Definition of Silicosis of The Lung

Silicosis is an obstructive condition of the lungs that develops with repeated and usually long-term exposure to crystalline silica (silica dust). It is a disease of occupational exposure. The silica dust causes irritation and inflammation of the airways and lung tissue.

Scar tissue forms when the inflammation heals, resulting in fibrosis that gradually overtakes healthy lung tissue. The fibrosis continues extending through the lungs even after exposure ends.
Health experts identify three forms of silicosis:

  • Chronic silicosis, the most common form, results from long-term exposure (10 to 20 years or longer) and generally is present as a disease entity in the lungs for 5 to 10 years before symptoms lead to its diagnosis
  • Accelerated silicosis, which shows rapidly progressive symptoms after 5 to 10 years of exposure
  • Acute silicosis, which occurs with exposure to high concentrations of silica dust and shows symptoms within weeks to months of exposure

A secondary complication, progressive massive fibrosis, may occur with accelerated or chronic silicosis. In progressive massive fibrosis the scarring is severe and results in extensive destruction of lung tissue and loss of lung function.

The US Occupational Safety and Health Administration (OSHA) began regulating silica exposure in the 1990s and currently monitors silica levels as well as cases of silicosis. Employees who work in occupations with silica exposure should wear appropriate protective equipment including filtered respirators to limit as much as possible the amount of silica dust they breathe. About 200 people die each year in the United States as a consequence of silicosis.

Symptoms and Diagnostic Path

The primary symptoms are chronic cough and dyspnea (shortness of breath) that worsens with exertion. People who have acute silicosis may also have fever and experience rapid, unintended weight loss. The diagnostic path includes chest x-ray, imaging procedures such as computed tomography (ct) scan, and pulmonary function tests. Characteristic findings with these diagnostic procedures in combination with a history of silica exposure allow the doctor to make a conclusive diagnosis.

People who have silicosis have high risk for developing tuberculosis, and many have latent (asymptomatic) tuberculosis when tested at the time of the silicosis diagnosis. Health experts recommend routine testing for tuberculosis as part of the diagnostic process for silicosis.

Treatment Options and Outlook

Treatment can only help manage symptoms such as cough. There are no specific treatments for the silicosis, and there is no known method of intervention to prevent the condition’s progression. It is crucial to end the silica exposure to end further damage to the lungs, and for those who smoke cigarettes to stop. Treatment may also be necessary for tuberculosis in people who test positive, even if there are no symptoms of the infection. The course of progression often extends over decades, though does result in persistent decline of pulmonary function. Prevention remains the most effective therapeutic approach.

Risk Factors and Preventive Measures

Occupational exposure is the risk factor. Appropriate personal protective equipment in combination with work-site dust management methods has the potential to prevent nearly all cases of silicosis. New cases of silicosis have steadily declined in the United States since the implementation of OSHA regulations limiting exposure, a trend health experts expect to continue. Researchers believe the silica dust interferes with the immune system’s ability to protect against certain kinds of infection, notably tuberculosis. Health experts recommend annual tuberculosis testing for everyone diagnosed with silicosis.

Occupations at Risk for Silicosis

abrasive blastingagricultural plowing
ceramicsfoundry core room
foundry shakeoutglass etching
glass manufacturingjack hammering
stone chipping and crushingmineral mining
potteryrock blasting
road constructionquarry work
rock drillingrock tunneling
sandblastingsoap and detergent manufacturing
masonry workstone grinding
stone cutting


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