What Causes a Pneumothorax?

There are many causes of pneumothorax. Any condition that can result in air entering the pleural space is a culprit. There are generally three sources of air: the lung, the atmosphere, and the abdomen.

The lung: The lung is the most frequent source of air causing pneumothorax. There are a large number of conditions of the lung that can lead to this problem. They include:

• Congenital blebs
• Giant blebs
• Emphysema
• Trauma
• Lung cancer
• Granulomatous disease
• Latrogenic (secondary to medical treatments)

Blebs are similar to large, air-filled blisters that exist on the surface of the lung. The most common form of blebs is congenital blebs; that is, the patient is born with them. These congenital blebs are typically located at the apex, or top of the lung, in tall thin individuals. Like any thin walled blister, the bleb can eventually rupture, leaking air into the chest. This air collects outside the lung, causing the lung to be pushed away from the chest wall, or “collapse”. The patient typically has a sharp pain in the chest, and becomes short of breath. The same events occur whether the disease process is due to congenital blebs, giant blebs, or emphysema.

The patient who presents with a pneumothorax for no apparent reason is said to have a spontaneous pneumothorax. Typically, at the time of the first pneumothorax, a chest tube is placed and the air leak allowed to heal. If the patient heals the leak, but the pneumothorax recurs, then the patient should usually undergo surgical therapy in trauma, the lung leaks air into the chest due to an injury. The lung is injured by very high pressures from a blunt force, or is pierced by a sharp object or bullet. The mechanism of pneumothorax is the same as for blebs.

Occasionally, lung cancers and infections in the lung will create an air leak, and a pneumothorax occurs.

Finally, procedures such as lung biopsy or drainage of fluid with a needle will create a leak from the lung.

The atmosphere: Air enters the chest from the atmosphere due to a defect or hole in the chest wall. The most common causes are trauma and drainage procedures. Trauma may result in a small or large defect in the chest wall through which air may enter the chest. In drainage or biopsy procedures, a needle is passed through the chest wall to drain fluid or to perform a biopsy. When this is done, there is always a chance that air will be introduced into the chest, and a pneumothorax result.

The abdomen: Air enters the chest from the abdomen occasionally during laparoscopic surgery. Carbon dioxide is insufflated into the abdomen under pressure during laparoscopy. Occasionally, a patient will have a small defect in the diaphragm that allows the carbon dioxide to enter the chest, thereby causing a pneumothorax. What is the treatment of pneumothorax?