Pneumothorax is a collapsed lung caused by air leaking into the chest cavity. There are three main types of air leaks.

  • Pneumomediastinum: Air leaks into the mediastinum, the space in the chest (thoracic) cavity behind the breastbone (sternum) and between the two pleural sacs containing the lungs.
  • Pneumopericardium: Air leaks into the sac surrounding the heart.
  • Pulmonary interstitial emphysema (PIE): Air leaks out of and between the alveoli, the tiny air sacs of the lungs.

Air leaks may occur suddenly or develop slowly. The severity of the condition depends on the location of the leak, how quickly the leak occurs and the amount of air leaked.


  • Chest injury: Injury may include a broken rib or puncture wound. Injury may also result from a medical procedure involving the insertion of a needle into the chest. 
  • Ruptured air blisters: Small air blisters (blebs) may form and burst, causing air to leak.
  • Lung disease: Damage may be caused by several diseases including emphysema, chronic obstructive pulmonary disease (COPD), asthma, cystic fibrosis or pneumonia. In turn, damaged lung tissue is more likely to collapse. 
  • Mechanical ventilation: A ventilator may increase air pressure in the chest, causing the lung surface to rupture and the lung to collapse.
  • Smoking: If you smoke cigarettes, you are at greater risk of developing pneumothorax.


  • Sudden chest pain
  • Shortness of breath 
  • Rapid breathing
  • Chest wall retractions

Altitude changes, such as flying or going underwater, may exacerbate symptoms.

Please note these symptoms may be related to other conditions or health problems. If chest pain is severe, call 911 or go to the emergency department.

Diagnosing Pneumothorax

Pneumothorax and other air leaks may be diagnosed through a physical exam and chest X-ray. The X-ray reveals air in abnormal places, a collapsed lung or abnormal position of chest structures. Sometimes a CT scan or ultrasound is required to provide more detailed images. 


  • Observation: Mild cases may not require anything more than your doctor’s observation.
  • Supplemental oxygen: Oxygen may be delivered through a mask.
  • Needle or chest tube insertion: Air is drained with a needle or a thin tube (catheter) placed through the chest wall. Both procedures relieve pressure on the lung, allowing it to re-expand. 
  • Surgery: More severe conditions may be treated with surgery. Typically, surgery is performed through small incisions using a small, fiber-optic camera.

Spontaneous air leaks that do not cause symptoms or distress may improve on their own without treatment. As the leak seals, air is absorbed into the body.

There are no usual treatments required for pneumomediastinum and pulmonary interstitial emphysema (PIE). These air leaks affect areas that can’t be treated with chest drains.