Parapneumonic pleural effusions and pleural empyema are clinically challenging conditions, both therapeutically and diagnostically, because of their heterogeneity.1 They range from small, uncomplicated, pleural effusions that do not require specific treatment to multiloculated effusions and empyema with pleural fibrosis, trapped lung, systemic sepsis, respiratory failure, and metastatic infection.¹² Drainage of pleural pus has always been regarded as the key to successful management,^1–3 but newer techniques are now also available to clinicians: image guided small bore catheter insertion, intrapleural instillation of fibrinolytics, and medical thoracoscopy. In the face of these newer approaches several management algorithms and guidelines have been published,¹³ but there are still many unanswered questions about diagnosis and treatment. One of the most important concerns the use of fibrinolytics.

Until recently five small randomised controlled trials of intrapleural fibrinolytics had been reported.^4–8 A double blind trial comparing streptokinase 250 000 IU and urokinase 100 000 IU in 50 patients has shown that both these fibrinolytic agents are equally effective, but …