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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 contains exposure below a set limit, preventing excessive exposure.

About

• Exposure to silica (SiO₂) is industries and occupations
• Stone cutting, glass and cement manufacturing, quarrying.
• Progressive even when exposure stops

Epidemiology

• Disease is dose-related to exposure levels and time
• Needs 10-20 years of exposure usually but some less
• Usually chronically progressive over years or decades
• Short term high-level exposure can result in an acute silicosis
• in UK 14 deaths from silicosis in 2006 and 7 in 2007.

Occupations with exposure to RCS

• Quarrying, slate works, foundries, potteries, Stonemasonry
• Construction (cutting/breaking stone, concrete or brick)
• Industries using silica flour to manufacture goods
• Different types of stone contain different amounts of silica

Different types of stone contain different amounts of silica

Clinical

• Progressive breathlessness with exertion
• Chest pain: may experience chest pain or tightness
• Cough: A persistent, nonproductive cough is often present
• Progressive massive fibrosis (PMF) may occur
• Fatigue and weakness are common in advanced cases
• Weight loss can occur in advanced disease

Complications

• Progressive Massive Fibrosis (PMF): large areas of dense fibrosis can form, leading to severe respiratory impairment.
• Tuberculosis (TB): increases the risk of developing TB due to impaired macrophage function.
• Chronic Obstructive Pulmonary Disease (COPD): Silicosis can contribute to the development of COPD, particularly in smokers.
• Lung cancer: Silica exposure is a known risk factor for lung cancer.
• Right-sided heart failure (Cor pulmonale): Resulting from chronic lung disease and pulmonary hypertension.

Investigations

• Chest X-ray: Multiple well-circumscribed nodular opacities mid and upper lobe. Eggshell calcification of the hilar lymph nodes is characteristic and Reticulonodular shadowing. Can develop Progressive massive fibrosis.
• High-Resolution CT (HRCT) Scan: detailed imaging, showing nodules, fibrosis, and sometimes emphysematous changes.
• Pulmonary Function Tests (PFTs): restrictive pattern with reduced lung volumes and impaired gas exchange.
• Bronchoalveolar Lavage (BAL): Can reveal the presence of silica particles within macrophages.
• Biopsy: can confirm the diagnosis by showing characteristic silica nodules and fibrosis.

Management

• A preventable occupational lung disease : with no cure.
• Early detection cessation of exposure are essential The occupational history is key.
• Workplace Controls: Use water sprays, ventilation systems, to reduce airborne silica dust.
• Reduce exposure: to silica dust but can still progress as highly fibrogenic. Stop smoking
• Personal Protective Equipment (PPE): wear N95 respirators, when exposed to silica dust.
• Regular Monitoring: regular lung function tests and chest X-rays for at-risk workers.

References

• Silicosis at HMG