The disease affects tall, thin men between 20 and 40 years old most frequently. Cigarette smoking and family history are contributing factors.
Traumatic pneumothorax results from an injury, penetrating or otherwise, to the chest.
It is sometimes caused by medical procedures as well as accidental injury. Tension pneumothorax is caused when air enters the pleural space with each inspiration, and excessive pressure builds up. This results in pressure on the lung from air in the pleural space, causing collapse of the lung. Pneumothorax affects 9 out of 100,000 people a year. There is no known prevention, other than to decrease risk by stopping smoking .