Abstract
We describe two cases of spontaneous pneumothorax in young healthy adults with no underlying structural lung disease. The onset of pneumothorax was following physical activity including playing musical instruments and blowing of balloons. There is sparse data evaluating the pathophysiology of primary spontaneous pneumothorax in relation to increased mouth pressures. These cases highlight the possible physical effect of valsalva manoeuvre on transpulmonary pressures, and the potential risk of developing pneumothorax in otherwise healthy individuals. This aspect of pneumothorax development is worthy of further exploration, to better elucidate the mechanism and enhance our understanding of this common respiratory presentation.