Pneumothorax
(Collapsed Lung)
Medical Revising Authors and Editor: George Schiffman, MD, and Melissa Conrad Stoppler, MD
What is a pneumothorax?
A pneumothorax is a collection of free air in the chest outside the lung that causes the lung to collapse.
What are the types of pneumothorax?
A spontaneous pneumothorax, also referred to as a primary pneumothorax, occurs in the absence of a traumatic injury to the chest or a known lung disease. A secondary (also termed complicated) pneumothorax occurs as a result of an underlying condition.

What causes a pneumothorax?
Spontaneous pneumothorax is caused by a rupture of a cyst or a small sac (bleb) on the surface of the lung. Pneumothorax may also occur following an injury to the chest wall such as a fractured rib, any penetrating injury (gun shot or stabbing), surgical invasion of the chest, or may be deliberately induced in order to collapse the lung. A pneumothorax can also develop as a result of underlying lung diseases, including cystic fibrosis, chronic obstructive pulmonary disease (COPD), lung cancer, asthma, and infections of the lungs.