Silicosis is a disease of the lungs caused by excessive or chronic exposure to silica dust. Silica is the chief mineral component of sand and is found in many varieties of rock and in mineral ores. Thus, individuals employed in certain occupations, such as sandblasting, mining, grinding, and drilling, are at increased risk for developing the disease.

Silicosis is recognized as one of the earliest known industrial diseases, having been associated since at least the eighteenth century with individuals working as knife grinders or potters. Silica dust is sometimes invisible to the naked eye and can remain airborne for significant periods of time, thus it is necessary for individuals in high-risk occupations to always take protective measures at work in order to prevent silicosis. In the United States, many preventative measures are legally required and federal safety standards for acceptable levels of exposure have been put in place. Consequently, incidence of the disease in the country has steadily decreased over the last several decades. According to statistics compiled by the World Health Organization, however, silicosis is still widespread in many locations around the globe.

When silica dust is inhaled into the lungs, the tiny particles are engulfed by macrophages, large phagocytic cells that play a key role in fighting off bacteria and other foreign substances. The cells are unable, however, to digest the dust and the silica kills them. The dead macrophages then slowly accumulate in the lungs so that they eventually form fibrous nodules, which may further coalesce into sizable masses. These fibrous masses, which are characteristic of silicosis, hinder lung expansion and gas exchange. Thus, the primary symptoms of silicosis are breathing difficulty, coughing, chest pain, and general weakness.

Although most commonly silicosis is a chronic disease that develops over decades from exposure to low concentrations of silica dust, accelerated and acute forms are also known. Accelerated silicosis usually occurs over as few as five to ten years, the hastened development stemming from exposure to unusually high levels of silica dust. Acute silicosis develops even faster, sometimes in as little as a few weeks of heavy contact with silica dust. There is no real cure for any form of silicosis, and the condition can worsen even when exposure is discontinued. The nature of acute silicosis, however, makes it a particularly dire condition that can equally affect the young and the old.

There is no cure for silicosis, but some common treatments can help ease symptoms of the disease. Bronchodilators and cough suppressants are often of use to individuals with less advanced cases of silicosis, and oxygen can be administered to those who experience such difficulty in breathing that they cannot bring enough of the substance into their lungs on their own. Antibiotics can also be used to stave off the many infections that patients with silicosis are predisposed to developing. In some cases, especially when a relatively young individual contracts acute silicosis, a lung transplant may be recommended.

Silicosis at 20x Magnification - Acute silicosis is often treated with steroids, but the prognosis is usually poor because once respiratory failure begins it cannot be readily reversed.

Silicosis at 40x Magnification - Silicosis predisposes patients to develop a number of other diseases, including tuberculosis, pneumonia, lung cancer, bronchitis, and emphysema.