HealthInfo Canterbury
Think of your lungs as a balloon in a box. Normally the balloon completely fills the box, but if air gets into the box, it pushes the balloon inwards.
In the same way, air can get into the chest from a leak in the lungs. It can also get into the chest from outside the lung. This could be due to a chest wound during a car crash, for example. This causes part of the lung to collapse, making it hard to breath.
A collapsed lung is also called a pneumothorax (new-mo-thor-ax).
The commonest cause of a collapsed lung is a small tear in the lining of the lung for no known reason. This is called a "spontaneous pneumothorax". Tall, thin people are most likely to get a spontaneous pneumothorax. It's also more common in people who smoke.
Sometimes a collapsed lung is caused by a lung disease, such as chronic obstructive pulmonary disease (COPD), lung cancer or pneumonia.
An injury to your chest can also cause a collapsed lung.
If you have a collapsed lung, you'll be short of breath and feel a sharp stabbing pain that is worse when you breathe in or cough. If you're worried that you might have a collapsed lung, you should see a doctor immediately.
To diagnose a collapsed lung, your doctor will examine your chest and arrange a chest X-ray.
Usually, if the air leak is small, your body will reabsorb the air and heal the tear by itself. This may take anything from a few days to several weeks.
Sometimes the air leak is larger, and you'll need help to remove some of the air. In this case you'll have to go to hospital to have the air removed. First, you'll have a local anaesthetic to numb the area, so the procedure doesn't hurt. Then a doctor will insert a needle into the space between your lung and chest wall to draw off the air.
Occasionally, an air leak is large and persistent, so the air needs to be removed with a chest drain. If this happens to you, you'll probably need to stay in hospital for a few days until the air has been drained and your lungs have healed.
Although most people who have a collapsed lung don't experience it again, it happens repeatedly in some people. If this happens, you'll need to see a hospital specialist who may recommend an operation to stop it from happening again. This operation is called a pleurodesis. In it, the surgeon makes the lining of your lungs (the pleura) stick together, either by using a special chemical or by irritating them physically. After this, air leaks will not be able to happen. This procedure doesn't affect the way your lungs work.
After you've been diagnosed with a collapsed lung, it's important not to fly until your doctor is certain that the pneumothorax has gone and has cleared you to do so. It's dangerous to fly with a collapsed lung because the air pressure around your lung doesn't drop when the cabin air pressure drops. This can make the pneumothorax get bigger or damage the surrounding tissue.
If you scuba dive or freedive for sport, you will not be able to again, even after your lung has healed. This is because of the risk of your lung collapsing again when you're under water. If you dive as part of your job, talk to a dive doctor about possible options.
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This page describes the different causes of a collapsed lung, and the treatments.
Written by HealthInfo clinical advisers. Last reviewed June 2021.
Review key: HICLL-290181