Respiratory System >
Pleural Effusion

“A collection of fluid in the pleural cavity

Risk Factors
  • Modifiable: n/a
  • Non-Modifiable:
    • Heart failure
    • Lung cancer
    • Bacterial pneumonia
    • Radiation therapy to the chest
    • Pulmonary embolism
    • Nephrotic syndrome
    • Hypothyroidism
    • Ovarian tumours
    • Tuberculosis
    • Connective tissue disease
Aetiology
  • Whether the fluid in the pleural cavity is exudative (high protein count – > 3g/dL) or transudative (relatively lower protein count – < 3g/dL) helps to determine the cause of the pleural effusion.
  • Exudative causes are related to inflammation: lung cancer, pneumonia, rheumatoid arthritis, tuberculosis
  • Transudative causes are related to fluid moving across into the pleural space: congestive heart failure, hypoalbuminaemia, hypothyroidism, Meig’s syndrome (right-sided pleural effusion with ovarian malignancy)
Pathophysiology
  • Too much pleural fluid in the pleural space:
    • Inflammation → Increased vascular permeability → Proteins and fluid move into pleural space
    • Increased venous pressure → Blood cannot efficiently travel back to the heart → Increased capillary pressure → Increased movement of fluid into the pleural space
    • Hypoalbuminaemia → Reduction in oncotic pressure → Fluid leaks into pleural space
  • Reduction in pleural fluid clearance:
    • Blockage/obstruction to lymph drainage → Fluid builds up in the pleural space
    • Increased venous pressure → Reduced lymph drainage → Fluid builds up in pleural space
    • Injury from chemotherapy/radiotherapy → Damage to lymph vessels → Reduced lymph drainage → Fluid builds up in the pleural space
    • Limitation of respiratory motion → Reduced muscle contraction → Reduced lymph movement → Fluid builds up in pleural space
Clinical Presentation
  • Symptoms:
    • Shortness of breath
    • Dry, non-productive cough
    • Chest pain (sharp, stabbing, worse on inspiration)
    • Orthopneoa
  • Signs:
    • Dullness to percussion over the effusion
    • Reduced breath sounds
    • Tracheal and mediastinal deviation away from the effusion (if large)
    • Decreased chest wall movement
Investigations
  • Imaging:
    • Chest x-ray – blunting of costophrenic angle, fluid in lung fields, meniscus, tracheal and mediastinal deviation
  • Special:
    • Pleural fluid analysis – looking at protein count, cell count, pH, glucose, lactate dehydrogenase, microbiology testing
Management
  1. Treatment of the underlying cause
  2. Pleural aspiration – temporarily relieves pressure although effusion may recur
  3. Chest drain – prevents recurrence
  4. Pleural sclerosis
Complications
  • Empyema (infected pleural effusion)
    • Will be suspected in patients who have improving pneumonia but new or ongoing fever. Treated by chest drain (to remove pus) and antibiotics

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