Pleurisy

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

Definition

Pleurisy refers to inflammation of the pleura, the two thin layers of tissue that surround the lungs. It causes sharp chest pain that worsens with breathing or coughing.

Aetiology

Pleurisy can be caused by various conditions, including:

  • Infectious causes:
    • Viral infections (e.g., influenza, COVID-19).
    • Bacterial pneumonia leading to pleural involvement.
    • Tuberculosis (TB) affecting the pleura.
  • Non-infectious causes:
    • Pulmonary embolism causing pleural irritation.
    • Autoimmune diseases (e.g., rheumatoid arthritis, lupus).
    • Malignancy (e.g., lung cancer, mesothelioma).
    • Pneumothorax (air in the pleural cavity).
    • Trauma to the chest wall.

Pathophysiology

The pleura normally allows smooth lung expansion with minimal friction. In pleurisy:

  • Inflammation causes the pleural surfaces to rub against each other, resulting in pain.
  • In severe cases, pleural effusion (fluid in the pleural space) may develop, reducing friction but potentially causing breathlessness.

Risk factors

  • Recent viral or bacterial respiratory infection.
  • History of pulmonary embolism.
  • Autoimmune conditions (e.g., lupus, rheumatoid arthritis).
  • Chest trauma or surgery.
  • Smoking (increases risk of lung infections and malignancy).

Signs and symptoms

  • Pleuritic chest pain: sharp, stabbing pain worsened by deep breathing, coughing, or movement.
  • Shortness of breath: due to pain or associated pleural effusion.
  • Fever: if an infection is the underlying cause.
  • Pleural rub: a scratchy or creaky sound heard on auscultation.
  • Cough: typically dry, unless associated with an infection.

Investigations

  • Chest X-ray:
    • May show pleural effusion, pneumonia, or lung collapse.
    • Normal in early or mild pleurisy.
  • Blood tests:
    • Full blood count (FBC) to check for infection or inflammation.
    • CRP (C-reactive protein) may be elevated in infection or autoimmune conditions.
    • Autoimmune screen (e.g., ANA, RF) if lupus or rheumatoid arthritis is suspected.
  • ECG: to exclude cardiac causes of chest pain.
  • Ultrasound: to assess for pleural effusion.
  • CT thorax: if malignancy or pulmonary embolism is suspected.
  • Pleural fluid analysis (if pleural effusion is present):
    • Protein levels (to differentiate transudate vs. exudate).
    • Cell count and microscopy to check for infection.
    • PH and glucose levels (low in malignancy or infection).

Management

1. Pain Management:

  • First-line: NSAIDs e.g naproxen, ibuprofen.
  • Alternative: paracetamol if NSAIDs are contraindicated.

2. Treat Underlying Cause:

  • Viral pleurisy: supportive management with analgesia and hydration.
  • Bacterial infection: antibiotics if bacterial pneumonia is suspected.
  • Pulmonary embolism: anticoagulation therapy if confirmed.
  • Autoimmune conditions: consider corticosteroids or immunosuppressants.

3. Management of Pleural Effusion (if present):

  • Small effusions: monitor if asymptomatic.
  • Large effusions: thoracentesis (pleural tap) for drainage if causing significant breathlessness.

4. Supportive Measures:

  • Encourage deep breathing exercises to prevent lung collapse.
  • Monitor for worsening symptoms such as increasing breathlessness.

Referral

Refer to secondary care in the following scenarios:

  • Respiratory specialist: if recurrent or unexplained pleurisy is suspected.
  • Hospital admission:
    • Severe breathlessness or hypoxaemia.
    • Suspected malignancy requiring urgent evaluation.
    • Large pleural effusion requiring drainage.
 
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