The reported incidence of primary spontaneous pneumothoraces is 18-28 per 100 000 per year for men and 1-6 per 100,000 per year for women, though this data from Sweden and the USA is more than 20 years old. A more recent study in England and Wales [1] found the hospital admission rate for all spontaneous pneumothoraces to be 17 and 6 per 100 000 per year for men and women, respectively.
Changes in clinical guidelines since may have lead to a reduction in the proportion of patients admitted. The same study reported the mortality from spontaneous pneumothoraces in England and Wales between 1991 and 1995 to be 1.3 per million per year for men and 0.6 per million per year for women.
Definition
A pneumothorax is a collection of gas in the pleural space that results in a variable amount of lung collapse on the affected side. By definition, spontaneous pneumothoraces occur in the absence of any trauma (including iatrogenic causes) to the chest wall.
Primary spontaneous pneumothoraces occur in people with no underlying lung pathology.
Secondary spontaneous pneumothoraces occur in patients with pre-existing lung parenchymal or pleural pathology (e.g. asthma, lung carcinoma).