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

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 overdiagnosed, 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 oflow 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 (< 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 (> 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 ofheavy 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.

Cigarette smoking: a risk factor for idiopathic pulmonary fibrosis.

“…Wood dust exposure was reported to be significantly associated with the development of IPF in one of these case-control studies (8). It has also been suggested that unrecognized exposure to ultramicroscopic asbestos fibers may have a role in some cases (9). Other potential etiologic factors suggested by researchers include chronic exposure to domestic wood burning (10), atopy (11), and viral infections (12).…”

Epidemiology of Idiopathic Pulmonary Fibrosis

“…17,34,39 It is important to recognize that effective treatment will probably benefit only a minority of patients and that identification of risk factors is therefore an important priority. Despite the limitations of the studies, the case series [50][51][52][53][54] and a recent casecontrol study 40 suggest that IPF may result from environmental exposures that have not previously been identified. If relevant exposures and markers of individual susceptibility can be identified through epidemiologic investigations, then efforts to prevent IPF will be feasible.…”

“…49 Other evidence of a possible association between environmental exposures and IPF have come from mineralogic microanalysis of lung tissue of patients with IPF. [50][51][52][53][54] In a group of 93 patients with DIP Abraham and Hertzberg 51 found a history of exposure to dust or fumes in 75% of the cases, and with scanning electron microscopy and energy dispersive x-ray analysis found a specific particulate in 92% of these cases. Using the same methods, Monso and associates 53 examined lung tissue from 25 patients with IPF, of which 88% had a pathologic pattern of UIP.…”

Asbestosis and environmental causes of usual interstitial pneumonia

“…Lung mineralogic analyses documenting exposure can impact individual patient care and from an epidemiologic perspective provide further evidence of exposure disease relationships [18–20,50] From a direct clinical care perspective, demonstration of asbestos bodies in lung tissue can be quite helpful (Fig. 3).…”