Home
Print Friendly, PDF & Email

Pleural Effusion

­­

 

Definition of pleural effusion

  • Accumulation of fluid between the pleural layers

 

Epidemiology of pleural effusion

  • Estimated prevalence of pleural effusion is 320 cases per 100,000 people in industrialized countries, with a distribution of etiologies related to the prevalence of underlying diseases.

 

Causes of pleural effusion

  • Can be divided into Transudative or Exudative

 

Transudative pleural effusion

  • Involve increased hydrostatic pressure or reduced osmotic pressure in the microvascular circulation (commonly caused by organ failures)

 

    • Failures
      • Left ventricular failure
      • Liver failure (cirrhotic liver disease)
      • Nephrotic syndrome and hypoalbuminaemia
    • Pulmonary
      • Pulmonary embolism (can be transudates or exudates)
      • Atelectasis
      • Malignancy (5% are transudate)
    • Cardiac
      • Constrictive pericarditis
    • Other
      • Hypothyroidism
      • Meig’s syndrome (ovarian tumours producing right-sided effusion)

 

Exudative pleural effusion

    • Involve an increase in capillary permeability and impaired pleural fluid resorption
    • Infection
      • Parapneumonic
      • TB
      • Empyema
    • Malignancy
    • Rheumatological
      • Rheumatoid arthritis
      • Connective tissue disease (RA, SLE)
    • Pulmonary embolism (can be transudates or exudates)
    • Rare causes
      • Post-MI, pancreatitis, meothelioma, sarcoidosis, asbestosis
      • Drug induced (methotrexate, amiodarone, bromocriptine, phenytoin, nitrofurantoin)
      • Radiotherapy
      • Yellow-nail syndrome, familial Mediterranean fever
      • Lymphangioleiomyomatosis
        • Pneumothoraces and cylothoraces in middle-aged women.
        • Tx: progesterone (but not very good)

 

Presentations of pleural effusion

  • Clinical examination will usually pick up effusion >500ml
    • SOB
    • Cough
    • Chest pain
    • Reduced chest wall movement
    • Mediastinal deviation away (if large)
    • Stony dullness to percussion
    • Decreased breath sounds
    • Decreased Vocal resonance
    • Bronchial breathing or aegophony (bleating vocal resonance) over top of effusion, due to lung compression

 

 

Differential diagnosis of pleural effusion (decreased air entry on auscultation)

    • Consolidation
    • Collapse
    • Pleural thickening

 

Investigation of pleural effusion

    •  Bloods
      • Including amylase, LDH, TFT
      • RF and autoimmune profile
    • ABG
    • CXR
      • Sensitive to effusion >300ml (some places say 200)
    • USS
      • For assessing pleural effusion
      • For guiding aspiration
    • Aspiration
      • Must be USS guided (BTS Guidelines)
      • Note appearance of fluid
      • Sent for
        • Biochem: protein, LDH, pH, glucose
        • Cytology (at least 20ml sample)
        • MCS and AFB
        • pH
        • Other: Amylase, cholesterol, RF and ANA
    • Further tests
      • CT
        • Ideally scan before fluid removal as can improve images of pleural surfaces.
      • Pleural tissue biopsy for histology and TB culture

 

Diagnostic criteria for pleural effusion

    • Normal
      • Clear or straw, pH 7.60-7.64, protein <2, WCC<1, LDH<50% plasma, glucose similar to plasma
    • Transudate
      • Protein <30 g/l:  in patients with normal serum protein
    • Exudate
      • Protein >30 g/l: in patients with normal serum protein
      • Light’s criteria
      • More sensitive for diagnosis of exudative effusions and helpful if fluid protein between 25-35 g/l. Positive if one of these is true:
        • Pleural:serum protein ratio; >0.5 = exudate
        • Pleural:serum LDH ratio; >0.6 = exudate
        • Pleural LDH >2/3 the upper limit of normal serum LDH
      • NB. With diuretics, pleural protein and LDH are generally higher.
    • Empyema
      • pH<7.2
      • Glucose usually <3.3
      • Bacteria in it
      • Fluid LDH generally >1000 in empyema
    • LDH>1000
      • Empyema, malignant, rheumatoid, paragonamiasis
    • Bloody
      • Malignancy, TB, PE, trauma
    • Chylothorax
      • Milky white, chylomicrons, cholesterol>4, Triglyceride level > 110mg/dl
    • High amylase
      • Pancreatitis, malignancy, oesophageal rupture
    • Low glucose or low pH
      • Empyema, malignancy, TB, oesophageal rupture, SLE
    • pH>7.3 in malignancy means:

·        More pleural involvement, higher cytology yield, decreased success in pleurodesis, decreased life expectancy

 

Management of pleural effusion

    • Treat the underlying cause
      •  diuretics, antibiotics, immunosuppressants
    • Aspiration (USS guided)
    • Indications for chest drain:
      • Empyema or parapneumonic effusion with purulent fluid or pH<7.2
      • Malignant effusions which are candidates for pleurodesis
      • Large effusions in acutely unwell patients
    • Pleurodesis
    • Medical or VATs

 

Complications of pleural effusion

    • Respiratory failure
    • Infection and empyema

 

Prognosis of pleural effusion

    •  Dependent on underlying cause

 

Procedure for Thoracocentesis:

For full details on how to perform thoracocentesis, click here. A summary is below:

      • Explain procedure to patient
      • Obtain written consent
        • Complications include pneumothorax, cough, bleeding, empyema, spleen or liver puncture, malignant seeding (particularly in mesothelioma – my need prophylactic radiotherapy to area later)
      • Check clotting (INR <1.5)
      • Must be done under USS Guidance (by a doctor trained in USS – see BTS guidance)
      • Aseptic technique
      • Infiltrate site (skin, intercostals muscle and parietal pleura) with 10ml 1% lidocaine.
      • Aim above the upper border of the appropriate rib to avoid neurovascular bundle that runs below each rib.
      • For Diagnostic Thoracocentesis:
        • Aspirate pleural fluid with a green (21G) needle and 50ml syringe
        • If uncomplicated – no need for CXR post procedure
      • For Therapeutic Thoracocentesis:
        • Hospitals vary as to kit available
        • Verify that insertion site is correct by aspirating fluid with a green (21G) needle
        • Advance a large bore cannula along the same track
        • Remove needle and attach a 3 way tap
        • Aspirate fluid with a 50ml syringe via the 3 way tap and flush the fluid out into container through extension tubing connected to remaining port of 3 way tap.
        • Drain maximum of 1.5l in one go – risk of re-expansion pulmonary oedema
        • Stop aspirating if any resistance felt  or if patient experiences any discomfort or severe coughing
        • CXR post to document extent of improvement and to exclude pneumothorax or trapped lung

 

Click here for medical student OSCE and PACES questions about Pleural Effusion

Common Pleural Effusion exam questions for medical students, finals, OSCEs and MRCP PACES

 

Click here to download free teaching notes on Pleural Effusion: Pleural Effusion

Perfect revision for medical students, finals, OSCEs and MRCP PACES