Pleural effusion resident survival guide
Pleural effusion is defined as the presence of excessive fluid in the pleural cavity resulting from transudation or exudation from the pleural surfaces.
Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
- Left ventricular failure
- Nephrotic syndrome
- Pulmonary embolism
Shown below is an algorithm for diagnosing pleural effusion clinically according to an article published by Richard W. Light in New England Journal of Medicine.
|❑ Look for signs suggestive of specific etiology|
|❑ Perform chest X-ray|
|❑ Assess thickness of pleural effusion on USG or lateral decubitus chest X-ray|
|> 10 mm||< 10 mm|
|If CHF is suspected clinically|
If any cause is suspected clinically
If no cause is suspected clinically
❑ Bilateral effusion
❑ No chest pain
|❑ Trial of diuretics||❑ Perform thoracocentesis|
Pleural Fluid Analysis
Shown below are the algorithms for diagnosing pleural effusion after thoracocentesis is done. Algorithm is adapted from the 2010 guidelines issued by British Thoracic Society.
Pleural fluid aspiration
❑ Analyze the appearance of pleural fluid.
|Did pleural fluid tests reveal the cause?|
|❑ Treat accordingly|
If additional tests did not reveal any cause:
If additional tests diagnosed the effusion:
❑ Treat accordingly
|❑ Treat the cause if diagnosed|
If no diagnosis found:
❑ Proceed with imaging guided pleural biopsy OR
|No diagnosis found?|
❑ Proceed with bronchoscopy (if bronchial obstruction is suspected clinically)
|❑ Treat accordingly if diagnosed|
|No diagnosis found?|
|Diagnose as non specific pleuritis|
|❑ Treat accordingly ifdiagnosed|
|Observation if no cause found|
CT: Computerized Tomography
- Do not aspirate bilateral pleural effusion in a clinical setting suggesting of a transudate, unless the effusion fails to respond to therapy.
- Obtain detailed drug history, as some drugs can cause pleural effusion such as methotrexate, amiodarone, phenytoin, nitrofurantoin, beta-blockers.
- Keep a high suspicion for pulmonary embolism in pleural effusion cases.
- Aspirate pleural fluid with a fine bore (21 G) needle and a 50 ml syringe with ultrasound guidance.
- Aspirate pleural fluid into a heparinised blood gas syringe if infection is suspected and pleural fluid pH is needed to be done.
- Send some of the pleural fluid sample in blood culture bottles if infection is suspected, particularly for anaerobic organisms.
- Centrifuge pleural fluid sample if aspiration is milky to distinguish between empyema and lipid effusions.
- Interpretation of centrifuged sample:
|Clear||Empyema (turbid fluid was due to cell debris)|
|Turbid||Chylothorax or pseudochylothorax|
- Suspect urinothorax if pleural fluid smells of ammonia.
- Measure NT-proBNP in cases where Light's criteria diagnose effusion as exudate, but there is a strong clinical suspicion of heart failure.
- Suspect rheumatoid arthritis or empyema if pleural fluid glucose is very low ( < 1.6 mmol/L).
- Send pleural fluid aspirate sample in fluoride oxalate tube if pleural fluid glucose is needed to be measured.
- Measure pleural fluid amylase if following are suspected clinically:
- Perform haematocrit on blood stained pleural effusion. Pleural fluid haematocrit >50% of peripheral haematocrit indicates the presence of hemothorax.
- Consider following causes of pleural effusion based on differential cell count results:
|Differential cell counts|
|Neutrophil predominant||Lymphocyte predominant (>50% lymphocytes)||Eosinophil predominant (≥ 10% eosinophils)|
- Consider following causes if pleural fluid pH is < 7.30:
- Interpret cytology report of pleural fluid as follows:
|Inadequate sample||No mesothelial cells detected|
|No malignant cells seen||Sample is adequate; no atypical cells seen;malignancy is not excluded|
|Atypical cells||Inflammatory or malignant cells; further investigation required|
|Suspicious malignancy||Cells with few malignant features present; no definitive malignant cells present|
|Malignant||Definite malignant cells detected; further immunocytochemistry required|
- Do not allow pleural aspirate to come in touch with local anesthetic or air if pleural fluid pH is needed to be measured.
- Light RW (2002). "Clinical practice. Pleural effusion". N Engl J Med. 346 (25): 1971–7. doi:10.1056/NEJMcp010731. PMID 12075059.
- Maskell N, British Thoracic Society Pleural Disease Guideline Group (2010). "British Thoracic Society Pleural Disease Guidelines--2010 update". Thorax. 65 (8): 667–9. doi:10.1136/thx.2010.140236. PMID 20685739.