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Last updated: April 16, 2021

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Pneumothorax develops when air enters the pleural space as the result of disease or injury. This leads to a loss of negative pressure between the two pleural membranes, which can result in the partial or complete collapse of the lung. Pneumothorax is classified as spontaneous or traumatic. Spontaneous pneumothorax can be further classified as primary (i.e., no underlying lung disease) or secondary (i.e., due to underlying lung disease). Any type of pneumothorax can progress to tension pneumothorax, which is a life-threatening variant of pneumothorax. Patients with pneumothorax usually present with sudden-onset dyspnea, ipsilateral chest pain, diminished breath sounds, and hyper-resonant percussion on the affected side. Tension pneumothorax further manifests with distended neck veins, tracheal deviation, and hemodynamic instability. There should be a high index of suspicion for both conditions on clinical evaluation. Unstable patients with tension pneumothorax require immediate needle decompression. Chest x-ray may be used to confirm the diagnosis in stable patients. Small pneumothoraces may resorb spontaneously, but larger defects usually require placement of a chest tube.

Epidemiological data refers to the US, unless otherwise specified.

  • Pneumothorax: a collection of air within the pleural space between the lung (visceral pleura) and the chest wall (parietal pleura) that can lead to partial or complete pulmonary collapse. May be classified as: [4]
  • Spontaneous pneumothorax
    • Primary spontaneous pneumothorax: occurs in patients without clinically apparent underlying lung disease
    • Secondary spontaneous pneumothorax: occurs as a complication of underlying lung disease
    • Recurrent pneumothorax: a second episode of spontaneous pneumothorax, either ipsilateral or contralateral
  • Traumatic pneumothorax: a type of pneumothorax caused by a trauma (e.g., penetrating injury, iatrogenic trauma)
  • Tension pneumothorax: a life-threatening variant of pneumothorax characterized by progressively increasing pressure within the chest and cardiorespiratory compromise

Spontaneous pneumothorax

Traumatic pneumothorax

Any type of pneumothorax may lead to tension pneumothorax.

Increased intrapleural pressure → alveolar collapse → decreased V/Q ratio and increased right-to-left shunting. [5]

Patients range from being asymptomatic to having features of hemodynamic compromise. [6]

P-THORAX: Pleuritic pain, Tracheal deviation, Hyperresonance, Onset sudden, Reduced breath sounds (and dyspnea), Absent fremitus, X-rays show collapse.

General principles [8]

  • The diagnosis of pneumothorax is usually confirmed by chest x-ray.
  • Tension pneumothorax is primarily a clinical diagnosis and prolonged diagnostic studies should be avoided in favor of initiating immediate treatment.

In cases of tension pneumothorax, immediate decompression is a priority and should not be delayed by imaging.


Chest x-ray [6][8]

Ultrasound [9]

Chest CT [6]

  • Indications
    • Uncertain diagnosis despite chest x-ray and complex cases
    • In suspected underlying lung disease, to determine the likelihood of recurrent disease
    • Detailed assessment of bullae
    • Presurgical workup
  • Findings: similar to CXR

Determination of pneumothorax size

The size of a pneumothorax is assessed via imaging (e.g., CXR, CT chest). How a pneumothorax is measured depends on regional guidelines, hospital policies, and personal preferences:

  • Apex-to-cupola distance [8]
  • Interpleural distance at the level of the lung hilus [6]
  • Collins method: Calculated pneumothorax size in percent of hemithorax [15][16]
    • The interpleural distance on a PA CXR is measured in centimeters at three points.
    • Apex-to-cupola distance (A)
    • Midpoints of upper (B) and lower (C) half of collapsed lung
    • Pneumothorax size as a percent of the ipsilateral hemithorax = 4.2 + 4.7 x (A + B + C)

Laboratory studies

Laboratory analysis is generally not indicated.

See “Chest pain: Differential diagnoses“ and “Differential diagnoses of dyspnea.”

The differential diagnoses listed here are not exhaustive.

Approach [6][8]

In every patient with pneumothorax who requires mechanical ventilation, immediate tube thoracostomy should be performed first.

Positive pressure ventilation can turn a simple pneumothorax into a life-threatening tension pneumothorax.

Stability criteria for spontaneous pneumothorax [8]

All of the following must be present for the patient to be considered stable:

  • Respiratory rate < 24 breaths/minute
  • SpO2 (room air): > 90%
  • Patient able to speak in complete sentences
  • HR 60–120/minute
  • Normal BP

All other patients are considered unstable.

Respiratory support

Management based on pneumothorax type and size

Tension pneumothorax, unstable patients, and bilateral pneumothorax [6][7][8]

Tension pneumothorax is a clinical diagnosis and a medical emergency requiring immediate chest decompression.

Primary spontaneous pneumothorax (stable patient) [6][8]

Secondary spontaneous pneumothorax, age > 50 years, or history of smoking (stable patient) [6][8]

Open pneumothorax

  • Simple partially occlusive dressings taped at 3 out of 4 sides of the lesion
  • Followed by thoracostomy
  • Observe for development of tension pneumothorax.


