Spontaneous Pneumothorax and Pneumomediastinum

Gilles Beauchamp, Denise Ouellette

Key Points

  • Primary spontaneous pneumothoraces occur in young patients without lung disease; secondary spontaneous pneumothoraces occur in patients with chronic obstructive pulmonary disease (COPD).
  • The most common cause of a primary spontaneous pneumothorax is the rupture of small subpleural blebs.
  • Pneumothoraces are considered small if they measure less than 3 cm and large if they measure more than 3 cm.
  • Conventional tube thoracostomy with underwater seal drainage remains the procedure of choice for the initial management of moderate to large pneumothoraces.
  • Surgery is indicated if there is recurrence after a first episode.
  • Surgery is indicated at the time of the first episode if the pneumothorax is complicated by persistent air leak, hemothorax, or failure of the lung to re-expand.
  • Resection of blebs and bullae and obliteration of the pleural space by pleurectomy or pleural abrasion, alone or in combination, are the two major goals in the surgical treatment of spontaneous pneumothoraces.
  • With video-assisted thoracic surgery (VATS), analgesic requirements and length of hospital stay are reduced, but the recurrence rate is slightly higher.
  • Rarely, surgeons use chemical pleurodesis as first-line treatment for recurrences of pneumothorax.
  • Spontaneous pneumomediastinum (SPM) is defined as nontraumatic presence of free air in the mediastinum in a patient with no known underlying disease.
  • After specific causes of mediastinal emphysema have been excluded, primary SPM can be treated expectantly.

Pneumothorax is defined by the presence of air in the intrapleural space, with secondary lung collapse. Although such air may originate from various sources, rupture of the visceral pleura with air leakage from the lung parenchyma is by far the most common cause.

Pneumothoraces can be classified as spontaneous, posttraumatic, and iatrogenic (Table 1). Whereas primary spontaneous pneumothoraces occur in young patients without lung disease, secondary spontaneous pneumothoraces occur in patients with clinical or radiographic evidence of underlying lung disease, most often COPD. Posttraumatic pneumothoraces are the result of blunt injuries to the bronchi, the lung, or the esophagus. An open pneumothorax happens when a penetrating trauma induces a disruption of the chest wall.

Table 1: Classification of Pneumothorax



Secondary (underlying pulmonary disease)

  • Chronic obstructive pulmonary disease infection
  • Neoplasm
  • Catamenial


Blunt penetrating





Iatrogenic pneumothoraces may occur during a diagnostic or therapeutic procedure in the hospital environment. Artificial therapeutic pneumothorax refers to the historical treatment for tuberculosis.

Most patients with a spontaneous pneumothorax seek medical attention because of sudden chest pain and dyspnea. If the spontaneous pneumothorax progresses to become under tension, the symptoms are more severe, and significant hemodynamic and respiratory instability may develop and require urgent treatment.

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Last updated: January 3, 2023