Synopsis
Diagnose malignant pleural effusion efficiently and choose symptom-led definitive drainage that respects lung expandability, prognosis, cancer treatment, home support and patient preference.
- A malignant pleural effusion usually indicates advanced cancer but prognosis and treatment options vary greatly by tumour type, molecular target, performance status and response to systemic therapy.
- Breathlessness is the main treatment indication. Effusion size alone does not prove that fluid is the cause, especially with embolism, lymphangitic disease, airway obstruction or cardiac comorbidity.
- Use thoracic ultrasound for every fluid procedure and obtain contrast-enhanced staging CT at the appropriate point in the diagnostic pathway.
Key red flags
Severe distress, hypoxaemia, hypotension or major mediastinal displacement from a large effusion requires urgent monitored drainage and simultaneous assessment for other causes.
Investigation priorities
Confirm fluid, septation, pleural abnormality and a safe intervention site.
Management branches
A new unilateral effusion is suspicious for malignancy.
- Use thoracic ultrasound and contrast-enhanced CT to define fluid, pleural targets, primary cancer and alternative causes.
- Perform image-guided aspiration when safe, sending an adequate cytology and cell-block sample plus tests for competing infection or transudative disease.
Key medicines
Local anaesthetic for pleural interventionUse the locally approved lidocaine regimen after weight, allergy, liver and cardiac review, documenting the total dose across skin, tract and pleura.
Analgesia for pleural painUse regular non-opioid treatment with carefully titrated rescue analgesia according to renal function, bleeding risk, frailty and the current BNF.