Pneumoconiosis is a lung condition caused by the inhalation of dust, characterized by formation of nodular fibrotic changes in lungs.

Many substances can cause pneumoconiosis including asbestos, silica, talc and metals.

Depending on the type of dust, variants of the disease are considered. For example there are silicosis, also known as grinders' disease; and pneumosilicosis, which is caused by the inhalation of the dust of stone, sand, or flint containing silica. Because many common minerals contain silica, there are different types of silicosis.

The term Pneumonoultramicroscopicsilicovolcanoconiosis and some variants thereof turned out to be a hoax created as a word puzzle.

Incidents

The Hawk's Nest incident was one of the earliest and most prominent incidents of large-scale silicosis deaths. But while stringent occupational reforms have largely eliminated it in Europe, the US National Institute for Occupational Safety and Health (NIOSH) estimates that a million workers remain at risk to silicosis, 100,000 of whom are at high risk. They estimate 59,000 will develop adverse effects.

But due to pressure from industry groups, its effects are little known and hardly acted upon. A 1992 Houston Chronicle investigation found "silicosis is often misdiagnosed by doctors, disdained by industry officials and unknown to the very workers who stand the greatest chance of getting it. ... Old warnings and medical studies have been ignored, products falsely advertised and government rules flouted--especially with regard to sandblasting, an activity so hazardous that NIOSH recommended its banning in 1974."

Black lung disease

Black lung disease, also known as coal miners' pneumoconiosis, is caused by long exposure to coal dust. Since dust that enters the lungs can neither be destroyed or removed by the body, it remains, causing inflammation and scarring (fibrosis). The most usual symptom is shortness of breath; it can also lead to emphysema and heart failure.

It is a common affliction of coal miners and others who work with coal, similar to silicosis from inhaling silica dust, and to the long term effects of tobacco smoking.

Pathology

Continuous accumulation of collagen around inhaled silica crystals produces pulmonary fibrotic hyalinized (silicotic) nodules. Microscopically, they present concentric laminated collagen fibers (blue) and tend to become confluent, compressing adjacent alveola. Silica crystals appear as empty cleft-like spaces. With progression, perivascular and peribronchic fibrosis (collagen deposits) will produce pulmonary hypertension and respiratory failure.

External links

Image of Silicotic nodules