16th January 2024

Asbestosis

Asbestosis is a fibrotic lung disease caused by asbestos inhalation. Other asbestos-related pleural abnormalities may also present concurrently.

Pathophysiology

The deposition of inhaled asbestos fibres leads to alveolar macrophage alveolitis. This triggers an inflammatory response by releasing cytokines, including tumour necrosis factor (TNF) and interleukin-1 beta. This initiates the fibrotic process, which predominantly occurs in the lower lobes. 

Presentation

• History of progressive dyspnoea
• Cough, wheezing, and sputum production are less common
• Examination findings include bibasal end-inspiratory crackles, and clubbing may also occur
• Interval period between symptoms and exposure is normally over 20 years
• Severity of fibrotic disease is dependent on cumulative dose of exposure

Diagnosis

Imaging- Chest X-Ray/ HRCT

• Reticulonodular changes primarily in the lower lobes
• Concomitant pleural thickening and pleural plaques
• In advanced disease, reticulonodular changes become diffuse

Pulmonary function testing

• Restrictive pattern due to fibrotic changes
• Reduced transfer factor
• An obstructive pattern is uncommon in asbestosis- this is normally secondary to concomitant cigarette smoking history.