Silicosis - Lung fibrosis caused by inhalation of silica particles

Silicosis is one of the oldest occupational disease that has been identified.  It still claims many lives, mainly in developing countries.  This disease is caused by inhalation of free silica particles.

 Causes

Silica is present in nature. When it is disturbed by sandblasting and mining, the particles can be suspended in atmosphere.  It can be inhaled and can settle in the lungs.  Respiratable silica is invisible to the naked eye and can remain airborne for long periods of time.  It can also travel in the air and can affect people outside the risky areas.  In the respiratory tract, it can produce inflammatory reaction, ending up in scarring or fibrosis of lung tissue.  The damage is irreversible and progressive, leading to respiratory failure and death. The disease can progress even after the exposure is stopped.

Types of silicosis

1)      Acute form caused by exposure to high concentration of silica for very short periods of time.

2)      Chronic type caused by low dose exposure for long periods of time- twenty to thirty years.

 Workers involved in

–        sandblasting

–        stone cutting

–        mining

–        road building and construction

–        quarrying

–        ceramics

–        glass cutting

 Symptoms

 -         cough with sputum production

-         progressive shortness of breath

-         exercise intolerance

-         wheezing

-         weight loss

-         malaise

Diagnosis

Detailed history of exposure and occupation are key to diagnosis.  Chest x-ray can show small round opacities in the lung.  Ct scan can show emphysematous changes and pleural thickening.  Pulmonary function tests can show obstructive pattern and restrictive pattern as the disease progresses.  Arterial blood gases show a decrease in oxygen.

Treatment

Prevention is key. Exposure to dust particles should be avoided.  Dust controlling facilities such as face masks and showering after exposure play an important role. These patients are at increased risk of developing TB, lung cancer and lung infections. 

Complications

 Respiratory failure, right heart failure, lung cancer and death