Pleural effusion + disease Flashcards Preview

*Medicine: Respiratory > Pleural effusion + disease > Flashcards

Flashcards in Pleural effusion + disease Deck (11)
Loading flashcards...

What are key features of pleural effusion?

  • Pleural effusion is fluid in the pleural space
  • Effusions can be divided by their protein content:
    • transudates (<30g/L)
    • exudates (>30g/L)
  • Blood = haemothorax
  • Pus = empyema
  • Lymph w/ fat = Chylothorax
  • Both blood and air = haemopneumothorax


What are risk factors for pleural effusion?

  • Congestive heart failure
  • Pneumonia
  • Malignancy
  • Recent CABG
  • Renal failure
  • Recent MI
  • RA, SLE
  • Drugs (nitrofurantoin)


Pleural effusions may be classified as being either a transudate or exudate according to the protein concentration.

What is the aetiology for transudate (<30) pleural effusions?

  • Heart failure 
  • Hypoalbuminaemia (liver disease, nephrotic syndrome, malabsorption)
  • Hypothyroidism
  • Meigs' syndrome


What is the aetiology of exudate (>30) pleural effusions?

  • Infection → pneumonia, TB, subphrenic abscess
  • Connective tissue disease → RA, SLE
  • Neoplasia → lung ca, mesothelioma, mets
  • Pancreatitis
  • Pulmonary embolism
  • Dessler's syndrome
  • Yellow nail syndrome


What are clinical features of pleural effusions?

  • May be asymptomatic
  • Pleuritic chest pain
  • Cough
  • Reduced chest expansion
  • Dull percussion note
  • Diminished breath sounds
  • Signs of associated disease (malignancy, cachexia, clubbing)


When should imaging be performed for pleural effusion?

  • PA CXR → in all pts
  • USS recommended → increases likelihood of successful pleural aspiration + sensitive for detecting pleural fluid septations
  • Contrast CT → inreasingly performed to investigate underlyin cause, particularly for exudative effusions


How is diagnostic aspiration for pleural effusion carried out?

  • Percuss upper border of pleural effusion
  • Choose site, 1 or 2 intercostal spaces below
  • Infiltrate down to pleura w/ 5-10ml of 1% lidocaine
  • Attach 21G needle to 50ml syringe + insert just above upper border of appropriate rib
  • Draw off 10-30mL of pleural fluid + send to lab
  • Fluid sent for pH, protein, lactate dehydrogenase, cytology + microbiology

If pleural fluid analysis is inconclusive, consider parietal pleural biopsy


What is Light's criteria?

  • Develped in 1972, to help distinguish transudate vs exudate
  • BTS recommend using criteria for borderline cases
  • Exudates = protein > 30 g/L
  • Transudates = protein < 30 g/L
  • If protein level between 25-35 g/L, Light's criteria should be applied, an exudate is likely if at least one of following criteria met:
    • pleural fluid protein divided by serum protein >0.5
    • pleural fluid LDH divided by serum LDH >0.6
    • pleural fluid LDH more than 2/3rds the upper limits of normal serum LDH



What are other characteristics pleural fluid findings?

  • Low glucose → rheumatoid arthritis, TB
  • Raised amylase → pancreatitis, oesophageal perforation
  • Heavy blood staining → mesothelioma, pulm embolism, tuberculosis 


How do you investigate and manage for pleural infection?

  • All pts w/ pleural effusion in association w/ sepsis or pneumonic illness require diagnostic pleural fluid sampling
  • If fluid is purulent or turbid/cloudy, a chest tube should be placed to allow drainage
  • If fluid is clear but pH < 7.2 in pts with suspected pleural infection → place chest tube


How do you manage pleural effusion?

  • Treat underlying cause
  • Drainage → if symptomatic, drain, repeatedly if necessary, fluid best removed slowly (0.5-1.5L/24hr); it may be aspirated in same way as diagnostic tap, or using an intercostal drain
  • Pleurodesis w/ talc may be helpful for recurrent effusions; thorascope mechanical pleurodesis is most effective for malignant effusions; empyemas best drained using chest drain, inserted under USS or CT guidance