Clinical, Bronchographic, Radiological And Physiological Observations In Ten Cases Of Asbestosis

Our plain-English summary of Clinical, Bronchographic, Radiological And Physiological Observations In Ten Cases Of Asbestosis, by G.L. Leathart (1960).

The study

• Author: G.L. Leathart
• Published: British Journal Of Industrial Medicine 17(3):213-227, July (1960)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002719. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1960 paper described 10 people with asbestosis (eight men, two women) who were referred to the Nuffield Department of Industrial Health, King's College, University of Durham, and followed for up to eight years. All study subjects had been exposed to both chrysotile and amosite. The patients were compared with 11 laggers (insulators) whose chest X-rays were normal. Bronchography showed bronchiectasis (widened airways) in six of the 10 patients. Clubbing of the fingers and crackling lung sounds were found only in the patients, and the author linked clubbing and coarse crackles mainly to bronchiectasis. Nine patients got clinically worse, while the X-ray stage changed in only two. Compared with the laggers, the patients had stiffer lungs, lower vital capacity and lower diffusing capacity. The author found no convincing evidence of lung fibrosis in the laggers with normal X-rays and said a larger study was needed. The author concluded that low lung compliance was not diagnostic, but had confirmatory value when there was a history of exposure to asbestos dust. The author also suggested measuring exposed workers' vital capacity at regular intervals.

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: Case series of 10 patients with asbestosis, followed over time, with clinical, bronchographic, radiological and lung function findings compared against a control group of 11 asbestos workers with normal radiographs
• Who was studied: 10 patients with asbestosis (eight male, two female, aged 45-65), referred to the Nuffield Department of Industrial Health, King's College, University of Durham, because of respiratory symptoms or an abnormality found on mass radiography; controls were 11 laggers (aged 35-64) whose radiographs three observers judged normal
• Exposure: Chrysotile and amosite fibres, through work such as pipe and boiler covering (lagging) in ships, factories and power stations, and work in an asbestos factory
• Main results:
  • Bronchography showed cylindrical bronchiectasis in six of the 10 patients, with saccular bronchiectasis also present in three of them
  • Clubbing of the fingers and crepitations (crackling lung sounds) were found only in the patients with asbestosis, not in the radiologically normal laggers
  • Among the 10 patients, clubbing and widespread coarse crepitations usually accompanied bronchiectasis and were seldom seen without it; the author noted the numbers were very small
  • The clinical condition got worse in nine of the 10 patients, while the radiological stage changed in only two
  • Five of the patients got worse despite having been removed from contact with asbestos dust
  • In the patients with asbestosis, mean dynamic lung compliance was 0.046 litres per cm of water. The author stated this was less than one fifth of the normal mean and about half the lower limit of normal (0.091).
  • In the laggers without radiological abnormality, mean compliance was 0.189 litres per cm of water. The difference from the patients was highly significant (p less than 0.001).
  • Mean vital capacity was 1.80 litres in the patients with asbestosis (printed as 180 in the scanned text) and 3.20 litres in the laggers without radiological asbestosis. The author reported this difference as statistically significant.
  • Mean diffusing capacity for carbon monoxide at rest was 7.4 in the 10 patients and 13.2 ml/min/mmHg in 10 of the 11 controls. The author reported the difference as significant.
  • Mean dead-space effect was 56.3% in the patients with asbestosis and 39.4% in the controls; the author described the patients' figure as abnormal
  • Maximum voluntary ventilation was lower in the patients than in the controls, who were younger on average; the author called the difference significant
  • The patients showed increased resistance to movement in the lung, measured as non-elastic work of breathing
  • Low pulmonary compliance was not regarded as diagnostic of asbestosis, but as having confirmatory value when there is a history of asbestos exposure
  • The study did not produce convincing evidence that lung fibrosis occurs in asbestos workers before changes appear on the radiograph. One control was considered a definite possibility of undiagnosed asbestosis.
• The authors' conclusion: The author concluded that a low vital capacity accompanies lung fibrosis in asbestos workers, and suggested that exposed workers' vital capacity be measured at regular intervals, with a progressive decline taken as a warning
• Limitations the authors state:
  • The numbers were very small for generalization
  • In four patients bronchography covered only one lung, so the absence of bronchiectasis in two cases was not firmly established, and its extent in the other six was not fully explored
  • Because the patients had been referred to hospital, the results probably reflect fairly advanced disease
  • The study could not assign different roles to different types of asbestos
  • A larger number of asbestos workers would need to be studied before any firm conclusion about changes before radiographic abnormality
  • The tests were done at rest, although breathlessness in asbestosis occurs on exertion

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, Amosite, Insulator, Chest X-Ray, Clubbing, Diffusing Capacity (DLCO), Fibrosis.

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