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Silicosis is the permanent scaring of the lungs caused by inhaling silica (quartz) dust.
- Silicosis is the oldest known occupational lung disease. It develops in people who have inhaled silica dust for many years.
- Silica is the main constituent of sand. It’s exposure is common among metal miners, sandstone and granite cutters, foundry workers and potters.
- Silica dust, when inhaled passes into the lungs and scavenger cells like macrophages engulf it.
- Enzymes released by the scavenger cells caused the lung tissue to scar.
- At first, the scarred areas are tiny round lumps (simple nodular silicosis), but eventually they combine into larger masses (complicated silicosis).
- These scarred areas cannot transfer oxygen into the blood normally.
- As a result, lungs become less flexible and breathing takes more effort.
- The symptoms usually appear after 20 or more years of exposure to the dust.
- In occupations such as sandblasting, tunneling and manufacturing abrasive soaps, in which high levels of silica dust is produced, symptoms appear in less than 10 years.
- The least serious type of lung disease from silica is simple nodular silicosis.
- People with nodular silicosis have usually have no trouble breathing, but they may cough and produce sputum (phlegm) because their large airways are inflamed (a condition known as chronic bronchitis).
- People who have more serious type, complicated silicosis, may cough, produce sputum and have serious shortness of breath.
- At first, shortness of breath may occur only during exercise, but eventually it occurs even during rest.
- Breathing may worsen for years even after a person stops working with silica.
- The lung damage strains the right side of the heart and can lead to a type of heart failure (known as corpulmonale), which can be fatal.
- Also, when exposed to the organism that causes tuberculosis, people with silicosis are many times more likely to develop tuberculosis than people without silicosis.
- Silicosis is diagnosed when someone working with silica has a chest x-ray that shows distinctive patterns of scarring and nodules.
- Breathing tests are often performed to determine if lung function is impaired.
- Controlling silica dust in the work place is the key to preventing silicosis.
- When dust cannot be controlled in industries such as sand blasting, workers should wear protective gears like hoods that supply clean external air or special masks that efficiently filter out the tiny particles.
- Such protection may not be available to all the people working in dusty areas (welders and painters for example).
- So, whenever possible, abrasives other than sand should be used.
- Workers exposed to silica dust should have regular chest x-rays – every 6 months for sand blasters and every 2 to 5 years for other workers – so that the problems can be detected early.
- If the x-ray shows silicosis, a doctor will probably advise the worker to avoid continued exposure to silica.
- Silicosis cannot be cured, but its progression can be slowed if exposure to silica is avoided, especially at an early stage of the disease.
- A person who has difficulty in breathing, may benefit from the treatments used for chronic obstructive pulmonary disease, such as drug therapy to keep the airways open and free of mucus
- Because people with silicosis have a high risk of developing tuberculosis, they should have regular checkups that include a tuberculosis skin test.
People at risk
- Lead, copper, silver and gold miners.
- Certain coal miners like roof bolters.
- Foundry workers
- Sandstone or granite cutters
- Tunnel workers
- Workers who make abrasive soaps
- Tombstone makers
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