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
- CT
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
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