Clinical features to stage alveolitis in asbestos workers

Our plain-English summary of Clinical features to stage alveolitis in asbestos workers, by R. Bégin, A. Cantin, Y. Berthiaume, et al (American Journal of Industrial Medicine, 1985).

The study

• Authors: R. Bégin, A. Cantin, Y. Berthiaume, R. Boileau, G. Bisson, G. Lamoureux, M. Rola-Pleszczynski, G. Drapeau, S. Massé, M. Boctor
• Journal: American Journal of Industrial Medicine
• Published: 1985;8(6):521-36
• Cited by: 49 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To analyze the clinical features of asbestos-induced alveolitis and stage its activity, we evaluated 217 asbestos workers by the usual clinical, radiological, and functional parameters and computerized gallium 67(Ga) lung scan; we obtained bronchoalveolar lavage (BAL) in 33 and lung biopsy in 6. In addition, we scored the profusion of lung rales and correlated it with other parameters of severity of asbestosis. In the 55 workers without asbestosis and normal 67Ga scan, BAL analyses were comparable to those of controls. Of the 56 without asbestosis but increased 67Ga lung uptake, BAL analyses in 8 documented a predominantly macrophagic alveolitis (confirmed on lung biopsy in 3), with the highest levels of BAL fibronectin. In the 106 workers with asbestosis, 67Ga lung uptake was increased in 75; BAL in 17 demonstrated a macrophagic and neutrophilic alveolitis with elevated fibronectin levels. Lung biopsy in 3 of the latter workers documented peribronchiolar fibrosing alveolitis. Rale scores in all workers or in those without asbestosis did not correlate with 67Ga scores; they correlated fairly well with profusion of parenchymal opacities (Rs = 0.42) and rigidity of the lung pressure-volume curve (Rs = 0.39). Thus, 67Ga lung uptake is an early indicator of chronic macrophagic alveolitis in asbestos workers, which usually progresses to asbestosis. In the disease, profusion of lung rales constitutes a simple clinical mode of assessment of disease severity that correlates better with radiological and functional parameters than with parameters of alveolitis.

In plain English

The authors studied 217 workers exposed only to Canadian chrysotile asbestos in the mines and mills of Quebec's Eastern Townships, for an average of 29 years. All had clinical, chest X-ray and lung function tests and a gallium-67 lung scan, used to detect lung inflammation (alveolitis). Thirty-three also had lung washing (bronchoalveolar lavage), compared with 18 volunteers without occupational exposure at risk for pneumoconiosis, and 6 had lung biopsy. By standard criteria, 106 workers had asbestosis, and gallium uptake was increased in 75 of them. Of 111 workers without asbestosis, 56 had a stiff lung pressure-volume curve, increased gallium uptake, or both. In 8 of these, lavage showed more cells, macrophages, neutrophils and fibronectin than in controls, and biopsies in 3 showed inflammation centered on small airways. In the 17 workers with asbestosis who had lavage, neutrophils were twice those of those 8 workers, and biopsies in 3 workers with asbestosis showed fibrosis. A score of crackling lung sounds (rales) correlated with X-ray opacities (Rs = 0.42) and lung stiffness (Rs = 0.39), but not with gallium uptake. The authors concluded that this early alveolitis had features of a chronic alveolitis.

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: Clinical study of asbestos workers in which all had clinical, radiological, lung function and gallium-67 scan examinations. Subsets also had bronchoalveolar lavage, compared with volunteer controls, and open lung biopsy.
• Who was studied: 217 asbestos workers from the mines and mills of the Eastern Townships of Quebec, Canada, average age 59 (range 40-72). Ninety percent were current or ex-cigarette smokers. Lavage results were compared with 18 volunteers without occupational exposure at risk for pneumoconiosis. The study dates are not given.
• Exposure: Canadian chrysotile asbestos only, in mining and milling, for an average of 29 years (range 7-42). Exposure was heavy during the first 10 years of employment, moderate during the next 10 and lesser in recent years. A cumulative exposure index was built from job records and a 0 to 3 dust estimate.
• Main results:
  • 106 of the 217 workers met the diagnostic criteria for asbestosis (group C). Their lung pressure-volume curve was rigid in all of them, and gallium-67 lung uptake was increased in 75 of the 106.
  • Of the 111 workers without asbestosis, 56 (group B) had a rigid lung pressure-volume curve, increased gallium-67 uptake, or both; 45 had both. The other 55 (group A) had neither.
  • Rales were scored at grade 0.5 or above in 13% of group A, 12% of group B and 86% of group C.
  • The decline in vital capacity over the preceding 3-5 years was 13 plus or minus 12 ml per year in group A, 18 plus or minus 8 in group B and 29 plus or minus 5 in group C (p less than 0.02 for group C vs A and/or B only).
  • Of the 33 workers who had lavage, 8 were in group A, 8 in group B and 17 in group C.
  • In lavage, group A (8 workers) differed from the 18 controls only in higher lymphocyte and neutrophil counts (p less than 0.05).
  • Group B lavage (8 workers) differed from group A and controls: total cells about 2-fold, macrophages 2-3-fold and neutrophils 5-10-fold.
  • Group C lavage (17 workers) had twice the neutrophils of group B, which was 10-20-fold those of controls or group A.
  • Lavage fibronectin was highest in group B (2-4-fold group A and controls). It was lower in group C but still significantly higher than in controls and group A combined. A table footnote states there was no significant difference between groups B and C.
  • Of the six workers who had open lung biopsy, three were in group B and three in group C.
  • On lung biopsy, the 3 group B workers had focal lesions centered around small airways, with macrophage accumulation.
  • On lung biopsy, the 3 group C workers also had diffuse peribronchiolar fibrosis extending to the lung interstitium.
  • In all 217 workers, rale scores correlated best with parenchymal opacity score (Rs = 0.42, p less than 0.01), rigidity of the lung pressure-volume curve (Rs = 0.39, p less than 0.01) and diffusion capacity (Rs = 0.33, p less than 0.01).
  • Rale scores showed no significant correlation with gallium-67 lung uptake or with lavage cell or biochemical findings.
  • Serum angiotensin-converting enzyme showed no significant changes in early or late stages of asbestosis.
• The authors' conclusion: The authors concluded that the early macrophagic alveolitis in asbestos workers, detected by the lung pressure-volume curve and gallium-67 scan, has some of the fundamental lavage features of a chronic alveolitis.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Biopsy.

Related studies

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• Bronchoalveolar lavage in pulmonary fibrosis: comparison of cells obtained with lung biopsy and clinical features — P.L. Haslam, C.W. Turton, et al. (1980)
• British Thoracic Society study of cryptogenic fibrosing alveolitis: current presentation and initial management. Fibrosing Alveolitis Subcommittee of the Research Committee of the British Thoracic Society — I.D. Johnston, R.J. Prescott, et al. (1997)
• Desquamative interstitial pneumonitis. Cellular phase of fibrosing alveolitis — R.R. Tubbs, S.P. Benjamin, et al. (1977)
• Asbestosis and other pulmonary fibrosis in asbestos-exposed workers: high-resolution CT features with pathological correlations — H. Arakawa, T. Kishimoto, et al. (2016)
• The clinical relevance of asbestos-induced pleural fibrosis — D.A. Schwartz (1991)

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