Synopsis
Identify complicated parapneumonic effusion or empyema early, use pleural chemistry and imaging correctly, and combine antibiotics with prompt effective drainage and timely surgical escalation.
- Pleural infection includes complicated parapneumonic effusion and empyema; pus or organisms in pleural fluid establishes the need for drainage regardless of pH.
- Persistent fever, pleuritic pain or sepsis despite pneumonia treatment should prompt thoracic ultrasound, even when the chest radiograph shows only basal shadowing.
- Use ultrasound guidance for aspiration and drain placement. Septations and echogenic fluid support complexity but do not replace fluid analysis.
- Measure pleural pH immediately in a heparin-free blood-gas syringe without local-anaesthetic contamination. Air, delay and lidocaine can materially distort the result.
- In non-purulent fluid, pH at or below 7.20 indicates high risk and usually warrants a drain if safely accessible. Intermediate pH requires LDH, glucose, imaging and clinical context under the BTS pathway.
- Send pleural fluid in both sterile containers and inoculated blood-culture bottles to improve microbiological yield, alongside cytology when malignancy remains possible.
- Start antibiotics covering likely community- or hospital-acquired organisms and anaerobes, then narrow to cultures and clinical response. Duration is individualised and usually extends beyond initial intravenous therapy.
- A small-bore chest tube is usually adequate initially when positioned in the collection and flushed according to protocol.
- If drainage has stopped with residual collection, combined intrapleural tPA and DNase can improve drainage; do not use either agent alone as a substitute.
- Failure of sepsis and collection to improve requires early thoracic-surgical review. Do not wait for prolonged organ failure before discussing VATS.
Key red flags
Pneumonia with persistent fever, pleuritic pain, systemic inflammation and a pleural collection whose low pH, low glucose, high LDH or septation predicts failure of antibiotics alone.
Frank pus, a positive pleural culture or a thick infected collection establishes pleural infection and requires drainage plus antibiotics.
Recent surgery, aspiration, hospital pneumonia or pleural instrumentation increases resistant Gram-negative and staphylococcal risk and changes empirical antibiotics.
Persistent sepsis, inflammatory markers or residual loculated fluid despite a patent drain suggests malposition, obstruction, separate locules, bronchopleural fistula or organised disease.
Lung abscess, infected bulla, subphrenic collection, oesophageal leak or malignant effusion can mimic empyema and make blind drainage hazardous.
Investigation priorities
Confirm pleural fluid, estimate volume and complexity, and identify a safe sampling or drain site.
Management branches
Pneumonia has pleural fluid, persistent sepsis or pleuritic pain.
- Assess sepsis severity, oxygenation and organ function, start appropriate antibiotics promptly and request respiratory or pleural review.
- Use thoracic ultrasound to confirm fluid and perform image-guided aspiration when the result will change drainage.
- Send immediate pH, microbiology, glucose, LDH and other tests required by the differential.
- Drain frank pus, positive microbiology or high-risk biochemical fluid when safely accessible.