| Asbestosis |
The lung diseases caused by dusts are called pneumoconiosis. Certain dusts, particularly those found in mines and other work places, affect the body in different ways. Some are not dangerous. Others bring injury, even death. They are breathed in, entering the lungs with every breath like an invading army. The name of each type of pneumoconiosis comes from the dust that produces it:
Symptoms of a dust diseaseIt is often hard to predict the course of a dust disease. Some workers may suffer little from the disease - even in its most advanced stage - and eventually die of other causes. This is true of silicosis more than asbestosis. But other workers who breathe in harmful dusts over a long period of time may develop serious impairment of function. At the beginning, there may be no symptoms. Shortness of breath is the first symptom. It usually begins some years after the beginning of exposure to the harmful dust. A cough comes next. With extensive scarring of the lung there may be chest pains. The dust deposits, which have slowed up the normal transfer of oxygen into the blood stream, may result in blueness of the lips and ear lobes, in late stages of the disease. Complications - the development of other illnesses - are a serious threat to persons with a dust disease. Tuberculosis is still a problem for silicosis patients, but less than years ago when tuberculosis was common. The quartz dust reacting in the lungs makes the silicotic worker more susceptible to TB. Pneumonia, pulmonary heart disease and lung cancer are complications that often go with a dust disease. Chronic bronchitis and emphysema are frequently seen in workers exposed to dust but these two diseases are really related to the cigarette smoking habit. In the asbestos worker Iung cancer is much more likely to occur in the smoker. SilicosisSilicosis is the most common and important dust disease. Silicosis is a potentially serious disease and it has been since man first worked in stone. Quartz is one of the most widespread of the earth's minerals. It is found in many kinds of rock. Miners looking for anything from coal to gold must frequently drill through quartz or blast quartz rock. The disease has been known by many other names - miner's phthisis, potter's asthma, grinder's rot, stonecutter's disease - depending upon what job is involved. All types of mining which result in the release of silica from hard rock can produce silicosis if the worker is exposed to a significant amount of silica for a long period of time. This includes the mining of gold, lead, zinc, iron, and copper, as well as anthracite coal and some bituminous coal. Other jobs that have led to silicosis are foundry work, sandstone grinding, sandblasting, pottery, and china making and granite carving. Silicosis develops in direct proportion to the amount of silica breathed in, and the length of time the worker is exposed to it. Most doctors believe that silica slowly dissolves within the lungs, and produces a chemical reaction that poisons the cells. After a while, this reaction causes great damage and scarring of the Iungs. Complicating diseases such as tuberculosis and pneumonia may develop. Despite the seriousness of the disease, better methods of protection - and more of them - have greatly reduced the death rate. On-the-job prevention of silicosis, along with increased research into better treatment methods and possible cures, remain a challenge of the future. Elimination of silicosis will depend on methods of prevention that will reduce the level of silica dust in the atmosphere of the worker to the point that the development of the disease will not occur. AsbestosisThe pulmonary fibrosis caused by asbestos fibres, develops after years of exposure to the asbestos fibres. After the fibrosis becomes well established the worker develops increasing breathlessness often with cough, sputum and weight-loss. One of the diseases associated with asbestosis is lung cancer; this usually occurs in the asbestos worker who smokes cigarettes. In fact the risk of the asbestos worker who smokes is 90 times more likely than the non-asbestos, non-smoking worker. As the asbestos fibre in the working environment is reduced to low levels the risk of asbestosis or lung cancer will be reduced and hopefully in time eliminated. MesotheliomaAnother rare but serious malignant disease, mesothelioma of the pleura, is often an asbestos related disease. In contrast to asbestosis which depends on the dosage of exposure to asbestos fibres, the malignant pleural tumour, mesothelioma, is not necessarily related to heavy exposure to asbestos fibre.
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