It is most commonly caused by: * Esophageal rupture, for example in Boerhaave syndrome * Asthma or other conditions leading to alveolar rupture * Bowel rupture, where air in the abdominal cavity tracts up into the chest. It has also been associated with: * Mycoplasma pneumoniae pneumonia * obesity It can be induced to assist thoracoscopic surgery. It can be caused by a pulmonary barotrauma resulting when a person moves to or from a higher pressure environment, such as when a SCUBA diver, a free-diver or an airplane passenger ascends or descends. In rare cases,<unk>  may also arise as a result of blunt chest trauma (e.g. car accidents, fights, over pressure of breathing apparatus), while still evolving in the same fashion as the spontaneous form.<unk>  is most commonly seen in otherwise healthy young male patients and may not be prefaced by a relevant medical history of similar ailments.
Pneumomediastinum
Hemothorax
Chylothorax
Urinothorax
Hydropneumothorax
Pneumopericardium
Hemopneumothorax
Pulmonary hematoma