|
What is involved? (including coding of cases) SABRE Case Studies and Information
|
2. Diffuse Pleural ThickeningDiffuse pleural thickening of the pleura is less specific to asbestos exposure than for pleural plaque development. Thickening and fibrosis of the visceral pleura occurs with fusion to the parietal pleura over a wide area. Diffuse pleural thickening may result from exudative pleural effusions secondary to asbestos exposure, but other causes of pleural disease may also cause thickening (e.g. haemothorax, connective tissue diseases, tuberculosis, chest surgery, drugs such as methysergide and parapneumonic effusions). Diffuse pleural thickening on a chest radiograph presents as a smooth non-interrupted pleural density extending for at least 25% of the lateral chest wall, with or without blunting of the costophrenic angle (McLoud et al., 1985). It has also been defined on CT scanning as a continuous sheet more than 5 cm wide, more than 8 cm in craniocaudal extent, and more than 3 mm thick (Lynch et al., 1989). Diffuse pleural thickening may be difficult to differentiate from multiple pleural plaques, but the following may assist (Fletcher., 1970):
CT is more sensitive and specific for the detection of diffuse pleural thickening than chest radiography. Diffuse pleural thickening may result in impaired lung function in the absence of parenchymal fibrosis, producing a restrictive ventilatory defect with a decrease in lung volumes and preserved gas transfer. With severe pleural restriction, the KCO may be increased (Al Jarad et al., 1991, Yates et al., 1996). References
|