S

silicosis An obstructive condition of the LUNGS
that develops with repeated and usually long-term
exposure to crystalline silica (silica dust). Silicosis
is a disease of occupational exposure. The silica
dust causes irritation and INFLAMMATIONof the air-
ways and lung tissue. SCARtissue forms when the
inflammation heals, resulting in fibrosis that grad-
ually 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 pro-
  gressive symptoms after 5 to 10 years of expo-
  sure


• 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 sil-
icosis. 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 Admin-
istration (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 fil-
tered 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 con-

sequence of silicosis.

Symptoms and Diagnostic Path

The primary symptoms of silicosis are chronic

COUGH and DYSPNEA (shortness of breath) that

worsens with exertion. People who have acute sil-

icosis may also have FEVERand 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 his-

tory 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 rec-

ommend 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 inter-

vention 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 neces-

sary 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.

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