2.
What Types of Injuries are Caused by Silica?
Silicosis, lung
cancer, tuberculosis, lupus, scleroderma, and rheumatoid arthritis are among the
diseases caused by the inhalation of respirable crystalline silica particles.
Silicosis is the most common disease caused by breathing silica, and the oldest
known occupational lung disease. When crystalline silica particles are inhaled,
the human body sends defense mechanisms, called macrophages, to try to destroy
the silica particles. However, the silica particles end up destroying the
macrophages.
After this
happens, the lung tissue develops scarring, called fibrosis or Silicosis.
Silicosis is usually found in the upper lobes of the lung. On an x-ray, the
scarring appears round, or nodular. Silicosis is incurable and nonreversible. As
the scarring increases, shortness of breath and breathing difficulty is common.
In extreme cases, death may result. Symptoms of silicosis include cough,
shortness of breath, wheezing, and repeated chest illnesses. Silicosis is
diagnosed through pulmonary function tests, chest x-rays, and a history of
occupational exposure to silica.
There are
three types of silicosis: Chronic Silicosis; Acute Silicosis; and Accelerated
Silicosis.
Chronic
silicosis usually occurs after 10 or more years of exposure to crystalline
silica at relatively low concentrations.
Acute
silicosis occurs from high exposures and can cause symptoms to develop
within in a few weeks or up to 5 years.
Accelerated
silicosis results from exposure to high concentrations of crystalline silica
and develops 5 to 10 years after the initial exposure.
Chronic
silicosis, the most common form of the disease, may go undetected for years in
the early stages; in fact, a chest X-ray may not reveal an abnormality until
after 15 or 20 years of exposure.
Persons with
silicosis are at high risk for developing tuberculosis (TB). Silica is believed
to interfere with the body's immune response to the bacteria that causes TB.
Annual skin testing to check for exposure to TB is recommended, and treatment
with anti-TB drugs is recommended for persons with a positive skin test.
Recent studies
have also linked silica exposure to lung cancer.
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