Pleural controversy: aetiology of pneumothorax.

Pneumothoraces are classified as spontaneous, traumatic and iatrogenic. Spontaneous pneumothoraces that occur without recognized lung disease are termed primary spontaneous pneumothoraces (PSP), whereas those that occur due to an underlying lung disease are termed secondary spontaneous pneumothoraces. The aetiology of secondary, traumatic or iatrogenic pneumothoraces is not usually debated. However, the aetiology of PSP is potentially controversial and often debated. Therefore, PSP is the focus of this article. There are several purported causes, which include blebs, bullae, emphysema-like changes (ELC) and pleural porosity. The controversy is valid because of the importance of recurrence prevention. This article reviews the current available evidence for the causes of PSP. The causes of PSP are likely a combination ELC, pleural porosity and other potential factors.