Symptomatic benign pleural effusions among asbestos insulation workers: residual radiographic abnormalities

Our plain-English summary of Symptomatic benign pleural effusions among asbestos insulation workers: residual radiographic abnormalities, by R. Lilis, Y. Lerman, I.J. Selikoff (British Journal of Industrial Medicine, 1988).

The study

• Authors: R. Lilis, Y. Lerman, I.J. Selikoff
• Journal: British Journal of Industrial Medicine
• Published: 1988;45(7):443-9
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000247).

Abstract

During a cross sectional medical survey of 2815 insulation workers with 30 years or more from onset of asbestos exposure conducted from 1981 to 1983, a positive history of benign pleural effusion was found in 20 (0.71%). Two or three such episodes had occurred in four of these 20 subjects. The chest x ray abnormalities in these cases were characterised by pleural fibrosis in 19 and diffuse pleural fibrosis with blunting of the corresponding costophrenic angle in 16. In the total group of 2815 insulation workers diffuse pleural fibrosis was found in 142 (5.0%). Thus diffuse pleural fibrosis with blunting of the corresponding costophrenic angle is a frequent residual abnormality after benign pleural effusion. Its impact on pulmonary function can be pronounced.

In plain English

This cross-sectional survey examined 2815 asbestos insulation workers from a union cohort in the United States and Canada, each with 30 or more years since first exposure, in 1981 to 1983. The article does not name asbestos fiber types. Twenty workers (0.71%) reported a definite past pleural effusion (fluid around the lung), and four of them had two or more episodes. The time from first exposure to the effusion ranged from one to 62 years and was under 10 years in only four. On chest x-rays, 19 of the 20 had pleural fibrosis. In 16 it was diffuse, with blunting of the costophrenic angle. Only one x-ray was normal. In the whole group of 2815, 142 (5.0%) had diffuse pleural fibrosis. By the authors' estimate, workers with an effusion history were about 16 times as likely to show it. The authors concluded that diffuse pleural thickening with a blunted costophrenic angle is the most frequent residual x-ray abnormality after benign pleural effusion. They noted that including only remembered, symptomatic cases probably underestimated how often effusions occurred.

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: cross-sectional medical survey (medical history, examination and chest x-rays) within an established cohort
• Who was studied: 2815 asbestos insulation workers from a union cohort established in 1967, each with 30 or more years since onset of asbestos exposure, examined 1981-3 (5377 eligible cohort members were invited)
• Exposure: occupational asbestos exposure as insulation workers (union members in the United States and Canada); fiber types and doses not given
• Main results:
  • 20 of the 2815 examinees (0.71%) had a history of definite pleural effusion
  • 4 of the 20 workers with effusion had two or more episodes
  • Among the 20, the interval from onset of asbestos exposure to effusion ranged from 1 to 62 years and was shorter than 10 years in only four
  • Among the 20, pleural fibrosis was present in 19, and in 16 it was diffuse with blunting of the corresponding costophrenic angle
  • The chest x-ray was normal in only 1 of the 20
  • Among the 20, diffuse pleural fibrosis was thicker than 1 cm (width C) in seven
  • In the total group of 2815, diffuse pleural fibrosis was found in 142 (5.0%): unilateral in 94 (3.3%) and bilateral in 48 (1.7%)
  • Workers with a history of pleural effusion were about 16 times more likely to show diffuse pleural fibrosis on chest x-ray than the other examined workers
• The authors' conclusion: The authors concluded that diffuse pleural thickening with a blunted costophrenic angle is the most frequent residual radiological abnormality after benign pleural effusion
• Limitations the authors state:
  • Only symptomatic cases (known to the worker and diagnosed by a physician) were included
  • Because benign effusions may go unnoticed, the true frequency may have been higher than the 20 reported cases
  • Recall over periods of 30 or more years probably led to underestimation

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: Pleural Effusion, Insulator, Asbestos Exposure, Fibrosis, Costophrenic angle.

Related studies

• Pleurectomy decortication in the treatment of the "trapped lung" in benign and malignant pleural effusions — S. Rathinam, D.A. Waller (2013)
• Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion — K. Kato, K. Gemba, et al. (2016)
• Relationship of lung geometry to the development of pleural abnormalities in insulation workers exposed to asbestos — R. Delfino, P. Ernst, et al. (1989)
• Radiographic abnormalities in asbestos insulators: effects of duration from onset of exposure and smoking. Relationships of dyspnea with parenchymal and pleural fibrosis — R. Lilis, A. Miller, et al. (1991)
• Asbestosis: interstitial pulmonary fibrosis and pleural fibrosis in a cohort of asbestos insulation workers: influence of cigarette smoking — R. Lilis, I.J. Selikoff, et al. (1986)
• The radiographic pleural abnormalities in asbestos exposure: relationship to physiologic abnormalities — R.N. Jones, T. McLoud, et al. (1988)

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