Diagnostic Challenges of Mixed Dust Silicosis (Mixed Dust Pneumoconiosis) - 5 Case Reports

Exposure to granular or fibrous inorganic dusts of the alveolar dust fraction initiates inflammatory and fibrotic lung processes. Furthermore, such exposures are associated with an increased risk for lung cancer. By taking a detailed occupational history into consideration the diagnosis of relatively frequent pneumoconioses such as silicosis or asbestosis with dominating pictures, i.e. with its predominant rounded or irregular opacities located especially in the upper and lower lung fields, respectively, is mostly not difficult. However, rarely exposure to a single agent exists. Rather, mixed dust exposures occurring at the same time or in the follow-up have to be taken into consideration, e.g. quartz and carbon in hard coalmines, quartz, asbestos, various other components of cement and concrete dusts in the construction industry. It is also important that during the working life, changes of working processes and used raw materials as well as changes of jobs are associated with variations of type and intensity of exposures. This heterogenicity of exposures and of the associated intrapulmonary depositions result in variations of the pulmonary structural changes, i.e. more or less modifications of the pictures of pneumoconioses as described being typical in textbooks. This is associated with diagnostic difficulties, especially with regard to the differential diagnosis of idiopathic interstitial lung diseases. There is also evidence for genetic influence on disease susceptibility and on the degree of pathohistological changes. This publication includes 5 case reports; all of them were initially diagnosed as idiopathic pulmonary fibrosis, but a detailed workup of the author, mostly during social court litigations, showed that mixed dust pneumoconioses were the most likely diagnoses.