers in California.JAMA Intern Med2023;183(9):991-998. doi:10.1001/jamainternmed.2023.3295 2.Hua JT, Rose CS, Redlich CA. Engineered Stone-Associated Silicosis-A Lethal Variant of an Ancient Disease.JAMA Intern Med2023;183(9):908-910. doi:10.1001/jamainternmed.2023.3260 