A pneumothorax refers to a collection of air in the pleural cavity (between the lung and the chest wall) resulting in collapse of the lung on the affected side. The extent of the collapse of the lung is dependent upon the amount of air that is present. Pneumothoraces can be classified into:[1]
Primary spontaneous pneumothorax: pneumothorax occurring in healthy people.
Secondary pneumothorax:
Associated with underlying lung disease - eg, rupture of a congenital bulla or a cyst in chronic obstructive pulmonary disease (COPD).
The consequences of a pneumothorax in patients with pre-existing lung disease are significantly greater and the management is potentially more difficult.
Other causes of a pneumothorax may include:
Traumatic pneumothorax follows a penetrating chest trauma such as a stab wound, gunshot injury or a fractured rib.
Iatrogenic pneumothorax may follow a number of procedures such as mechanical ventilation and interventional procedures such as central line placement, lung biopsy and percutaneous liver biopsy.
Catamenial pneumothorax refers to pneumothorax at the time of menstruation.[2] The aetiology is endometriosis. It represents 3-6% of spontaneous pneumothorax in women. Patients are typically aged 30-40 years with a history of pelvic endometriosis in 20-40%. Over 90% occur in the right lung and it occurs within 72 hours from the onset of menstruation. In women receiving hormonal treatment, 50% will have a recurrence within a year.