Causes and management of pleural fibrosis

Our plain-English summary of Causes and management of pleural fibrosis, by J.T. Huggins, S.A. Sahn (Respirology, 2004).

The study

• Authors: J.T. Huggins, S.A. Sahn
• Journal: Respirology
• Published: 2004;9(4):441-7
• Type of article: Review
• Cited by: 79 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

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.

In plain English

This article was an invited review, not a new study. The authors reviewed published research on how pleural fibrosis (scarring of the lining around the lungs) develops, what causes it, and how it is treated. Causes covered included asbestos, tuberculous and rheumatoid pleurisy, and coronary bypass surgery. For asbestos, the review described two forms. Pleural plaques affect the parietal (chest-wall) pleura, appear on average 20 to 30 years after first exposure, and are not typically associated with respiratory symptoms. Diffuse pleural thickening mainly involves the visceral pleura covering the lung, and restricted breathing and breathlessness can occur. Citing earlier studies, the review reported diffuse pleural thickening in 5 to 14% of asbestos-exposed individuals. Its table listed plaques as common (up to 58%). It stated that most authors agree surgery to remove the scar layer (decortication) can succeed in progressive diffuse pleural fibrosis when significant lung scarring is absent. The authors concluded that clinically significant pleural fibrosis requires visceral pleural involvement. They also concluded that people with isolated parietal fibrosis, such as asbestos-induced plaques, do not develop respiratory symptoms.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Invited narrative review
• Who was studied: No study population of its own. The review covered published literature on causes of pleural fibrosis, including asbestos-associated diffuse pleural thickening, coronary bypass surgery, pleural infection including tuberculous pleurisy, drug-induced pleuritis, rheumatoid pleurisy, uraemic pleurisy and haemothorax.
• Exposure: Asbestos exposure in general (no specific fiber types named), among other causes of pleural fibrosis. The review stated that asbestos-related pleural fibrosis depends on the duration and cumulative dose of exposure.
• Main results:
  • The review described pleural plaques as lying on the parietal pleura and stated they are not typically associated with respiratory symptoms.
  • The review stated that pleural plaques appear on average 20 to 30 years after initial exposure to asbestos.
  • The review stated that diffuse pleural thickening primarily involves the visceral pleura.
  • In the review's table, restrictive physiology and dyspnoea (breathlessness) were listed as possible with diffuse pleural thickening.
  • Citing earlier studies, the review reported diffuse pleural thickening in 5 to 14% of asbestos-exposed individuals.
  • The review's table listed pleural plaques as common (up to 58%).
  • Citing an earlier report of 185 cases of asbestos-associated diffuse pleural thickening (McLoud and colleagues), the review stated that extension of lung fibrosis into the pleural space was infrequent (10% of cases).
  • The review stated that most authors agree decortication can succeed in progressive, diffuse pleural fibrosis when clinically significant lung (parenchymal) fibrosis is not present.
  • For tuberculous pleurisy, the review cited a Cochrane review (Matchaba and Volmink) that found insufficient evidence for corticosteroids to prevent pleural fibrosis.
  • For rheumatoid pleurisy, the review stated there are no controlled studies of corticosteroids.
• The authors' conclusion: The authors concluded that clinically significant pleural fibrosis requires involvement of the visceral pleura. They concluded that patients with isolated parietal pleural fibrosis, such as asbestos-induced pleural plaques, do not develop respiratory symptoms.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Fibrosis, Inflammation, Pleural Effusion, Mesothelial Cells, Cytokine, Visceral Pleura, Pleural Plaques, Diffuse Pleural Thickening.

Related studies

• Do asbestos-related pleural plaques on HRCT scans cause restrictive impairment in the absence of pulmonary fibrosis? — B. Clin, C. Paris, et al. (2011)
• Asbestos-induced pleural fibrosis and impaired lung function — D.A. Schwartz, L.J. Fuortes, et al. (1990)
• Pathogenesis of pleural fibrosis — S.E. Mutsaers, C.M. Prele, et al. (2004)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• Splicing factor SRSF6 mediates pleural fibrosis — L.M. Liang, L. Xiong, et al. (2021)
• Chronic pleuritic pain in four patients with asbestos induced pleural fibrosis — A. Miller (1990)

Browse more research in Respirology, or return to medical research.