Pneumoconiosis

What is it?

Pneumoconiosis is a lung condition that is caused by inhaling particles of mineral dust, usually while working in a high-risk, mineral-related industry. At first, irritating mineral dust can trigger lung inflammation, which causes areas of the lung to be temporarily damaged. Over time, these areas can progress to form tough, fibrous tissue deposits. This stage of pneumoconiosis is called fibrosis. Fibrosis stiffens the lungs and interferes with the lung's normal exchange of oxygen and carbon dioxide.

There are several different types of pneumoconiosis. In the United States, the most common types include:

• Asbestosis — Asbestos is the general name for a family of irritating fibrous minerals that are mined from underground deposits and used in the manufacture of home insulation, fireproof materials, tiles for floors and ceilings, automobile brake linings, and other products. Workers with the highest asbestos exposure include miners, construction workers, demolition workers, shipbuilders and auto mechanics who work with brakes. Asbestos exposure also can affect people who live or work in buildings where asbestos-containing building products are deteriorating. In most cases, signs of asbestosis do not develop for 20 or more years after a person is first exposed to asbestos dust.
• Silicosis — This form of pneumoconiosis affects people who work with silica, usually in the form of quartz that is found in sand, sandstone, slate, some clays, granite and other ores. Workers with the highest exposure to silica include sandblasters, miners, tunnel builders, silica millers, quarry workers, foundry workers and those who make ceramics or glass. Silicosis can cause progressive fibrosis in the lung with a significant decrease in lung function, especially in cigarette smokers.
• Coal worker's pneumoconiosis — This form of pneumoconiosis is caused by inhaling carbon particles from coal, graphite, lamp black or carbon black. It most often affects people who mine, process or ship coal; graphite miners; and workers who manufacture synthetic graphite, lamp black or carbon black. Like silicosis, coal worker's pneumoconiosis can cause significant fibrosis, primarily in miners who have worked for decades without protective equipment.
• Talc pneumoconiosis — This is caused by exposure to talc dust, usually during talc mining or milling. Talc pneumoconiosis also can lead to lung fibrosis.
• Kaolin (china clay) pneumoconiosis — This pneumoconiosis is caused by inhaling kaolin, an ingredient used in the manufacture of ceramics, paper, medicines, cosmetics and toothpaste. Workers who mine, mill or bag kaolin are at risk.
• Siderosis of the lung — This pneumoconiosis, also known as welder's lung or silver polisher's lung, is caused by inhaling iron particles. Although welder's lung often looks abnormal on a chest X-ray, it usually does not cause any symptoms.
• Other pneumoconiosis — Less often, pneumoconiosis can be caused by inhaling barium sulfate, tin oxide, compounds containing hard metal (cobalt and tungsten carbide) or other forms of mineral dust.

Symptoms

Pneumoconiosis sometimes does not cause any symptoms. When symptoms develop, they can include:

• cough (with or without mucus)
• wheezing
• shortness of breath, especially during exercise.

If pneumoconiosis causes severe lung fibrosis, breathing can become extremely difficult. When this happens, the patient's lips and fingernails may have a bluish tinge. In very advanced disease, there also may be signs of leg swelling caused by too much strain on the heart.

Diagnosis

Your doctor will ask about your exposure to mineral dusts, the number of years you were exposed, and whether you used protective clothing and equipment. Your doctor will examine you, paying special attention to your chest. This will be followed by a chest X-ray, which will be compared to a set of standard X-rays published by the International Labor Office for the evaluation of pneumoconiosis. Your doctor may order breathing tests, called pulmonary function tests. In some patients, a more detailed computed tomography (CT) scan of the chest is necessary. Less often, a doctor will order a test called a bronchoscopy with a lung biopsy. In this test, a flexible tube is inserted into a lung and a small piece of lung tissue is removed to be examined in a laboratory.

Expected duration

Pneumoconiosis causes permanent lung changes. However, you can stop it from getting worse.

Prevention

Pneumoconiosis almost always can be prevented. To reduce your risk, you can:

• Limit work-related exposure to mineral dusts — Workers who routinely deal with mineral dusts always should use approved measures (protective equipment and clothing) to limit their exposure and keep from bringing mineral dust home on their clothing. If a mask or respirator is worn as a protection against dust, it must fit properly and be used according to the manufacturer's directions.
• Prevent exposure to asbestos at home — Check your house, especially if you own an older house, for areas of exposed asbestos-containing insulation or deteriorating asbestos. The asbestos in these areas must be removed or safely sealed away (encapsulated) professionally.
• Avoid cigarette smoking — Smoking worsens the harmful effects of pneumoconiosis. If you smoke, ask your doctor about proven ways to quit.

Treatment

If you have pneumoconiosis and you develop breathing problems, your doctor will advise you to avoid further exposure to the mineral dust. He or she may prescribe one or two medicines that are inhaled to decrease inflammation in your airways and to help keep your bronchial tubes open. If the oxygen level in your blood is below 90%, you may need to breathe additional oxygen at home. Also, to help protect your damaged lungs against respiratory infections, your doctor will recommend immunization with the influenza (flu) and pneumococcal vaccines. If you develop a respiratory infection, you may need to be treated with antibiotics.

When pneumoconiosis causes extreme breathing problems, a lung transplant is the only cure.

When to call a professional

Call your doctor promptly if you have symptoms of pneumoconiosis and you have worked at a job where there is a high risk of exposure to mineral dust.

Prognosis

The outlook for this disease depends on the specific type of pneumoconiosis, the length of exposure to mineral dust, the level of exposure and whether the patient is a smoker.

In the long term, people with asbestosis and talc pneumoconiosis have an increased risk of lung cancer and malignant mesothelioma (cancer of the membranes lining the lungs and abdominal cavity). The risk of lung cancer is especially high in smokers with asbestosis.

Because male workers fill most of the jobs that carry high risks of pneumoconiosis, the majority of deaths from pneumoconiosis occur in men.

Additional info

National Heart, Lung, and Blood Institute (NHLBI)
https://www.nhlbi.nih.gov/

American Lung Association
https://www.lung.org/

U.S. Environmental Protection Agency (EPA)
https://www.epa.gov/

National Institute for Occupational Safety and Health
https://www.cdc.gov/niosh/