How to manage loculations in a patient with a suspected bacterial infection?

Management of Loculations in Suspected Bacterial Infection

When loculations develop in a patient with suspected bacterial pleural infection, immediately flush the chest tube with 20-50 mL normal saline to restore patency, obtain imaging (ultrasound or CT) to identify undrained locules, and initiate intrapleural fibrinolytic therapy with streptokinase (250,000 IU twice daily for 3 days) or urokinase (100,000 IU once daily for 3 days) if drainage remains inadequate. 1, 2

Initial Assessment and Mechanical Management

Restore Tube Patency First

• When chest tube drainage ceases or becomes inadequate, the first step is flushing with 20-50 mL normal saline to ensure the tube is not mechanically obstructed 1, 2, 3
• Inspect for kinking at the skin level, particularly with smaller bore drains, which can be repositioned and redressed using commercial dressings designed to reduce kinking 1, 2
• If the tube remains permanently blocked despite flushing, remove it and insert a new chest tube under image guidance 1

Imaging to Identify Loculations

• Ultrasound is the preferred initial imaging modality, with 81-88% sensitivity and 83-96% specificity for detecting septations, significantly outperforming CT (71% sensitivity, 72% specificity) 1
• Contrast-enhanced CT scanning provides superior anatomical detail for locule mapping, tube position verification, and identifying pleural thickening that may prevent lung re-expansion 1, 2
• Ultrasound should guide all interventions in loculated collections to reduce complications and increase procedural success 1

Intrapleural Fibrinolytic Therapy

Evidence-Based Dosing Regimens

The British Thoracic Society recommends fibrinolytic therapy as it improves radiological outcomes in loculated pleural infections 1, 2:

• Streptokinase: 250,000 IU twice daily for 3 days 1, 2
• Urokinase: 100,000 IU once daily for 3 days 1, 2
• Tissue plasminogen activator (TPA) can be used as an alternative, particularly in patients with prior streptokinase exposure 1

Critical Safety Considerations

• Patients receiving intrapleural streptokinase must receive a streptokinase exposure card, as systemic antibody responses may neutralize future streptokinase administration 1, 2
• For subsequent fibrinolytic indications, these patients should receive urokinase or TPA instead of streptokinase 1, 2
• Monitor for immunological adverse events including fever and leukocytosis, which occur more commonly with streptokinase than urokinase 1

Limitations of Current Evidence

While fibrinolytic therapy improves radiological drainage and may reduce the need for surgery, it remains unclear whether it reduces mortality 1. A meta-analysis concluded insufficient evidence exists to support routine fibrinolytic use for all empyemas, suggesting selective application in patients failing adequate chest tube drainage 1, 4.

Alternative Drainage Strategy: Saline Irrigation

When fibrinolytic therapy or surgery is not suitable, saline irrigation (250 mL three times daily through the chest tube) represents a conditional alternative 3:

• This approach may reduce the need for thoracic surgery based on moderate-quality evidence 3
• Saline irrigation helps maintain tube patency and facilitates drainage of loculated collections 3
• Never add gentamicin or other aminoglycosides to irrigation solution, as they have poor pleural penetration and are inactivated in acidic pleural fluid 3

Surgical Escalation

Indications for Early Surgical Consultation

Obtain surgical consultation when chest tube drainage, antibiotics, and fibrinolytics fail 2:

• Persisting sepsis with persistent pleural collection despite adequate drainage and antibiotics 2
• Organized empyema with thick pleural peel requiring formal thoracotomy and decortication 2
• Multiple loculations positioned on the mediastinum that cannot be accessed percutaneously 1

Thoracoscopic Intervention

• Medical or surgical thoracoscopy allows direct visualization and breakdown of septations under direct vision 1
• In one series, 60% of malignant pleural effusions had septations at thoracoscopy, with 15% having extensive adhesions obstructing two-thirds of the thoracoscopic view 1

Clinical Pitfalls to Avoid

Common Errors in Management

• Do not delay imaging when drainage ceases—residual loculations will not resolve with antibiotics alone and require mechanical or fibrinolytic intervention 1, 5
• Do not use saline irrigation as first-line therapy—it is reserved for situations where fibrinolytics or surgery are contraindicated 3
• Never clamp a bubbling chest drain—if a clamped drain causes breathlessness or chest pain, immediately unclamp it 2
• Loculated effusions are associated with longer hospitalizations and more frequent need for tube thoracostomy compared to non-loculated effusions 5

Prognostic Indicators

• The presence of loculations correlates with exudative pleural fluid chemistries and "extreme" biochemical values, though no radiologic finding is specific for empyema 5
• Pleural thickening on contrast-enhanced CT represents a fibrinous peel that may prevent lung re-expansion despite adequate drainage, though this peel may resolve over several weeks without surgery 1
• Light's criteria for tube thoracostomy are unreliable in patients with loculated parapneumonic effusions or those receiving prolonged antibiotic therapy prior to thoracentesis 5