What Causes Spontaneous Pneumothorax?

Pneumothorax is the condition of the lungs in which the air is filled in the pleural cavity. It is the cavity which surrounds the lungs and helps in the movement of muscles of lungs during respiration. Thus, the air exerts the pressure on the lungs, removes the air filled in the lung leading to collapse of the lungs. The symptoms of pneumothorax include shortness of breath, fatigue, chest pain and cyanosis. The treatment of pneumothorax depends upon the underlying disease conditions and in some case, surgery is required.

Spontaneous Pneumothorax

Pneumothorax can be divided in to two types, traumatic pneumothorax and non-traumatic pneumothorax. Traumatic pneumothorax is defined as the pneumothorax caused due to injury such as motor accident, or bullet wound. Non-traumatic pneumothorax occurs without any injury. As the non-traumatic pneumothorax is caused spontaneously, it is also known as spontaneous pneumothorax. Spontaneous pneumothorax is further subdivided in to two types, the primary spontaneous pneumothorax and the secondary spontaneous pneumothorax.

What Causes Spontaneous Pneumothorax?

Spontaneous pneumothorax is of two types, primary spontaneous pneumothorax and secondary spontaneous pneumothorax. The causes of both the types of pneumothorax are different as the primary does not have the underlying medical condition related to respiratory system while the secondary also involves the respiratory disease such as asthma, chronic obstructive pulmonary disorder, or emphysema.

The cause of Primary spontaneous pneumothorax is the bleb and the bulla. Both of these structures are the air filled spaces which gets ruptured leading to the release of gases in the pleural cavity. The bleb is the subpleural emphysematous vesicle, while bulla is subpleural paraseptal emphysematous lesion. Further another cause for the development of primary spontaneous pneumothorax is that the air may enter in the pneumomediastinum and then into the alveolar space. The conclusion can be drawn is that there may be a rupture of alveoli-pleural barrier due to the difference in the pressure of alveolar space and pleural space resulting in the presence of air in pleural cavity and causing pneumothorax. Some researchers concluded that the exposure to loud music also plays an important role in precipitating spontaneous pneumothorax. The other factors that contribute to the occurrence of primary spontaneous pneumothorax includes the hereditary effect, anatomical abnormalities, ischemia on the apical part, inflammation and the abnormal expression of the connective tissue.

The secondary spontaneous pneumothorax is the condition in which the condition of the lung is already compromised. If the pneumothorax occurs in such lung, it requires immediate medical attention. Following are the causes of secondary spontaneous pneumothorax:

  1. Underlying Respiratory Diseases: As the secondary spontaneous pneumothorax is characterized by the existence of the disease of the lungs, however these underlying diseases are also responsible for pneumothorax. These diseases may include chronic asthma, emphysema, chronic obstructive pulmonary disease, and cystic fibrosis.
  2. Chronic Infections: The infection and corresponding inflammation of the lungs plays a major role in the development of spontaneous pneumothorax. These infections may include pneumonia and tuberculosis.
  3. Lung Diseases: There are diseases other than infection, which are present in the lungs. These diseases such as sarcoidosis and idiopathic pulmonary fibrosis are also responsible for spontaneous pneumothorax.
  4. Abnormality In The Connective Tissue: The abnormality in the connective tissue also promotes pneumothorax. Rheumatoid arthritis and ankylosing spondylitis are the disease in which connective tissue becomes abnormal.
  5. Cancer: Cancer of the lungs is also major contributing factor for secondary spontaneous pneumothorax.


The cause of the spontaneous pneumothorax is complex and hard to identify as compared to traumatic pneumothorax. In the spontaneous pneumothorax, the cause of development of pneumothorax is not exactly known; however, the prominent theory in support of the occurrence is the presence of bleb and bulla and the release of air on their rupture. The secondary spontaneous pneumothorax has some form of underlying disease such as chronic asthma, cystic fibrosis or chronic obstructive pulmonary disease. Other cause of secondary spontaneous pneumothorax includes infection, lung diseases or cancer. More aggressive treatment is required in case of secondary pneumothorax as compared to primary pneumothorax.

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