Scarring of the lung tissue caused by long-term exposure to coal dust, also known as black lung
- More common over the age of 40
- More common in males due to increased risk of occupational exposure
- Caused by exposure to coal dust; smoking aggravates the disease
- Genetics is not a significant factor
Coalworkers’ pneumoconiosis is a serious lung disorder caused by inhaling coal dust. The dust causes a gradual build-up of scar tissue in the lungs over many years, which leads to progressive and disabling shortness of breath. The severity of the condition depends on the degree to which a person has been exposed to coal dust. Pneumoconiosis was once a common disease in coalmining areas. However, the decline of the coal industry and improved safety practices have made it increasingly rare in developed countries.
What are the causes?
In pneumoconiosis, minute particles of coal dust are inhaled into the lungs, where they reach the alveoli (air sacs). Over many years of exposure, the dust causes irritation of the lung tissue. This form of the disorder is known as simple pneumoconiosis. Continuing exposure to the dust results in a serious complication known as progressive massive fibrosis (PMF). In this condition, lung tissue becomes heavily scarred. The disorder is likely to be worse if the coal dust contains a high level of silica (see Silicosis). Smoking causes the condition to progress more rapidly.
What are the symptoms?
Although the condition does not initially produce symptoms, the following symptoms of simple pneumoconiosis and PMF may develop over time:
Coughing up black sputum.
Shortness of breath on exertion that becomes progressively worse.
People with simple pneumoconiosis or PMF are also more susceptible to many other lung disorders, including chronic bronchitis (see Chronic obstructive pulmonary disease) and tuberculosis. Coalworkers who also have rheumatoid arthritis may develop Caplan’s syndrome, in which inflamed nodules form in the lungs.
As simple pneumoconiosis or PMF progresses, breathing difficulties may become so severe that respiratory failure develops.
How is it diagnosed?
Your doctor will probably base the diagnosis on your occupational history and symptoms. He or she may arrange for a chest X-ray and lung function tests to confirm the diagnosis and assess existing damage to the lungs. You will probably also have tests that measure the levels of oxygen and carbon dioxide in your blood (see Measuring blood gases). These tests show how effectively oxygen from your lungs is reaching the bloodstream.
What is the treatment?
You should not smoke and should avoid further exposure to coal dust as far as possible. If you have simple pneumoconiosis and are no longer exposed to the dust, no treatment is necessary because the disease will not progress. If you have PMF, the symptoms may get worse even after exposure to the dust has stopped. Although there is no complete cure for PMF, your doctor may prescribe bronchodilator drugs and oxygen therapy (see Home oxygen therapy) to help to relieve your symptoms. You may also need to have chest physiotherapy regularly to help to remove mucus from the airways, and a friend or member of the family may be taught how to do this.
Can it be prevented?
In most developed countries, there are regulations governing the coalmining industry that require adequate ventilation in the workplace and other safety measures. Appropriate face masks and equipment to control dust may also be needed for people who work underground. Workers exposed to coal dust should have a chest X-ray every few years to detect the presence of simple pneumoconiosis before PMF develops.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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