Classification of parapneumonic pleural effusion (PPE)/empyema (modified from).
| Uncomplicated PPE | Complicated PPE | Empyema | |
| Pleural morphology | Thin, permeable | Fibrin exudation, septations | Thickened, gratulation tissue (wound healing tissue), septa (septal walls), and ventricles |
| Pleural punctate, macroscopic aspect. | Clear | Cloudy | Purulent turbid |
| pH | > 7,3 | 7,1-7,2 (7,3) | < 7,1 |
| LDL (lactate dehydrogenase) (U/l) | < 500 | > 1.000 | > 1.000 |
| Glucose (mg/dl) | > 60 | < 40 | < 40 |
| Cytology | PMN + | PMN ++ | PMN +++ |
| Microbiology | Sterile punctate | Occasional positive (microscopic and culture). | Frequently positive (microscopic and cultural) |
| Therapy | Systemic antibiosis (antibiotic administration) | Systemic antibiosis; thoracic drainage and fibrinolysis (enzymatic cleavage of fibrin) | Systemic antibiosis; suction-irrigation drainage (possibly at multiple sites?); thoracoscopy (endoscopic reflection of the pleural cavity) if necessary |
PMN (= polymorphonuclear neutrophils; cells of nonspecific defense belonging to the white blood cells).