Asbestos-related diseases. Algorithm for forensic pathological diagnosis

Our plain-English summary of Asbestos-related diseases. Algorithm for forensic pathological diagnosis, by T. Ehrenreich, T. Espinosa, A.M. Langer, et al (The American Journal of Forensic Medicine and Pathology, 1982).

The study

• Authors: T. Ehrenreich, T. Espinosa, A.M. Langer, A.N. Rohl, S.M. Daum
• Journal: The American Journal of Forensic Medicine and Pathology
• Published: 1982;3(4):315-21
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001754).

Abstract

The pathological diagnosis and proof of asbestos causation in environmental-occupational diseases is based on a spectrum of increasingly sophisticated determinations with greater confidence in detection of asbestos bodies and fibers. These include the following: pathology (histology) and/or thick smears of lung, microincineration, bulk chemical digestion, and electron beam instruments. The requisites of medical and forensic asbestos causation differ, and do not always require the full range of these analytical techniques. The need and significance of some of these determinations, as expressed in number of asbestos bodies and fibers, may be related in many cases to the evidence of asbestosis; to the gross and microscopic pathological findings (asbestosis, lung carcinoma, mesothelioma); the exposure history (type, duration, intensity, and period of latency); and nature of the asbestos mineral. An algorithm for the forensic pathological diagnosis of asbestosis and of asbestos-related diseases is proposed.

In plain English

This 1982 article reported no new patient data. The authors described laboratory methods for finding asbestos bodies (coated fibers) and uncoated asbestos fibers in lung tissue. They also proposed a step-by-step procedure, or algorithm, for the forensic pathological diagnosis of asbestosis and asbestos-related diseases. The methods, in order of increasing sophistication, were histology and thick smears of lung, microincineration (ashing), bulk chemical digestion, and electron-beam instruments. The authors wrote that if light microscopy finds asbestos in a person with a history of asbestos exposure, and all the circumstances are favorable, one may state that the fibers are asbestos "with reasonable medical certainty." With a verified exposure history, they wrote, electron-beam instruments are usually not required. They wrote that firm identification with these instruments combines fiber shape, crystal structure and chemistry, and that chemical analysis alone is not sufficient. They concluded that the procedure rests on an accurate history of substantial exposure with a reasonable latent period, or relevant clinical disease, and on adequate tissue samples. They noted that light microscopy cannot identify uncoated fibers with absolute certainty.

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: Methods and proposal article (no original patient data). It describes laboratory techniques for detecting asbestos in lung tissue and proposes an algorithm for forensic diagnosis.
• Who was studied: No study population. The article describes examination of lung tissue (and hilar lymph nodes) in cases suspected of asbestos-related disease. It comes from the Environmental Sciences Laboratory, Mount Sinai School of Medicine, and Downstate Medical Center, New York.
• Exposure: Asbestos exposure in general, occupational and nonoccupational. The fiber types named in the discussion of electron microscopy identification are chrysotile and the amphiboles crocidolite, amosite, tremolite and anthophyllite.
• Main results:
  • The authors described four groups of techniques for lung tissue: histology (including thick smears), microincineration, bulk chemical digestion, and electron-beam instruments. The last group covers transmission and scanning electron microscopy with electron diffraction and microchemical analysis.
  • The authors wrote that if asbestos is found by a light microscopy method in a person with a history of asbestos exposure, and all the circumstances are favorable, one may state that the fibers are asbestos with reasonable medical certainty.
  • The authors stated that with a verified history of asbestos exposure, there is no need for techniques that give absolute proof the particles are asbestos or that identify the asbestos type. In practice, this usually means stopping short of electron-beam instruments.
  • The authors wrote that microchemical identification without morphological fiber identification and structure analysis is not sufficient for specific fiber identification, because some nonasbestos minerals have chemistries similar to asbestos varieties.
  • The authors described their laboratory's 175-micron stack method. Blocks of lung from seven sites are cut into 25-micron sections, which are stacked on one slide and ashed. The slide is then examined with bright light for asbestos bodies and with polarized light for uncoated fibers.
  • The authors called bulk chemical digestion one of the simplest, most reliable and reproducible methods. In this method, 0.5 to 5 g of lung tissue is digested in 5.25% sodium hypochlorite or in potassium hydroxide, and the residue is examined on a filter.
  • As a general statement, not a measurement made in this article, the authors wrote that asbestos body counts per gram of lung may range from the hundreds to the thousands in a heavily exposed asbestos worker. They wrote that counts in nonexposed controls are usually less than 20.
  • The authors stated that needle (fiber optic) biopsies are of limited use for fiber analysis, because small tissue samples rarely reflect the total lung particle burden. They wrote that larger amounts (1 to 4 g) give more representative results.
  • The authors described the common legal standard of proof as a "reasonable degree of medical certainty" or "more likely than not." They equated this with a 51% chance of a causal relationship.
• The authors' conclusion: The authors proposed a stepwise algorithm. It begins with the exposure history and adequate tissue, then moves through increasingly sophisticated methods until enough asbestos bodies or fibers are found. They emphasized that the entire procedure depends on two things. The first is an accurate history of substantial exposure with a reasonable latent period, or clinical disease known to be associated with asbestos. The second is adequate and appropriate tissue samples.
• Limitations the authors state:
  • Uncoated fibers seen with polarized light cannot be identified with absolute certainty, and submicroscopic fibers cannot be seen with the light microscope.
  • The authors noted that a higher tissue concentration in exposed than in nonexposed people may not hold for some chrysotile exposure, because chrysotile can slowly dissolve in tissue fluids.
  • The authors stated that the degree of lung fibrosis is not necessarily related to the number and concentration of asbestos fibers, and that individual variation in response is great.

Topics

Medical terms in this study, explained in our Lexicon: Causation, Occupational Disease, Asbestos Bodies, Pathology, Histology, Carcinoma, Mesothelioma, Exposure History.

Related studies

• Forensic detection and investigation of occupational-environmental disease — T. Ehrenreich, I.J. Selikoff (1980)
• Diseases associated with asbestos exposure. Diagnostic perspectives in forensic pathology — T. Ehrenreich, I.J. Selikoff (1983)
• Comparison of the ultra-low-dose Veo algorithm with the gold standard filtered back projection for detecting pulmonary asbestos-related conditions: a clinical observational study — M. Tekath, F. Dutheil, et al. (2014)
• Diagnosis and initial management of nonmalignant diseases related to asbestos — American Thoracic Society (2004)
• Fiber counting and analysis in the diagnosis of asbestos-related disease — A. Churg (1982)
• Conventional and high resolution computed tomography in the diagnosis of asbestos-related diseases — D.A. Lynch, G. Gamsu, et al. (1989)

Browse more research in The American Journal of Forensic Medicine and Pathology, or return to medical research.