Table of Contents
Definition of Pneumoconiosis
Pneumoconiosis is the collective term for pulmonary conditions that result from occupational exposure to dust and fiber irritants. The conditions result in the same end-stage disease, pulmonary fibrosis, though follow different patterns of progression, depending on the substance and exposure patterns.
The primary forms of pneumoconiosis that occur in the United States are
- ANTHRACOSIS, also called coal worker’s pneumoconiosis (CWP) and black lung disease, which results from inhalation of coal dust
- ASBESTOSIS, which results from inhalation of asbestos fibers and dust
- BERYLLIOSIS, which results from inhalation of beryllium dust
- BYSSINOSIS, also called brown lung and cotton bract disease, which results from inhalation of raw cotton fibers and dust
- SILICOSIS, which results from inhalation of silica dust
U.S. occupational health experts and federal agencies began tracking and reporting deaths due to pneumoconiosis in 1968, as data related to occupational health. The federal Coal Mine Health and Safety Act of 1969, which established levels of dust exposure standards, was the first substantial effort in the United States to reduce such deaths. The Black Lung Act of 1972 further acknowledged the significant occupational health problems of coal workers, expanding the regulatory scope of the 1969 legislation and establishing a program of government-funded health care for coal workers who developed anthracosis (called black lung disease in the legislation and regulations).
Federal regulation controls occupational exposure to other sources of pneumoconiosis, notably silica, as well. Health experts attribute the declining numbers of diagnoses and deaths in all pneumoconioses, except asbestosis, largely to such controls. The number of people diagnosed with and who die from asbestosis continues to climb, however, because the time between exposure and illness is a minimum of 20 years. Regulatory changes will benefit workers who began working in affected occupations in the last decades of the 20th century, though health experts anticipate that asbestosis will keep rising among those whose work history predates regulations as their average age increases.
Peak exposure to asbestos in the United States occurred in 1975, according to the U.S. Centers for Disease Control and Prevention (CDC), so health experts expect asbestos-exposure related illness to peak between 2015 and 2020. However, asbestos exposure in general dropped significantly after the late 1970s when federal legislation restricted the use of asbestos in materials such as building insulation, ceiling tiles, and flooring.
The other key factor contributing to diminishing disease and death rates for pneumoconiosis is the declining numbers of people working in occupations where exposure is a hazard. The number of coal miners in the United States dropped by half between the 1980s and the 1990s, for example, as more mining functions have become automated or mechanized. Automation continues to reduce hazardous occupational exposures in most industries.
Symptoms and Diagnostic Path
Dry, nonproductive COUGH and DYSPNEA(shortness of breath), particularly with exertion, are the key symptoms of most forms of pneumoconiosis. Anthracosis, berylliosis, byssinosis, and silicosis may show symptoms after relatively short periods of exposure and often improves when exposure ceases. Asbestosis may develop after relatively short exposure though symptoms typically do not become apparent for decades after exposure. The diagnostic path focuses on occupational history and exposure patterns. Diagnostic examination typically includes AUSCULTATION, chest X-RAY, pulmonary function tests, and imaging procedures such as ULTRASOUND, COMPUTED TOMOGRAPHY (CT) SCAN, or MAGNETIC RESONANCE IMAGING (MRI). The pulmonologist may also perform BRONCHOSCOPY, BRONCHOALVEOLAR LAVAGE, or lung biopsy to rule out other causes of symptoms.
|FORMS OF PNEUMOCONIOSIS|
|Form of Pneumoconiosis||Causative Substance||Occupational Exposure|
|anthracosis||coal dust||coal mining|
|asbestosis||asbestos fibers and dust||insulation, aerospace components, brake lining, shipbuilding|
|berylliosis||beryllium dust||electronics, aerospace manufacturing, metal working, metal reclamation processing|
|byssinosis||raw cotton fibers and dust||raw cotton processing, textile production|
|silicosis||silica dust||sandblasting, sand and gravel mining|
Treatment Options and Outlook
The first and most important element of treatment is to end the exposure. Nearly all forms of pneumoconiosis improve with this measure. Permanent damage to the lungs that has already occurred, such as fibrosis, does not reverse though its progression may stop. The disease process of asbestosis is such that damage continues long after exposure ceases. The outlook depends on the form of pneumoconiosis, the length or extent of exposure, and whether the person also smokes. Cigarette smoking significantly worsens both the disease process and the outlook.
Risk Factors and Preventive Measures
Occupational pneumoconiosis develops with exposure to substances that enter and remain in the lungs. Avoiding such exposure is the only certain means of prevention. Workplace measures to reduce exposure to the lowest possible levels include environmental controls to filter or otherwise contain dusts and fibers. Personal protective equipment may include clothing, masks, and respirators.