Asbestosis is a disease marked by:
Pathophysiology
1) lung disease caused by chronic exposure to certain silicate particles (chrysolite, amosite, crocidolite) 2) major health problems caused by exposure are pulmonary fibrosis, lung cancers, and mesotheliomas of pleura, peritoneum, and rarely of pericardium
Signs and Symptoms of Asbestosis
1) shortness of breath 2) cough 3) chest pain 4) hemoptysis 5) clubbing of fingers (in mesothelioma)
Characteristic Test Findings
Radiology – 1) pleural plaques (esp. on diaphragm, lower lung surfaces, and cardiac borders 2) pleural effusions (sometimes bilateral) 3) decreased lung volumes 4) “ground glass” appearance as fibrosis progresses PFTs 5) restrictive pattern 6) reduced diffusion capacity
Histology/Gross Pathology
1) phagocytosis of fibers by macrophages with damage to macrophage membrane and release of cytokines that injure adjacent lung parenchyma 2) fibrosis progresses to eventual honeycombing of lung parenchyma 3) asbestos body (ferruginous body) – golden brown, fusiform rods of asbestos with protein and iron
Associated Conditions
1) mesothelioma 2) lung cancers (both squamous cell and adenocarcinoma)
Inheritance/
Epidemiology
1) disease of occupational exposure in shipyard workers, welders, pipe fitters, boilermakers, building tradesmen 2) requires moderate to intense exposure for 5-10 years to develop disease
Treatment
1) palliative chemotherapy (prognosis is poor) 2) photodynamic therapy
Tips for USMLE
1) there is a strong association of mesothelioma with asbestosis 2) the combination of smoking and asbestosis increases the risk for lung cancer rather than mesothelioma 3) presence of pleural plaques implies exposure to asbestos – not neccessarily active disease
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