Parapneumonic effusion: Categories, management, and prognosis
| Category | Radiographic appearance | Pleural fluid analysis | Management | Prognosis |
|---|---|---|---|---|
| Category 1 | < 10-mm effusion | No fluid analysis | No drainage needed | Very good |
| Category 2 | > 10-mm effusion and < 50% of the hemithorax | Negative Gram stain and culture pH ≥ 7.2 | No drainage needed | Good |
| Category 3 | ≥ 50% of the hemithorax, or loculations, or thickened parietal pleura | Positive Gram stain and culture pH < 7.2 Glucose < 60 mg/dL | Complete drainage necessary | Poor |
| Category 4 | ≥ 50% of the hemithorax, or loculations, or thickened parietal pleura | Frank pus | Complete drainage necessary | Very poor |
Based on information in reference 5.