Pneumothorax

Q: What is pneumothorax?

A: To understand what a pneumothorax is, you have to imagine the lungs housed inside the rib cage, surrounded by an envelope with two sheets. This membrane, called the pleura, has one sheet that covers the outside of the lungs, while the second sheet lines the rib cage. Pneumothorax is an effusion of air that forms between these two sheets. It can be caused spontaneously in lungs affected by emphysema, by the rupture of an emphysema bubble. It can also be caused by trauma, for example a car accident or the installation of a central venous catheter by the subclavian route.

In patients with cystic fibrosis, the formation of these emphysema bubbles is part of the natural history of the disease. The optimal treatment of lung disease should at least delay the formation of these bubbles.

A pneumothorax is accompanied by chest pain — usually sudden — increased by inspiration and associated with a variable increase in shortness of breath.

Treatment for a small pneumothorax (less than 20% of lung volume, as observed on a chest x-ray) can be done by resting under close supervision, and the problem may in fact disappear spontaneously. In case of failure or a greater pneumothorax, it is necessary to insert a drain into the pleura, by local anesthesia, between the ribs, in order to suck in the air that has entered them.

In the case of a recurrence of pneumothorax, the usual treatment has two options. The first solution is chemical pleurodesis. It consists in the administration of an “irritant” into the pleura, which creates an inflammatory reaction. This reaction causes the two layers of the pleura to join together, which prevents air from entering between the two. The other solution is surgery. In the particular case of fibro-cystic patients for whom a possible lung transplant is envisaged, it is preferable, in cases of recurrence, to repeat simple drainage rather than to resort to chemical pleurodesis or surgery. In fact, the latter solutions both lead to the formation of adhesions, fibrous bands of scar tissue that form between the surface of the lungs and the inside of the rib cage. Adhesions are complications that can make lung transplantation more difficult.

Dr Michel Ruel

Joanie Bernier Inf., B.SC

Cystic Fibrosis Clinic at the McGill University Health Center (MUHC)

Montreal (Quebec) Canada

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