A collapsed lung (pneumothorax) is a buildup of air in the space between the lung and the chest wall. As the amount of air in this space increases, the pressure against the lung causes the lung to collapse. This keeps your lung from expanding fully when you try to breathe in. You may have shortness of breath and chest pain.

A collapsed lung may be a life-threatening emergency if the pressure in your chest keeps the lungs from getting enough oxygen into the blood.

Symptoms depend on the size of the collapse. If symptoms are mild, you may not realize you have a collapsed lung. In more severe cases, symptoms will develop quickly and may lead to shock.

Symptoms may include:

• Shortness of breath. This may be mild to severe, depending on how much of the lung is collapsed.
• Sudden, severe, and sharp chest pain on the same side as the collapsed lung.

Symptoms may become worse with altitude changes (such as flying in an airplane, going up a mountain, or going underground or underwater).

A collapsed lung usually is diagnosed through a physical exam and a chest X-ray. Your doctor may also do blood tests to measure the level of oxygen in your blood. You may need a CT scan or ultrasound to diagnose the severity of your condition. These tests will help the doctor plan your treatment.

Treatment can depend on the cause and severity of the collapsed lung. Some people stay in the hospital for treatment. The lung may heal with rest, but you will need to be checked by your doctor. It can take several days for the lung to expand again. In some cases, oxygen may be given (through a mask). More serious cases are treated by placing a needle or a chest tube into the chest cavity. Both of these treatments relieve the pressure on the lung and allow it to expand again. Sometimes surgery is done to help keep the lung inflated. Treatment can also depend on whether the collapse has returned.