Lung dust content in idiopathic pulmonary fibrosis: a study with scanning electron microscopy and energy dispersive x ray analysis

Our plain-English summary of Lung dust content in idiopathic pulmonary fibrosis: a study with scanning electron microscopy and energy dispersive x ray analysis, by E. Monsó, J.M. Tura, J. Pujadas, et al (British Journal of Industrial Medicine, 1991).

The study

• Authors: E. Monsó, J.M. Tura, J. Pujadas, F. Morell, J. Ruiz, J. Morera
• Journal: British Journal of Industrial Medicine
• Published: 1991;48(5):327-31
• Cited by: 17 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. 004165).

Abstract

Examination with an optical microscope and polarised light is not sensitive enough to detect low diameter asbestos fibres. This limitation implies that some cases of asbestosis can be erroneously diagnosed as idiopathic pulmonary fibrosis (IPF) if asbestos bodies are not found in the standard examination of abnormal tissue. To determine whether IPF is over-diagnosed, a study was carried out with scanning electron microscopy (SEM) and energy dispersive x ray analysis (EDXA) on 25 samples previously diagnosed as IPF at the standard examination. Scanning electron microscopy will show the presence of low diameter fibres in the lung without tissue destruction, and these fibres can be identified using EDXA. The quantitative and qualitative results for lung tissue from patients diagnosed as having IPF were compared with the results of the examination of 25 samples of normal lung. Most of the samples from patients diagnosed as having IPF showed only occasional inorganic particles (less than 10 particles/SEM field at 160 x), results equivalent to the results obtained in normal lung. Two cases of IPF, however, showed innumerable asbestos fibres (greater than 100 fibres/SEM field). One of these two patients had an antecedent of brief exposure to asbestos. No environmental antecedent was found in the second patient. Asbestosis was the final diagnosis for these two patients. The examination of inorganic particles in normal lungs showed mainly non-fibrous silicates (61.4%) and particles of heavy elements (34.9%). Only one asbestos fibre was found (0.9%). It is concluded that standard pathological techniques overdiagnose IPF in a few cases in which asbestos bodies are not found with the optical microscope.

In plain English

This study, from hospitals in Catalonia, Spain, re-examined lung biopsy tissue from 25 patients who had earlier been diagnosed with idiopathic pulmonary fibrosis (IPF), lung scarring with no known cause, after a standard light microscope examination. The authors used scanning electron microscopy with energy dispersive x ray analysis, which can find and identify very thin fibres. They compared the results with 25 normal lung samples from people who had died, mainly of cardiovascular causes, and had no known dust exposure. One sample from each group was discarded because of poor image quality. Most IPF samples showed fewer than 10 inorganic particles in the area studied, similar to normal lungs. However, 2 of the 24 IPF samples analysed (8.3%) contained more than 100 asbestos fibres. One of these patients had a brief occupational asbestos exposure, and no relevant exposure was found for the other. The authors gave both a final diagnosis of asbestosis. In the normal lungs, 1 of 109 particles found (0.9%) was an asbestos fibre. The authors concluded that standard techniques overdiagnose IPF.

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: Comparative laboratory study: scanning electron microscopy (SEM) and energy dispersive x ray analysis (EDXA) of lung samples previously diagnosed as IPF, compared with normal lung samples
• Who was studied: 25 surgical lung biopsy samples, mainly from the lingula, from patients with a previous pathological diagnosis of IPF (mean age 58.3, SD 13.7). The comparison group was 25 normal lung samples from patients who had died, mainly of cardiovascular causes (mean age 62.8, SD 14.7; 12 men, 13 women), with a history of inhaling inorganic particles excluded. Hospitals in Badalona and Barcelona, Catalonia, Spain.
• Exposure: Inorganic particles in lung tissue, classified as silica, non-fibrous silicates, asbestos (fibrous silicate with Mg or amphibole composition) and heavy elements. Nine IPF patients had exposure histories that might have involved inhaling inorganic particles, including quarry work, cement, chemicals, a rubber factory, asbestos work for three or 20 years, and a husband who was an asbestos worker.
• Main results:
  • One normal lung sample and one IPF sample were discarded because poor SEM image quality prevented recognition of the particles, leaving 24 samples in each group.
  • IPF group: most samples had only occasional inorganic particles (fewer than 10 in the area studied), but two samples (8.3%) showed innumerable asbestos fibres (more than 100 asbestos fibres in the area).
  • Of the two IPF patients with innumerable asbestos fibres, one had a brief occupational exposure to asbestos and no relevant exposure history was found for the other.
  • The authors stated that the final diagnosis for these two cases must be asbestosis.
  • Normal lung group: 18 of 24 samples showed only occasional inorganic particles (fewer than 10).
  • Normal lung group: of 109 particles found, 67 (61.4%) were non-fibrous silicates and 38 (34.9%) were particles of heavy elements.
  • Normal lung group: one asbestos fibre was found among the 109 particles (0.9%), in one sample that contained 27 particles. That person had no relevant inhalation history.
• The authors' conclusion: The authors concluded that standard techniques (optical microscopy with polarised light) overdiagnose IPF. They suggested that more sensitive, non-destructive techniques such as SEM and EDXA could show that some samples previously diagnosed as IPF are really asbestosis.

Topics

Medical terms in this study, explained in our Lexicon: Idiopathic, Pulmonary Fibrosis, Scanning Electron Microscopy (SEM), Asbestos Bodies, Silicate.

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