Pneumothorax Dr Rob Hicks The lungs are lined with a double layer of membrane (pleura) separating them from the chest wall. If air gets between these two layers, it's called a pneumothorax. This makes the lung collapse, causing chest pain and making breathing difficult.

In this article

What causes it? What are the symptoms?

Who's affected? What's the treatment?

Most commonly air is let in through the rupturing of a little air sac on the surface of the lungs, called a bulla, which has been present from birth. Vigorous exercise, for example, may cause it to burst, allowing the air to escape from the lung.

Air may also escape from the lung as a complication of other lung problems such as asthma and chronic obstructive pulmonary disease, or the rare connective tissue disease Marfan syndrome.

Air may also get into the pleural space from outside the body. This may be caused by a traumatic penetrating chest injury, such as a stabbing, by broken ribs or when surgical operations are performed on the chest.

Chest pain and tightness, shortness of breath and a dry cough are all experienced. The severity depends on how much air gets into the space.

In a tension pneumothorax, which is a medical emergency, the air gets into the space but can't escape. Under these circumstances, chest pain and shortness of breath are severe.

Blood is prevented from returning from the lungs to the heart because of the high pressure caused by the trapped air. This results in low blood pressure and collapse.

Tall, thin, fit men are most often affected. Pneumothorax is six times more common in men than in women, and usually occurs in the 20s or 30s.

In the vast majority of cases only one lung is affected at a time, although very rarely both are. There are reports of sportsmen such as weight-lifters suffering pneumothoraces on both sides at the same time.

After a pneumothorax, there's approximately a one in five chance of it happening again within a year.

Those who smoke are at greater risk of suffering another pneumothorax.

Pneumothorax can be confirmed by an x-ray of the lungs. Small ones will clear without treatment over a few days as the body heals the leak and the air is absorbed.

Larger ones need to have the air drawn out to relieve the symptoms. This is done in hospital with a syringe and needle, or by placing a drainage tube into the space to allow the air to come out again. This is called a chest drain and is inserted under local anaesthetic. It may need to stay in place for a couple of days or a few weeks until the lung heals.

With a tension pneumothorax, the air is released by putting a large bore hollow needle directly into the chest. Immediate relief of symptoms follows.

If air continues to find its way between the pleural layers a process called pleurodesis is used. This uses a chemical irritant to stick the two layers of pleura together, preventing further lung collapse.

This article was last medically reviewed by Dr Rob Hicks in July 2006.