What are the four types of pneumothorax?

Pneumothorax is when air gets into the pleural cavity, often leading to a fully or partially collapsed lung. There are four types of pneumothorax. They are:

• traumatic pneumothorax. This occurs when an injury to the chest (as from a car wreck or gun or knife wound) causes the lung to collapse.
• tension pneumothorax. This type can be fatal. It occurs when pressure inside the pleural cavity is greater than the outside atmospheric pressure. It can force the entire lung to collapse and can push the heart toward the lung, putting pressure on both.
• primary spontaneous pneumothorax. This happens when a small air bubble on the lung ruptures. These may happen for no obvious reason or while undergoing changes in air pressure (like when scuba diving or mountain climbing).
• secondary spontaneous pneumothorax. This typically happens to those who already have lung disease. As the lung is already compromised by disease and may have diminished capacity, this can be a serious complication.