Black Lung
Black lung (coal workers' pneumoconiosis) is a lung disease caused by deposits of coal dust in the lungs.
Black lung results from inhaling coal dust over a long time. Although coal dust is relatively inert and does not provoke much reaction, it spreads throughout the lungs and shows up as tiny spots on an x-ray. Coal dust may block the airways. In simple black lung, coal dust collects around the small airways (bronchioles) of the lungs. Every year, 1 to 2% of people with simple black lung develop a more serious form of the disease called progressive massive fibrosis, in which large scars (at least ½ inch in diameter) develop in the lungs as a reaction to the dust. Progressive massive fibrosis may worsen even after exposure to coal dust stops. Lung tissue and the blood vessels in the lungs can be destroyed by the scarring.
In Caplan's syndrome, a rare disorder that can affect coal miners who also have rheumatoid arthritis, large round nodules of scarring develop quickly in the lung. Such nodules may form in people who have had significant exposure to coal dust, even if they do not have black lung.
Symptoms and Diagnosis
Simple black lung usually does not cause symptoms. However, many people with this disease cough and easily become short of breath because they also have an airway disease, such as bronchitis or emphysema, and these are more likely to occur in smokers. The severe stages of progressive massive fibrosis, on the other hand, cause coughing and often disabling shortness of breath.
A doctor makes the diagnosis after noting characteristic spots on the chest x-ray of a person who has been exposed to coal dust for a long time--usually someone who has worked in a coal mine for at least 10 years.
Prevention and Treatment
Prevention is crucial because there is no cure for black lung. Black lung can be prevented by adequately suppressing coal dust at a work site; ventilation systems may help. Face pieces (masks) that filter and purify the air may provide some additional preventive benefit.
Coal workers should have chest x-rays every year, so that the disease can be detected at a relatively early stage. If the disease is detected, the worker should be transferred to an area where coal dust levels are low to help prevent progressive massive fibrosis.
A person who is short of breath may benefit from the treatments used for chronic obstructive pulmonary disease, such as drug therapy to keep the airways open and free of mucus (see Section 4, Chapter 45).
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