Gold Standard Case Presentation

Pleural effusion

Pleural effusion is a very common problem, with multiple aetiologies. It is the accumulation of fluid between the lung and the pleura.

Symptoms and signs:

• Asymptomatic
• Shortness of breath
• Chest pain
• Non-productive cough
• Orthopnoea
• Reduced chest expansion on the affected side
• Reduced breath sounds on the affected side
• Dullness to percussion

Investigations:

• Bloods:
  • Full blood count (raised white cell count, anaemia and platelets)
  • Renal function
  • Liver function
  • Thyroid function tests
  • Bone profile (malignancy)
  • Clotting profile (prior to biopsy)
  • Autoimmune antibody screen
  • Erythrocyte sedimentation rate
• Imaging:
  • Ultrasound (also aid biopsy)
  • Chest X-ray
  • CT-chest if required
• Biopsy of fluids
  • Protein level
  • LDH level
  • Pleural fluid pH (if < 7.2, consider parapneumonic effusion)
  • Cytology for malignancy

Causes of a pleural effusion:

• Transudate (see later)
  • Heart failure
  • Liver cirrhosis
  • Low albumin states
  • Peritoneal dialysis
  • Hypothyroidism
  • Pulmonary embolism
• Exudate (see later)
  • Infection
  • Malignancy (primary or secondary)

Pleural effusions are sub-divided into transudates (protein level < 30g/L) and exudates (protein level >30g/L). The method to differentiate is not only via the protein level, but also Light’s criteria, where the pleural fluid ratio to serum protein in > 0.5; pleural fluid LDH:serum LDH is > 0.6 as well as whether it is > two-thirds higher.

Management depends upon the cause the degree of respiratory distress it is causing. In the case of transudates, it is better to treat the underlying condition. In exudates, this is often not possible and so drainage, sometimes recurrently is often needed along with pleurodesis in recurrent cases that cause respiratory distress.