Related Subjects:
|Idiopathic Pulmonary Fibrosis
|Diffuse Parenchymal Lung disease
|Asbestos Related Lung disease
|Sarcoidosis
|Coal Worker's Pneumoconiosis
|Silicosis
|Farmer's Lung
|Cryptogenic Organising Pneumonia (COP-BOOP)
|Extrinsic Allergic alveolitis (Hypersensitivity)
|Pneumoconiosis
|Cor Pulmonale
Respirable crystalline silica (RCS) is found in stone, rocks, sands, and clays. Exposure to RCS over a long period can cause fibrosis (hardening or scarring) of the lung tissue with a consequent loss of lung function. In Britain, RCS exposure has a workplace exposure limit (WEL), which controls exposure below a set limit, preventing excessive exposure.
About
- Exposure to silica (SiO₂) occurs in various industries and occupations, including stone cutting, glass and cement manufacturing, and quarrying.
- The disease can progress even when exposure stops.
Epidemiology
- Disease is dose-related to exposure levels and duration.
- Usually requires 10-20 years of exposure, but some cases present with less.
- Typically progresses slowly over years or decades, but short-term high-level exposure can result in acute silicosis.
- In the UK, there were 14 deaths from silicosis in 2006 and 7 in 2007.
Occupations with Exposure to RCS
- Quarrying, slate works, foundries, potteries, and stonemasonry.
- Construction (cutting/breaking stone, concrete, or brick).
- Industries using silica flour to manufacture goods.
- Different types of stone contain varying amounts of silica.
Different Types of Stone Contain Different Amounts of Silica
Type of Stone |
Percentage of Silica |
Sandstone, gritstone, quartzite |
More than 70% |
Concrete, mortar |
25% to 70% |
Shale |
40% to 60% |
China stone |
Up to 50% |
Slate |
Up to 40% |
Brick |
Up to 30% |
Granite |
Up to 30% |
Ironstone |
Up to 15% |
Basalt, dolerite |
Up to 5% |
Limestone, chalk, marble |
Up to 2% (but these can contain silica layers) |
Clinical
- Progressive breathlessness, especially with exertion.
- Chest pain or tightness may be present.
- A persistent, nonproductive cough is common.
- Progressive massive fibrosis (PMF) may develop, leading to severe impairment.
- Fatigue and weakness, especially in advanced cases.
- Weight loss is common in advanced disease.
Complications
- Progressive Massive Fibrosis (PMF): Development of large areas of dense fibrosis that severely impair respiratory function.
- Tuberculosis (TB): Increased risk due to impaired macrophage function in the lungs.
- Chronic Obstructive Pulmonary Disease (COPD): Silicosis can contribute to the development of COPD, particularly among smokers.
- Lung Cancer: Prolonged exposure to silica dust is a known risk factor for lung cancer.
- Right-Sided Heart Failure (Cor Pulmonale): Chronic lung disease can lead to pulmonary hypertension and subsequent right-sided heart failure.
Investigations
- Chest X-ray: Shows multiple well-circumscribed nodular opacities, especially in the mid and upper lobes. "Eggshell" calcification of the hilar lymph nodes is characteristic.
- High-Resolution CT (HRCT) Scan: Provides detailed imaging, revealing nodules, fibrosis, and sometimes emphysematous changes.
- Pulmonary Function Tests (PFTs): Typically show a restrictive pattern with reduced lung volumes and impaired gas exchange.
- Bronchoalveolar Lavage (BAL): May reveal silica particles within macrophages, supporting the diagnosis.
- Biopsy: Can confirm the diagnosis by showing silica nodules and interstitial fibrosis.
Management
- Early Detection and Exposure Cessation: There is no cure for silicosis, so prevention through minimizing exposure and early detection is critical.
- Occupational Controls: Using water sprays, ventilation systems, and other controls to reduce airborne silica dust in the workplace.
- Personal Protective Equipment (PPE): Use of N95 respirators when working in environments with silica dust.
- Smoking Cessation: Important to reduce the risk of lung cancer and COPD.
- Regular Monitoring: Periodic lung function tests and chest X-rays for workers exposed to silica.
- Supportive Care: Management of symptoms like cough and breathlessness, including bronchodilators or oxygen therapy if necessary.
- Supervision and Legal Reporting: Reporting cases of occupational silicosis for compensation and implementing safety standards in the workplace.
References