Occupation lung disease caused by inhaling dust containing crystalline silica.

Preventable disease for which there is no effective treatment.

Deaths can occur from inhalation of silica dust within a few months of exposure.

Exposure associated with work in mines, quarries, tunnels, sandblasting, masonry work, foundry work, glass industry, ceramic, potter, cement and concrete production and work in dental laboratories.

Incidence is decreasing with a 93% reduction in overall mortality rate over the last 30 years.

Mortality rate 0.66 per million deaths in 2002.

98% of deaths occur in males.

88% of deaths in white, 12% in black and <1% in other races.

Since 1995 an average of 30 deaths per year in the U.S. among individuals 15-64 years of age.


Prevalent in low and middle income countries.

China with highest burden.

The presentation and severity are influenced by the level and duration of exposure.

In the US the process generally results from low to moderate exposure of silica dust for 20 or more years.

Chest x-ray findings typically show rounded opacities ranging from 1-10 mm, and distributed usually in the upper zones of both lungs in the near symmetric fashion.

CXR changes show hilar lymph nodes with peripheral calcification, are often enlarged and described as eggshell calcification.

Patients have increased susceptibility to mycobacterial infections and the development of fibrosis.

Silicosis is associated with rheumatoid arthritis.

Silica exposure is significantly associated with antineutrophil cytoplasmic and a body-associated vasculitis.

Anti-neutrophil cytoplasmic antibodies, particularly anti-myeloperoxidase antibodies, and other auto antibodies are increased among men with chronic silica exposure.

Progressive masses fibrosis (PMF) that occurs is related to the coalescence of silica nodules to form a mass of hyalinized connective tissue with minimal silica content, cellular infiltrate, and negligible vascularization with central cavities due to ischemic necrosis or mycobacterial infection.

PMF impairs pulmonary function, causes dyspnea and cor pulmonale, and increased spontaneous pneumothoraces.

PMF. Can be fatal.

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