Infection of the pleural space is an ancient disease, with the earliest recorded description more than 5000 years ago,1 and the first consistent description of its manifestations and treatment credited to the father of modern medicine, Hippocrates.2 Open thoracic drainage, with its associated high mortality, remained the standard treatment for pleural infection until the influenza pandemic of 1919, when closed tube drainage techniques described in the 19th century3 4 were used, and significantly reduced the associated mortality.5 The treatment principles described almost 100 years ago remain to this day in the treatment of pleural infection.6

For many years, pleural infection was considered to be a result of ‘pneumonia gone bad’ with fluid leaking out of the infected lung parenchyma resulting in an infected fluid collection which was poorly accessible to the immune system. The term ‘parapneumonic effusion’ exemplifies this possible aetiology. However, recent studies7 describing the microbiology associated with pleural infection suggest that this may be a too simplistic understanding of the pathological processes occurring. There are markedly different bacteriological patterns in pleural infection7 compared with pneumonia, suggesting microbiologically distinct diseases. Nonetheless, the more widespread use of early antibiotic therapy for pneumonia may be expected to result in decreasing rates of pleural infection, if all pleural infection is simply a complication of pneumonia not treated early enough.

Recent evidence suggests that this may not be the …