How should a pleural effusion be treated?

Treatment of Pleural Effusion

Initial Diagnostic Step: Determine Effusion Type

The treatment of pleural effusion depends entirely on whether it is transudative or exudative, which must be determined first using Light's criteria on pleural fluid analysis. 1, 2

• Use ultrasound guidance for all pleural interventions to reduce pneumothorax risk from 8.9% to 1.0% and improve success rates 1
• Pleural fluid analysis should include protein, LDH, cell count, glucose, pH, Gram stain, culture, and cytology 1, 2
• Light's criteria identifies exudates with high sensitivity but misclassifies 25-30% of transudates as exudates 3
• If heart failure is suspected but Light's criteria suggest exudate, use serum-effusion albumin gradient >1.2 g/dL to reclassify as transudate 3

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Treatment Algorithm by Effusion Type

Transudative Effusions (Heart Failure, Cirrhosis, Nephrosis)

Treat the underlying medical condition—heart failure, cirrhosis, or nephrotic syndrome—as primary therapy. 1, 2

• Therapeutic thoracentesis provides temporary symptomatic relief while treating the underlying condition 1
• Remove no more than 1.5L during single thoracentesis to prevent re-expansion pulmonary edema 4, 1
• Heart failure accounts for >80% of transudates; NT-BNP >1500 μg/mL confirms heart failure as the cause 3
• For recurrent transudative effusions causing severe dyspnea despite optimal medical management, consider pleurodesis 5

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Exudative Effusions: Treatment by Specific Etiology

A. Parapneumonic Effusion/Empyema

All patients require hospitalization with IV antibiotics covering respiratory pathogens plus chest tube drainage if complicated. 1

• Insert small-bore chest tube (14F or smaller) for initial drainage to reduce complications 1
• Indicators requiring drainage: pleural fluid pH <7.0, glucose <2.2 mmol/L, positive Gram stain, frank pus, or loculations 5
• If loculations prevent complete drainage, use intrapleural thrombolytic therapy 5
• If thrombolytics fail, proceed to thoracoscopy or thoracotomy with decortication 5
• Remove chest tube when 24-hour drainage is <100-150mL 1

B. Malignant Pleural Effusion

For symptomatic patients with expandable lung, either talc pleurodesis or indwelling pleural catheter (IPC) are equally effective first-line definitive treatments. 4, 1

Step 1: Initial Assessment

• Perform therapeutic thoracentesis first (removing ≤1.5L) to assess symptom relief and confirm lung expandability 4, 1
• Check post-thoracentesis chest radiograph for mediastinal shift and complete lung expansion before considering pleurodesis 1
• If dyspnea persists after drainage, investigate lymphangitic carcinomatosis, atelectasis, or pulmonary embolism 3

Step 2: Tumor-Specific Systemic Therapy (When Applicable)

For chemotherapy-responsive tumors—small-cell lung cancer, breast cancer, and lymphoma—initiate systemic therapy first, which may be combined with thoracentesis. 4, 1

• Small-cell lung cancer: systemic chemotherapy is primary treatment; pleurodesis only if chemotherapy contraindicated or failed 1
• Breast cancer: hormonal therapy or chemotherapy first; local treatment only if systemic therapy ineffective 4, 1
• Lymphoma: systemic chemotherapy is primary; pleurodesis only for symptomatic recurrent effusions 4, 1
• Non-small cell lung cancer and other chemotherapy-non-responsive tumors: proceed directly to definitive pleural intervention 1

Step 3: Definitive Pleural Management

For expandable lung with recurrent symptomatic effusion:

• Talc pleurodesis: 4-5g talc in 50mL normal saline via chest tube (slurry) or thoracoscopy (poudrage), with 90% success rate 4, 1
• Administer intrapleural lignocaine (3 mg/kg; maximum 250mg) before sclerosant for analgesia 4
• Clamp chest tube for 1 hour after talc instillation 4
• Remove tube when 24-hour drainage is 100-150mL 1
• Avoid corticosteroids during pleurodesis as they prevent successful symphysis 1

For non-expandable lung, failed pleurodesis, or loculated effusion:

• Indwelling pleural catheter (IPC) is preferred over pleurodesis 1
• IPC-associated infections can usually be treated with antibiotics without catheter removal 1
• Non-expandable lung occurs in at least 30% of malignant effusions 1

For patients with very short life expectancy (<1 month) or poor performance status:

• Repeated therapeutic pleural aspiration for palliation without attempting pleurodesis 4, 1
• Recurrence rate at 1 month after aspiration alone is close to 100% 4
• Intercostal tube drainage without pleurodesis is not recommended due to high recurrence rate with no advantage over simple aspiration 4, 1

Step 4: Failed Pleurodesis Options

If initial pleurodesis fails, consider: 4

• Repeat pleurodesis via chest tube or thoracoscopy with talc poudrage
• Pleuroperitoneal shunt (12% occlusion rate; requires good performance status)
• Pleurectomy (12% perioperative mortality; requires careful patient selection)

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Critical Pitfalls to Avoid

• Never attempt pleurodesis without confirming lung expandability on post-thoracentesis chest radiograph—pleurodesis will fail if lung cannot fully expand 4, 1
• Never remove >1.5L during single thoracentesis to prevent re-expansion pulmonary edema 4, 1
• Never delay systemic therapy in chemotherapy-responsive tumors (small-cell lung cancer, breast cancer, lymphoma) in favor of local treatment alone 4, 1
• Never perform intercostal tube drainage without pleurodesis as it has 100% recurrence rate at 1 month 4, 1
• Never use corticosteroids concurrently with pleurodesis as they reduce pleural inflammation and prevent successful symphysis 1
• If bronchoscopy reveals central airway obstruction causing the effusion, remove the obstruction first before attempting pleurodesis 1

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Special Considerations

• Mesothelioma requires multimodality therapy as single-modality treatments have been disappointing 4, 1
• For asymptomatic malignant effusions, observation is appropriate without therapeutic intervention 1
• Tuberculosis and pulmonary embolism should be reconsidered in persistently undiagnosed effusions as they are amenable to specific treatment 3
• Approximately 15% of pleural effusions remain undiagnosed despite repeated cytology and pleural biopsy 3