Diagnostic criteria of pneumoconiosis

Abstract

Asbestosis, silicosis and CBD are the most common pneumoconiosis. Being characterized by the presence of interstitial pulmonary fibrosis, a relevant issue is represented by the differential diagnosis with non-occupational interstitial pulmonary diseases. Epidemiological data are scarce due to the lack of standardized diagnostic criteria, varied physician awareness and training, the limitations of the available data sources (death certificates, hospital records, medical surveillance, notification to the public insurance system) and the long latency period between exposure and onset of the disease. Diagnosis of pneumoconiosis requires the recognition of occupational exposure, the existence of an adequate latency period, the exclusion of extraprofessional causal factors, and the presence of compatible clinical, radiological and functional respiratory aspects. The CT scan performed with high-resolution technique (High Resolution Computed Tomography HRCT) allows to confirm radiological signs of pneumoconiosis highlighting the early stages that cannot be diagnosed with the standard chest radiography. Indeed, this technique is much more sensitive than standard Rx even if it is difficult to determine in which extent, given the variability of data reported in the literature. The main limitation of this method is the huge variability intra and inter-operator. Therefore, in the last ten years several groups have tried to create an interpretation model for the classification of pneumoconiosis. ICOERD is a classification scheme for digital HRCT built on a model similar to the ILO classification for the standard chest radiogram. It consists of several elements for classification: small opacity with regular or irregular shape/linear to DIAGNOSTIC CRITERIA OF PNEUMOCONIOSIS www.preventionandresearch.com Oct-Dec 2013|P&R Scientific|Volume 3|N°4 310 which must also be defined the location and the profusion, large opacities, ground glass, honeycombing and emphysema. Pathological diagnosis of asbestosis is placed in the presence of a diffuse pulmonary fibrosis with a particular pattern of asbestos bodies and/or fibers attesting a relevant exposure. In asbestosis the interstitial fibrosis is located in the basilar and subpleural regions as in idiopathic pulmonary fibrosis (IPF) which is the main differential diagnosis. In addition to the presence of asbestos bodies and fibers, histologically asbestosis differs from IPF in the poor inflammatory component and the lesser presence of fibroblastic foci. The very early stages, characterized by bronchiolitis, pose a difficult diagnostic problem because lesions are very similar to those smoked-related. In any case, peribronchiolar fibrosis does not represent asbestosis. The most common form of silicosis (chronic simple silicosis) occurs after a latency period of at least 10 years and can be as long as 40 years. A more rapid onset is caused by intense exposure: the clinical appearance is similar, but the latency is shorter (5-10 years). In asbestosis and silicosis the most important factor in determining fibrosis is the cumulative dose. The CBD is a granulomatous disease similar to sarcoidosis, caused by cell-mediated sensitization to the metal. The management of cases of pneunoconiosis does not differ from that of other pulmonary fibrosis if not for two things: the removal from exposure and the need of primary and secondary prevention in exposed co-workers.