[Pneumothorax].

A pneumothorax is defined by the presence of free air between the pleura visceralis and the pleura partietalis. The lung separates from the chest wall, which then, depending on several parameters, leads to a slight or clinically threatening impairment of lung function. Non-specific signs such as thoracic pain or coughing are common and do not correlate with the extent of the pneumothorax. Almost without exception, the cause of this accumulation of air is a leakage in the lung's surface, which then results in air escaping into the pleural space. Depending on the cause of the "lung leakage", a distinction is made between a primary (idiopathic) spontaneous pneumothorax (PSP) that can be triggered without direct cause, and a secondary spontaneous pneumothorax (SSP) in case of an underlying known lung disease. Further between an iatrogenic pneumothorax in connection with a lung injury caused by medical measures, and a traumatic pneumothorax in the case of an accident-related lung tear. The relevant therapeutic goals are the elimination of the acute symptoms, the reliable achievement of re-expansion of the lungs, and, after appropriate information gathering about the probability and clinical significance of a pneumothorax recurrence and depending on the patient's wish, avoiding a recurrence by means of surgical measures. The therapy options range from a "wait-and-see" procedure, that merely monitors the findings, to a primary video-assisted thoracoscopic surgical therapy with detection and resection of the superficial lung lesion, as well as a measurement to obliterate the pleural cavity that prevents relapse. Regarding "follow-up care" or even behavioral recommendations after a pneumothorax, there are no recommendations that reduce the risk of recurrence.