Apical pleural scarring is the result of a thickening of the membrane that covers the lungs, according to Radiopaedia.org. The causes of this thickening include asbestos exposure, a secondary infection due to pulmonary tuberculosis and radiation-induced pulmonary fibrosis. There is no known cure for this condition, and apical pleural thickening and scarring reduces lung capacity, according to Pleural Thickening.
Apical pleural thickening and scarring usually occurs secondarily after an initial infection. Radiopaedia.org reveals that radiation fibrosis occurs after treatment for other lung diseases. Scarring also happens after prolonged exposure to asbestos, according to the Mesothelioma Center, which also indicates that pleural scarring is one of the most common signs of exposure when asbestos fibers implant in the lungs.
When the scar tissue increases, the lungs become encased, and the space between the pleura and inner part of the lungs becomes closed off. Apical pleural scarring causes chest pain and a decline in breathing function, according to the Mesothelioma Center.
Asbestos is not the only cause of apical pleural thickening and scarring. Empyema is an accumulation of pus in the pleura. Hemothorax takes place when too much blood is in the pleural space, and fibrinous pleuritis occurs when the pleura becomes inflamed. The Mesothelioma Center also states that a pulmonary embolism, or blood clot in the lungs, can cause scarring in the apical pleura.