Study Syllabus for Classification of Radiographs of Pneumoconioses

DRAFT DOCUMENT

This is a draft document meant for review only. Do not cite this document.

Clinical Overview

Major Occupational Lung Diseases

Pneumoconioses

Coal Mine Dust Lung Disease (Part 2)

Small irregular opacities may also be an isolated radiographic finding, most commonly in the lower lungs.4,7,8 While these irregular opacities can be related to smoking, some are due to lung fibrosis, and can be progressive. Indeed, there are reports of a pattern of diffuse interstitial fibrosis characterized by lower lung predominant fibrosis (Fig. 6), with histology similar to usual interstitial pneumonia including peripheral subpleural honeycombing, traction bronchiectasis, and ground glass opacity.9-11 This pattern is known as dust related diffuse fibrosis. Recognizing this pattern is important as it may be associated with lung cancer11 and with rapidly progressive CWP, (defined as progression of ILO classification by greater than one sub-category over five years or less or the development of PMF in miners exposed after 1980 see Antao et. al.).12,13,14 CT is helpful for confirmation and characterization of this pattern of abnormality, and comprehensive clinical evaluation is needed to assess other potentially treatable interstitial lung diseases.

Rapidly progressive CWP has been observed in recent years in the U.S. often in younger Appalachian miners.12-14 Careful comparison with prior radiographs is important to identify this clinically significant entity.

Multiple studies of coal miners show a consistent and dose-dependent relationship between exposure to respirable coal mine dust and chronic airways diseases including emphysema and chronic bronchitis.15 Coal mine dust injures the airways in an additive fashion with tobacco smoking.16 All pathologic types of emphysema are associated with coal mine dust exposure, and the pathological severity of emphysema is proportional to the retained lung dust content.17,18 Lung function abnormalities are typically obstructive. The diffusion capacity may be decreased, and exercise-related ventilatory and gas exchange abnormalities are common.

Medical management of CMDLD consists mainly of supportive care, when appropriate, such as supplemental oxygen, bronchodilators, smoking cessation counseling, recommended vaccinations, weight loss, regular exercise and pulmonary rehabilitation. Early disease recognition to minimize or eliminate ongoing coal mine dust exposure and for appropriate benefits counseling is important. If a careful occupational exposure history is obtained, lung biopsy is rarely needed to confirm chest imaging findings of CWP.

Page last reviewed: November 4, 2019