Pneumoconioses: Silicosis

Question 1

What is Silicosis?

Answer 1

Due to exposure to silicon dioxide (silica)

Seen most frequently with occupational exposure

I.e. Sandblasters, foundries, silica miners, metal grinders

Question 2

Explain the pathophysiology of silicosis

Answer 2

• Macrophages respond to silica and release fibrogenic factors, leading to fibrosis
• Silica can disrupt phagolysosomes and impair macrophages, HY
• Increases susceptibility to TB

Question 3

Explain the imaging findings of silicosis

Answer 3

CXR
- EGGSHELL calcification of hilar lymph nodes

• Fibrotic nodules seen in the UPPER LOBES of lung

Question 4

Explain the symptoms/signs of silicosis

Answer 4

• Insidious onset of dyspnoea, (starts on exertion then at rest) slowly progressive despite cessation of exposure

Productive cough

Hypoxemia

Diminished breath sounds

Question 5

Silicosis treatment?

Answer 5

Removal from further exposure

Symptomatic treatment (eg, bronchodilators and inhaled corticosteroids)

Rarely lung transplantation

Question 6

What are the risks for silicosis?

Answer 6

Increased risk of:
- Cancer

• Pulmonary hypertension
• Cor pulmonale
• Respiratory failure
• Caplan syndrome
• Secondary tuberculosis – as silica impairs phagolysosome formation by macrophages