Overview of pleural effusion in adults

This topic covers information on the diagnosis of pleural effusion in adults. For diagnosis of pleural effusion and empyema in children, seek specialist advice. Information on diagnosis and management of pleural effusion and empyema in children is available from The Royal Children’s Hospital (Melbourne) website.

Management of pleural effusion depends on accurate diagnosis of the cause. To help diagnose the cause, determine whether pleural effusions are transudates or exudates using Light’s criteria; see the British Thoracic Society guidelines for detailed information on categorisation of pleural effusions. Most transudates occur in patients with heart failure, liver cirrhosis, nephrotic syndrome or those receiving peritoneal dialysis.

Use direct ultrasound guidance to sample pleural fluid by aspiration. This can be safely undertaken at the bedside using a 21 gauge needle and a syringe. Obtain as large a sample as possible to analyse for biochemistry (which may include pH, lactate dehydrogenase [LDH], protein and glucose), cytology and culture (including for mycobacteria). Note the gross appearance of the fluid (eg colour, clear or cloudy appearance, evidence of blood and clots, purulence). If clinical suspicion of tuberculosis is high, consider a pleural biopsy.

For management of parapneumonic effusion and thoracic empyema, see Parapneumonic effusion and thoracic empyema.

For management of malignant pleural effusion, see Management of malignant pleural effusion in adults.