What is a pneumothorax?

To understand what a pneumothorax is, you have to visualize the lungs inside the chest cavity, surrounded by a double-layered membrane. This membrane is called the pleura, and one layer covers the outside of the lungs, whereas the second layer lines the chest cavity. A pneumothorax is an air pocket that forms between the two layers of the pleura. It can happen spontaneously in a lung affected by emphysema when the damaged and enlarged air sacs (emphysematous bulla) rupture. It can also be brought on by trauma such as an automobile accident or the insertion of a central venous catheter by way of the subclavian vein.

In cystic fibrosis, the formation of these emphysematous bullae is part of the course of the disease. Optimal treatment of cystic fibrosis should delay their formation. Pneumothorax symptoms consist of sudden chest pain that increases with breath intake, combined with a variable increase in breathlessness.

A mild pneumothorax (less than 20% of lung volume as seen on chest X-ray) can be treated by rest under careful observation, and may actually disappear spontaneously. If this should fail, or in more severe cases, a tube will have to be inserted into the pleura through the rib cage under local anesthetic to suck out the air that is there. If a relapse occurs, there are two possible routine treatments. The first is a chemical pleurodesis, which consists of introducing an irritating substance into the pleural space, thus creating inflammation. This reaction will cause the two layers of pleura to join together, preventing air from getting between them. The other solution is surgery.

For recurrent episodes in people with cystic fibrosis facing eventual lung transplantation, it is best to repeat simple drainage rather than resort to chemical pleurodesis or surgery, which cause adhesions (fibrous bands of scar-like tissue) between the surface of the lung and the inside of the chest cavity. Adhesions are a complication that can make lung transplantation more difficult.

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