Overview
Definition
A fibrotic lung disease caused by the inhalation of crystalline silica dust.
Epidemiology
Seen in miners, sandblasters, quarry workers, and stone cutters. Presents decades after exposure.
Etiology & Risk Factors
- Inhalation of silica dioxide particles. Macrophages engulf particles and release fibrogenic cytokines, then die and release the silica to repeat the cycle.
Clinical Symptoms
- Dyspnea on exertion
- Chronic cough
- Often asymptomatic in early stages
Clinical Approach
Diagnosis
- Chest X-ray / HRCT: Upper lobe predominant, small rounded nodular opacities
- Eggshell calcification of hilar lymph nodes (classic, though not present in all patients)
- PFTs: Can be restrictive or mixed restrictive/obstructive
Management
- No cure. Avoid further exposure.
- Supportive care
- Annual Tuberculosis screening (Silica disrupts macrophage function, drastically increasing the risk of TB)
Complications
- Progressive Massive Fibrosis (PMF)
- Tuberculosis (Silicotuberculosis)
- Increased risk of lung cancer
- Cor Pulmonale