DO NOT USE FOR CLINICAL PRACTICE
Please use current guidelines available on the UHNM intranet for patient treatment
Please use current guidelines available on the UHNM intranet for patient treatment
RECOGNITION AND ASSESSMENT
- Take history, clinical examination and chest X-ray
INITIAL MANAGEMENT
Clinically pleural infection
- See Pleural infection and empyema guideline
Clinically transudate
- e.g. LVF, hypoalbuminaemia, dialysis
- Treat underlying cause
Outcome of treatment
- If the effusion has resolved, stop further investigations for pleural effusion
- If the effusion has not resolved, follow Clinically exudate/unresolved
Clinically exudate/unresolved
- Refer to respiratory physician
- Pleural aspiration under ultrasound guidance - see Pleural aspiration of fluid guideline
- Send samples for: cytology, protein, LDH, glucose, pH, Gram stain, culture and sensitivity and TB cultures
- take blood at same time for LDH, protein and glucose
- If chylothorax suspected, send samples for cholesterol and triglyceride and for centrifuging
- If haemothorax suspected, send sample for haematocrit
- If rheumatoid disease suspected, send samples for glucose and complement
- If pancreatitis, pancreatic pseudocyst, pregnancy, pleural malignancy or acute rupture of oesophagus suspected, send sample for amylase
INTERPRETATION OF RESULTS FROM PLEURAL ASPIRATION
Appearance
- If the fluid has a putrid odour, suspect anaerobic empyema
- If the fluid has food particles, suspect oesophageal rupture
- If the fluid is bile stained, suspect chylothorax (biliary fistula)
- If the fluid is milky, suspect chylothorax/pseudochylothorax
- If grossly bloody, consider malignancy, pulmonary infarction, trauma, benign asbestos effusion or post-cardiac injury syndrome
- If in doubt about haemothorax, request haematocrit on pleural fluid:
- if haematocrit <1%, blood in pleural space is not significant
Biochemistry
- If serum protein is normal and:
- fluid protein >35 g/L, fluid is most likely exudate
- fluid protein <25 g/L, fluid is most likely transudate
- fluid protein between 25 and 35 g/L, use Light’s criteria as below
- Light’s criteria: an exudative effusion is defined when one of the following is present
- pleural fluid protein/serum protein >0.5
- pleural fluid LDH/serum LDH >0.6
- pleural fluid LDH >2/3 x upper limit of normal serum LDH
- Pleural fluid pH
- >7.4 suggests transudative effusion, and virtually rules out tuberculous effusion
- <7.3 suggests exudative effusion
- <7.2 in parapneumonic effusion indicates thick empyema requiring tube drainage
- <7.1 in malignant pleural effusion is a bad prognostic sign (mean survival <6 weeks)
- Pleural fluid glucose <3.3 mmol/L is found in:
- empyema, tuberculosis, malignancy
- rheumatoid disease, SLE
- oesophageal rupture
- Pleural fluid glucose <2 mmol/L or pleural fluid glucose/serum glucose <0.5 mmol/L
- in parapneumonic effusion indicates complicated pleural infection requiring tube drainage
- in malignant pleural effusion is a bad prognostic indicator
- If pleural fluid glucose >1.6 mmol/L or pleural fluid C4 complement >0.04 g/L, effusion unlikely to be caused by rheumatoid disease
- In pancreatitis, pancreatic pseudocyst, pregnancy or pleural malignancy, acute rupture of oesophagus, amylase is high
- higher than upper limit for normal and pleural fluid/serum ratio >1
Cytology
- Positive in only 60% of malignant effusions
- if first specimen negative, refer to respiratory physicians for pleural biopsy
- Pleural lymphocytosis common in malignancy and TB, but not diagnostic
- Pleural eosinophilia not diagnostic
Microbiology and histology in case of possible TB effusion
- Smears for AAFB positive in 10-20% only; cultures positive in 25-50%
- addition of pleural biopsy for TB culture and histology raises diagnostic rate to 90%
SUBSEQUENT MANAGEMENT
Known diagnosis
- If the fluid is a transudate, treat cause
- If the fluid in an exudate, treat appropriately
Still unknown diagnosis
Further investigations
- Request contrast-enhanced CT thorax - see Prevention of contrast-induced acute kidney injury guideline
- Consider pleural biopsy under LA, thoracoscopy, VATS or radiological guidance
- Send biopsy for histology and TB culture together with a repeat pleural aspiration for cytology, microbiology studies +/- special tests
- If symptomatic, drain fluid
Outcome
- If cause found, treat appropriately
- if pleural infection and/or empyema, see Pleural infection and empyema guideline
- If no cause found, reconsider thoracoscopy
- if still no cause found, reconsider treatable conditions such as PE, TB, chronic heart failure and lymphoma
- wait and watch as appropriate