Causes and management of pleural fibrosis.

The development of pleural fibrosis follows severe pleural space inflammation which is typically associated with an exudative pleural effusion. The response of the mesothelial cell to injury and its ability, along with the basement membrane, to maintain its integrity, is vital in determining whether there is normal healing or pleural fibrosis. The formation of a fibrinous intrapleural matrix is critical to the development of pleural fibrosis. This matrix is the result of disordered fibrin turnover, whereby fibrin formation is up-regulated and fibrin dissolution is down-regulated. Cytokines, such as TGF-beta and TNF-alpha, facilitate the fibrin matrix formation. A complete understanding of the pathogenesis of pleural fibrosis and why abnormal pleural space remodeling occurs in some and not in others, remains unknown. Clinically significant pleural fibrosis requires involvement of the visceral pleura. Isolated parietal pleural fibrosis, as with asbestos pleural plaques, does not cause restriction or respiratory impairment. The causes of visceral pleural fibrosis include asbestos-associated diffuse pleural thickening, coronary bypass graft surgery, pleural infection (including tuberculous pleurisy), drug-induced pleuritis, rheumatoid pleurisy, uraemic pleurisy, and haemothorax. Systemic and intrapleural corticosteroids administered during the initial presentation of rheumatoid pleurisy in small series may decrease the incidence of pleural fibrosis. Several randomised control trials using corticosteroids in tuberculous pleurisy have not shown efficacy in reducing residual pleural fibrosis. Decortication is effective in treating symptomatic patients regardless of the cause of pleural fibrosis as long as chronicity has been documented and significant underlying parenchymal disease has been excluded.