Exposure to asbestos (several mesothelioma cases), is not limited to persons who directly handle the material. Cases of asbestos- related diseases have been encountered in individuals with moderate exposure, such as the painter or electrician who works alongside the insulation worker in a shipyard or the housewife who does no more than shake out and wash her husband’s work clothes. Community exposure has probably resulted from the use of asbestos-containing material sprayed on steel girders in many large buildings as a safety feature to prevent buckling in case of fire.

Asbestos was first used extensively in the 1940s. Starting in 1975 it was mostly replaced with synthetic mineral fibers, such as fiberglass or slag wool. However, asbestos is still uses in the manufacture of brake linings and remains as pipe and boiler insulation in hundreds of thousands of workplaces and homes. Despite current regulations mandating adequate training for any worker potentially exposed to asbestos, exposure probably continues among inexperienced demolition workers. The major health effects from exposure to asbestos are, pulmonary fibrosis (asbestosis), and cancer of the respiratory tract, the pleura (Mesothelioma), and in rare cases the peritoreum.

DIAGNOSIS sta Except in localized regions with single industrial exposures, such as coal-mining or granite-quarrying regions, the most frequent inorganic dust-related chronic pulmonary diseases are associated with industries using asbestiform fibers. Asbestos is a generic term for several different mineral silicates, including chrysolite, amosite, anthophyllite, and crocidolite. Besides workers involved in the mining, milling, and manufacturing of asbestos products, workers in the building trades, including pipe fitters and boilermarkers, were exposed to asbestos, which was widely used in construction because its exceptional thermal and electric insulation properties. In addition, asbestos was used in the manufacture of fire-smothering blankets and safety garments, as filler for plastic materials, in cement and floor tiles, and in friction materials, such as brake and clutch linings.

Exposure to asbestos (several mesothelioma cases), is not limited to persons who directly handle the material. Cases of asbestos- related diseases have been encountered in individuals with moderate exposure, such as the painter or electrician who works alongside the insulation worker in a shipyard or the housewife who does no more than shake out and wash her husband’s work clothes. Community exposure has probably resulted from the use of asbestos-containing material sprayed on steel girders in many large buildings as a safety feature to prevent buckling in case of fire.

Asbestos was first used extensively in the 1940s. Starting in 1975 it was mostly replaced with synthetic mineral fibers, such as fiberglass or slag wool. However, asbestos is still uses in the manufacture of brake linings and remains as pipe and boiler insulation in hundreds of thousands of workplaces and homes. Despite current regulations mandating adequate training for any worker potentially exposed to asbestos, exposure probably continues among inexperienced demolition workers. The major health effects from exposure to asbestos are, pulmonary fibrosis (asbestosis), and cancer of the respiratory tract, the pleura (Mesothelioma), and in rare cases the peritoreum.

DIAGNOSIS

The chest radiograph can be used to detect a number of manifestations of asbestos exposure as well as to identify specific lesions. Past exposure is specifically indicated by pleural planques, which are characterized by either thickening or calcification along the parietal pleura, particularly along the lower lung fields, the diaphragm, and the cardiac border. Without additional manifestations, pleural plaques imply only exposure, not pulmonary impairment. Benign pleural effusions may occur, particularly in patients with asbestosis, but are not necessarily restricted to those with overt disease. The fluid is sterile but may be a serous or blood-stained exudate and may occur bilaterally. The

effusion may be slowly progressive or may resolve spontaneously.

The radiographic diagnosis of asbestosis depends on the presence of irregular or linear opacities, usually first noted in the lower lung fields and spreading in the middle and upper lung fields as the disease progresses. An indistinct hearth border or a ground glass appearance in the lung fields is seen in some cases. As the fibrotic changes in the parenchyma begin to coalesce, the patient develops obliteration of entire acinar units, with eventual formation of the classical honeycombed lung, which appears on chest radiographs as course infiltrates with small air spaces. In cases in which the x-ray changes are less obvious, they may show distinct changes of subpleural curvilinear lines 5 to 10 cm in length that appear to be parallel to the pleural surface: the alterations increase the positive predictive value of radiographic evidence from approximately 85% to about 100%.

In general, newly diagnosed cases will have resulted from exposure levels that were present many years before and, in spite of the patients having left the industry, are attributable to that former exposure. Since the patient may be eligible for compensation within a specific time frame after the diagnosis of an asbestos-related disease is made, the physician making the diagnosis should be certain to inform the patient promptly. On occasion, the physician may have reason to suspect ongoing exposure from patient’s current job description or actual monitoring data. In such cases, federal or state health authorities may need to be notified. Present day occupational safety and health regulations, if followed properly, protect workers from exposure.

Casual, non-occupational exposure to undisturbed sources of asbestos-containing materials, for example in walls of schools or other building represents little if any hazard to people who inhabit or work in such buildings. Because the association of smoking and asbestos exposure increases the risk of developing lung cancer, it is extremely important to advise patients with a history of exposure to asbestos to stop smoking. The supportive care is the same as that given to any patient with diffuse interstitial fibrosis from any cause.

Statistics

The chest radiograph can be used to detect a number of manifestations of asbestos exposure as well as to identify specific lesions. Past exposure is specifically indicated by pleural planques, which are characterized by either thickening or calcification along the parietal pleura, particularly along the lower lung fields, the diaphragm, and the cardiac border. Without additional manifestations, pleural plaques imply only exposure, not pulmonary impairment. Benign pleural effusions may occur, particularly in patients with asbestosis, but are not necessarily restricted to those with overt disease. The fluid is sterile but may be a serous or blood-stained exudate and may occur bilaterally. The effusion may be slowly progressive or may resolve spontaneously.

The radiographic diagnosis of asbestosis depends on the presence of irregular or linear opacities, usually first noted in the lower lung fields and spreading in the middle and upper lung fields as the disease progresses. An indistinct hearth border or a ground glass appearance in the lung fields is seen in some cases. As the fibrotic changes in the parenchyma begin to coalesce, the patient develops obliteration of entire acinar units, with eventual formation of the classical honeycombed lung, which appears on chest radiographs as course infiltrates with small air spaces. In cases in which the x-ray changes are less obvious, they may show distinct changes of subpleural curvilinear lines 5 to 10 cm in length that appear to be parallel to the pleural surface: the alterations increase the positive predictive value of radiographic evidence from approximately 85% to about 100%.

In general, newly diagnosed cases will have resulted from exposure levels that were present many years before and, in spite of the patients having left the industry, are attributable to that former exposure. Since the patient may be eligible for compensation within a specific time frame after the diagnosis of an asbestos-related disease is made, the physician making the diagnosis should be certain to inform the patient promptly. On occasion, the physician may have reason to suspect ongoing exposure from patient’s current job description or actual monitoring data. In such cases, federal or state health authorities may need to be notified. Present day occupational safety and health regulations, if followed properly, protect workers from exposure.

Casual, non-occupational exposure to undisturbed sources of asbestos-containing materials, for example in walls of schools or other building represents little if any hazard to people who inhabit or work in such buildings. Because the association of smoking and asbestos exposure increases the risk of developing lung cancer, it is extremely important to advise patients with a history of exposure to asbestos to stop smoking. The supportive care is the same as that given to any patient with diffuse interstitial fibrosis from any cause.