SeriesAsbestosis and silicosis
Section snippets
Surveillance and epidemiology
There is no uniform international surveillance and reporting of asbestosis or silicosis. National information about disease incidence, prevalence, and trends is sparse, lacking in comparability, and difficult to obtain. In the USA between 1979 and 1992, 4882 death certificates listed silicosis as an underlying or contributing cause of death. 8761 death certificates listed asbestosis during that period. The number of death certificates that mention silicosis has decreased during the past 25
Exposure settings
The continued occurrence of new cases of silicosis and asbestosis is due, partly, to the diversity of settings in which hazardous exposures continue. Too often, employers fail to recognise and control the hazard, workers are unaware of the risk, and workplace inspectors fail to take samples and to enforce current exposure limits.
Disease descriptions
Silicosis Silica occurs naturally in a variety of crystalline forms, alpha quartz being the most common. Heat can convert amorphous silica into more biologically active forms. The quantity of inhaled crystalline silica, size distribution, and surface characteristics of the dust may affect toxicity. Freshly fractured silica created by grinding or abrasion seems to have greater toxicity.13
Silicosis, the interstitial lung disease caused by the pulmonary response to inhaled crystalline silica, is
Clinical presentation
There are no symptoms or physical signs uniquely associated with the pneumoconioses. Asbestosis and chronic silicosis are generally of insidious onset with gradually progressive dyspnoea, at first noticeable only on exertion and often attributed by the patient to ageing. Cough, dry or with sputum production, may be present, especially in current or former smokers and in those who have worked in dusty environments. Sexual dysfunction is common, although patients rarely associate this problem
Treatment
There is no effective treatment to reverse the course of asbestosis or silicosis. Prevention of these diseases through elimination of hazardous exposure conditions is therefore of primary importance. The clinical approach for people with pneumoconiosis is directed at elimination of progression, amelioration of symptoms, improvement of overall condition, and reduction of risk of associated disorders.
Asbestosis and all forms of silicosis can progress even if exposure ceases.6, 23 Both are
Associated disorders
The most ominous diseases associated with asbestos exposure are cancers of the mesothelium or lung, even in the absence of fibrosis on chest radiography.26 The risk of mesothelioma is unrelated to tobacco use, and no modifiable risk factors have been discovered. Tobacco use seems to increase lung-cancer risk synergistically in asbestos workers. This risk can be reduced over time through smoking cessation. Diligent and continuing effort must be directed toward that goal in all smokers.
Prevention
Effective prevention of asbestosis is a primary responsibility of employers. Physicians have an important supportive role, and may have responsibility for health surveillance of workers.
Exposure control—either through substitution of safer materials or the adoption of control technologies—is the only effective means of prevention of asbestosis or silicosis. Workplace exposures must be monitored frequently, and processes changed when harmful levels of dust are present. Where exposure is
Conclusion
Asbestosis, silicosis, and associated disorders are generally refractory to medical intervention. Cases of asbestosis and silicosis seen now are the result of the failure in the past to apply available information to prevent disease. Despite progress in many industries and occupations, current workplace conditions will inevitably lead to future disease unless a comprehensive and continuing commitment is made to exposure control. Physicians can contribute to disease prevention through accurate
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