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.
Long-term exposure → fibrosis (scarring) of lung tissue with progressive loss of function.
📉 In the UK, a Workplace Exposure Limit (WEL) regulates exposure to keep levels safe.
📖 About
- ⚒️ Exposure to silica (SiO₂) occurs in stone cutting, glass/cement manufacturing, quarrying, foundries, and construction.
- ⏳ The disease can progress even after exposure stops.
📊 Epidemiology
- 📈 Risk is dose-related (level × duration of exposure).
- ⏱️ Usually requires 10–20 years, but acute silicosis can occur with short-term high exposure.
- 🇬🇧 UK data: 14 deaths in 2006, 7 in 2007 from silicosis.
👷 Occupations at Risk
- Quarrying, slate works, potteries, foundries, stonemasonry.
- Construction: cutting/breaking stone, concrete, or brick.
- Industries using silica flour.
🪨 Silica Content of Stones
| Type of Stone | Silica % |
|---|
| Sandstone, gritstone, quartzite | > 70% |
| Concrete, mortar | 25–70% |
| Shale | 40–60% |
| China stone | ≤ 50% |
| Slate | ≤ 40% |
| Brick | ≤ 30% |
| Granite | ≤ 30% |
| Ironstone | ≤ 15% |
| Basalt, dolerite | ≤ 5% |
| Limestone, chalk, marble | ≤ 2% (but may have silica layers) |
🩺 Clinical Features
- 🏃 Progressive exertional breathlessness
- 🫁 Persistent dry cough
- ⚡ Chest pain or tightness
- 🧩 Progressive massive fibrosis (PMF) in severe cases
- 😴 Fatigue, weight loss in advanced disease
⚠️ Complications
- 🧱 PMF: Large fibrotic masses → severe restriction.
- 🦠 TB: Increased risk from impaired macrophage function.
- 🚬 COPD: Risk compounded by smoking.
- 🎗️ Lung cancer: Recognised occupational carcinogen.
- 💔 Cor pulmonale: Chronic PH → right heart failure.
🔎 Investigations
- 🩻 CXR: Nodular opacities, upper/mid zones; "eggshell" hilar calcification (classic).
- 🖥️ HRCT: Detects nodules, fibrosis, emphysema.
- 📉 PFTs: Restrictive pattern, ↓ lung volumes & gas transfer.
- 🧪 BAL: Silica-laden macrophages, milky fluid.
- 🧬 Biopsy: Silica nodules + interstitial fibrosis.
💊 Management
- 🚫 Prevention: Minimise exposure – water suppression, ventilation, dust control.
- 😷 PPE: N95 (or higher) respirators.
- 🚭 Smoking cessation: Reduces COPD and cancer risk.
- 🩺 Monitoring: Regular CXR + PFTs for exposed workers.
- 💨 Supportive care: Bronchodilators, O₂ therapy as needed.
- ⚖️ Legal reporting & compensation: Silicosis is a prescribed occupational disease in the UK.
📚 References
3 Clinical Cases - Silicosis 🌬️🪨
- Case 1 - Chronic simple silicosis ⏳: A 62-year-old man, retired quarry worker with 30 years’ exposure to stone dust, presents with gradually worsening exertional breathlessness. Exam shows fine inspiratory crackles. Chest X-ray reveals multiple small, upper-lobe nodular opacities (<10 mm). Spirometry shows a restrictive pattern with mildly reduced DLCO. Teaching: Chronic simple silicosis typically presents after decades of exposure, with small nodules and slowly progressive fibrosis.
- Case 2 - Accelerated silicosis ⚡: A 44-year-old sandblaster with only 7 years of high-intensity exposure reports breathlessness and chronic cough. CXR and HRCT show widespread nodularity and early conglomerate masses (progressive massive fibrosis). Teaching: Accelerated silicosis develops within 5–10 years of heavy exposure, more aggressive, and often mistaken for sarcoidosis or TB. Risk of complications such as massive fibrosis is high.
- Case 3 - Complicated silicosis with TB co-infection 🦠: A 55-year-old former miner with longstanding silicosis presents with night sweats, weight loss, and haemoptysis. Imaging shows upper-lobe fibrotic masses with cavitation. Sputum smear is positive for acid-fast bacilli. Teaching: Silicosis greatly increases the risk of pulmonary TB (“silicotuberculosis”), and TB must be excluded in any symptomatic patient. Lifelong surveillance for TB and lung cancer is essential.
