Pneumoconiosis

Definition | Classification | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Referral

Definition

Pneumoconiosis refers to a group of occupational lung diseases caused by the inhalation of mineral dusts, leading to chronic inflammation, fibrosis, and impaired lung function. Common types include coal workers’ pneumoconiosis (CWP), silicosis, and asbestosis.

Classification

Pneumoconiosis can be classified based on the type of dust exposure:

• Coal Workers' Pneumoconiosis (CWP): caused by inhalation of coal dust.
• Silicosis: caused by inhalation of crystalline silica dust.
• Asbestosis: caused by prolonged exposure to asbestos fibres.

Aetiology

Caused by occupational exposure to specific dust particles:

• Coal Dust: found in coal mining environments, leading to CWP.
• Crystalline Silica: found in industries such as mining, quarrying, and sandblasting, leading to silicosis.
• Asbestos: found in construction, shipbuilding, and insulation industries, leading to asbestosis.

Pathophysiology

The inhalation of mineral dust leads to:

• Deposition of particles in the alveoli and interstitial lung tissue.
• Chronic activation of alveolar macrophages and release of inflammatory mediators.
• Development of fibrosis, resulting in reduced lung compliance and impaired gas exchange.

Risk Factors

• Prolonged occupational exposure to dust (e.g., coal, silica, asbestos).
• Inadequate use of protective equipment (e.g., masks, respirators).
• Smoking, which exacerbates lung damage.

Signs and Symptoms

• Breathlessness: progressively worsening over time.
• Chronic Cough: may be dry or productive.
• Fatigue: due to reduced oxygenation.
• Chest Pain: associated with advanced fibrosis.
• Clubbing: may occur in advanced cases.

Investigations

Key investigations and findings include:

• Chest X-ray:
  • CWP: nodular opacities in the upper lobes.
  • Silicosis: eggshell calcifications of hilar lymph nodes.
  • Asbestosis: pleural plaques or linear opacities in the lower lobes.
• High-Resolution CT (HRCT): better characterisation of fibrosis and nodules.
• Pulmonary Function Tests (PFTs):
  • Restrictive pattern (reduced FVC and TLC).
  • Reduced gas transfer (DLCO).
• Sputum Cytology: to exclude malignancy in asbestos-exposed patients.

Management

1. General Measures:

• Encourage smoking cessation to reduce further lung damage.
• Provide vaccinations (e.g., influenza and pneumococcal) to prevent infections.
• Educate on the importance of occupational safety and protective equipment use.

2. Symptomatic Management:

• Bronchodilators: for symptom relief in cases with airway obstruction.
• Oxygen Therapy: for patients with hypoxaemia.
• Pulmonary Rehabilitation: to improve exercise tolerance and quality of life.

3. Specialist Interventions:

• Consider antifibrotic therapy (e.g., pirfenidone) in selected cases of progressive fibrosis.
• Monitor for and manage complications such as pulmonary hypertension or malignancy (e.g., mesothelioma).

Referral

Refer to secondary care in the following scenarios:

• Respiratory Specialist: for confirmation of diagnosis, advanced imaging, and management of progressive disease.
• Hospital Admission:
  • Severe breathlessness or hypoxaemia requiring oxygen therapy.
  • Acute exacerbation of symptoms, such as infection or pneumothorax.
• Occupational Health Specialist: to assess work-related causes and provide advice on workplace safety.