Pneumothorax << `noo` moh THAWR aks >> is air or gas in the space between the lungs and the chest wall. A thin, continuous membrane called the pleura covers the outside of the lungs and the inside of the chest wall (see Pleura). Normally, the part of the pleura covering the lungs lies close to the part on the inside of the chest. Only a very thin film of liquid separates the two parts. Ordinarily, no air is present in the space between them. If air or gas enters the pleural space, the two sections of membrane are pushed apart. When a large amount of air or gas collects between the parts of the pleura on one side of the chest, the lung on that side cannot fully expand. Breathing becomes difficult, and the lung may even collapse.
Pneumothorax may result from a wound in the chest, such as a knife wound, or after a sudden tear in the lung. Infection of the pleural space by gas-producing microbes can also cause pneumothorax. Physicians treat pneumothorax by removing the gas by suction, surgically repairing the chest or lung, or prescribing antibiotics when an infection is present.
