Two layers of thin membrane cover your lungs. The two membranes normally touch each other. But sometimes the space between the membranes, called the pleural space, fills up with air or fluid.
Air in the pleural space is called pneumothorax. Fluid in the pleural space is called pleural effusion Pleural Effusion Two layers of thin membrane, called the pleura, cover your lungs. The two membranes normally touch each other. But sometimes the space between the membranes, called the pleural space, fills... read more 
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What is a pneumothorax?
A pneumothorax is a build-up of air in the pleural space. This causes part or all of your lung to collapse.
A pneumothorax happens when a weak area of your lung tears or your lung is injured so that air escapes into your chest
You may have shortness of breath and chest pain
Doctors can see a pneumothorax on chest x-ray or ultrasound
Doctors usually place a tube in your chest to drain the air
What causes a pneumothorax?
A pneumothorax is caused by a tear or injury to the membrane around your lung. This can happen from:
Weakening in a small area of your lung (this most often happens in tall men under age 40 who smoke)
A long-term lung problem such as COPD Chronic Obstructive Pulmonary Disease (COPD) COPD is a disease in your lungs that makes it hard to breathe. It's hard to push air out of your lungs. Difficulty pushing air out is called chronic airflow obstruction. Smoking cigarettes is... read more
(chronic obstructive pulmonary disease), cystic fibrosis Cystic Fibrosis Cystic fibrosis is a disease that is passed down through families (a hereditary disease). It makes fluids in your lungs, digestive system, and many other organs thick and sticky. Children with... read more , asthma Asthma Asthma is a condition in which the breathing passages (airways) in your lungs get narrow. When the airways are narrow, it's hard to breathe. Breathing often makes a squeaky sound called wheezing... read more 
, or tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a common, serious infection caused by bacteria called Mycobacterium tuberculosis. TB affects millions of people worldwide, particularly in low-resource countries... read more Pressure damage from a breathing machine
What are the symptoms of a pneumothorax?
Symptoms of a pneumothorax depend on how much air enters the pleural space and how much of your lung collapses. Symptoms may happen suddenly or slowly. You may have:
Shortness of breath
Chest pain
Sometimes, pain in your shoulder
If a large pneumothorax happens suddenly, sometimes shock Shock Shock is a medical emergency caused by your organs not getting enough blood and oxygen. It has nothing to do with the "shock" we feel when something scares or upsets us. When your body can't... read more and cardiac arrest
Usually, your body reabsorbs the air, and the pneumothorax goes away over 2 to 4 weeks.
How can doctors tell if I have a pneumothorax?
To tell if you have a pneumothorax, doctors listen to your breathing with a stethoscope. They’ll also do a chest x-ray Plain X-Rays A plain x-ray is an imaging test that takes a picture of the inside of your body. It uses a low dose of x-ray radiation. X-rays show body parts according to how dense (solid) they are. Doctors... read more 
or ultrasound Ultrasonography Ultrasonography is a safe imaging test that uses sound waves to create a moving picture of the insides of your body. Ultrasonography doesn't use radiation (x-rays). Ultrasonography is also called... read more 
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How do doctors treat a pneumothorax?
Treatment depends on how large your pneumothorax is.
If there's only a small pneumothorax, doctors may:
Wait to see if the air goes away on its own
For a larger pneumothorax, or if you're having trouble breathing, doctors will:
Give you oxygen
Place a small plastic tube in your chest (chest tube) to remove the air
Usually the chest tube is connected to a vacuum device to pull the air out. You'll have the chest tube for a couple days until your lung heals.