  • Needle thoracostomy
  • Chest tube placement [23]
    • Indications: see above
    • Procedure
      • Most commonly in the 4th–5th intercostal space (nipple line), between the anterior and midaxillary line (safe triangle )
      • Rarely: second intercostal space, midclavicular line (Monaldi drain)
        • The intercostal space is very narrow at this site and the pectoralis muscle must be penetrated. [23]
        • Primarily used for emergency chest decompression
      • Connect tubing to water seal or suctioning [6]
      • Always check CXR after the procedure is complete.
  • Surgery
    • Indications [6]
    • Procedures
    • Approaches
      • Stitching of the leak or resection of the lung regions that have bullae, if necessary.
      • Pleurodesis
        • Mechanical/surgical: pleural abrasion, pleurectomy (complete or incomplete) [6]
        • Chemical/pharmacological (administration into the pleural space): talc powder , doxycycline, minocycline [6][8]

Always check a CXR after chest tube placement or needle thoracostomy.

Acute management checklist for tension pneumothorax [7][24]

Acute management checklist for spontaneous pneumothorax [6][8][24]

All patients

Unstable patients or bilateral pneumothorax

  • Chest tube insertion with water seal with or without suction
  • Order repeat CXR after chest tube insertion.
  • ICU transfer
  • Consult thoracic surgery.

Primary spontaneous pneumothorax (stable patient)

Secondary spontaneous pneumothorax (stable patient)

We list the most important complications. The selection is not exhaustive.

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  1. Choi WI. Pneumothorax. Tuberc Respir Dis (Seoul). 2014; 76 (3): p.99-104. doi: 10.4046/trd.2014.76.3.99 . | Open in Read by QxMD
  2. MacDuff A, Arnold A, Harvey J. Management of spontaneous pneumothorax: British Thoracic Society pleural disease guideline 2010. Thorax. 2010; 65 (Suppl 2): p.ii18-ii31. doi: 10.1136/thx.2010.136986 . | Open in Read by QxMD
  3. Leigh-Smith S, Harris T. Tension pneumothorax--time for a re-think?. Emergency Medicine Journal. 2004; 22 (1): p.8-16. doi: 10.1136/emj.2003.010421 . | Open in Read by QxMD
  4. Baumann MH, Strange C, Heffner JE, et al. Management of spontaneous pneumothorax: an American College of Chest Physicians Delphi consensus statement.. Chest. 2001; 119 (2): p.590-602. doi: 10.1378/chest.119.2.590 . | Open in Read by QxMD
  5. Alrajab S, Youssef AM, Akkus NI, Caldito G. Pleural ultrasonography versus chest radiography for the diagnosis of pneumothorax: review of the literature and meta-analysis. Critical Care. 2013; 17 (5): p.R208. doi: 10.1186/cc13016 . | Open in Read by QxMD
  6. Thomsen L, Natho O, Feigen U, Schulz U, Kivelitz D. Value of Digital Radiography in Expiration in Detection of Pneumothorax. RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren. 2013; 186 (03): p.267-273. doi: 10.1055/s-0033-1350566 . | Open in Read by QxMD
  7. Kong A. The Deep Sulcus Sign. Radiology. 2003; 228 (2): p.415-416. doi: 10.1148/radiol.2282020524 . | Open in Read by QxMD
  8. Clark S, Ragg M, Stella J. Is mediastinal shift on chest X-ray of pneumothorax always an emergency?. Emergency Medicine Australasia. 2003; 15 (5-6): p.429-433. doi: 10.1046/j.1442-2026.2003.00497.x . | Open in Read by QxMD
  9. Noppen M. Spontaneous pneumothorax: epidemiology, pathophysiology and cause. European Respiratory Review. 2010; 19 (117): p.217-219. doi: 10.1183/09059180.00005310 . | Open in Read by QxMD
  10. Husain L, Wayman D, Carmody K, Hagopian L, Baker W. Sonographic diagnosis of pneumothorax. Journal of Emergencies, Trauma, and Shock. 2012; 5 (1): p.76. doi: 10.4103/0974-2700.93116 . | Open in Read by QxMD
  11. Collins CD, Lopez A, Mathie A, Wood V, Jackson JE, Roddie ME. Quantification of pneumothorax size on chest radiographs using interpleural distances: regression analysis based on volume measurements from helical CT.. American Journal of Roentgenology. 1995; 165 (5): p.1127-1130. doi: 10.2214/ajr.165.5.7572489 . | Open in Read by QxMD
  12. Brown SGA, Ball EL, Perrin K, et al. Conservative versus Interventional Treatment for Spontaneous Pneumothorax. N Engl J Med. 2020; 382 (5): p.405-415. doi: 10.1056/nejmoa1910775 . | Open in Read by QxMD
  13. Kelly A-M. Estimating the rate of re-expansion of spontaneous pneumothorax by a formula derived from computed tomography volumetry studies. Emergency Medicine Journal. 2006; 23 (10): p.780-782. doi: 10.1136/emj.2006.037143 . | Open in Read by QxMD
  14. Broaddus VC. Clearing the Air — A Conservative Option for Spontaneous Pneumothorax. N Engl J Med. 2020; 382 (5): p.469-470. doi: 10.1056/nejme1916844 . | Open in Read by QxMD
  15. Yoon J, Sivakumar P, O’Kane K, Ahmed L. A need to reconsider guidelines on management of primary spontaneous pneumothorax?. International Journal of Emergency Medicine. 2017; 10 (1). doi: 10.1186/s12245-017-0135-x . | Open in Read by QxMD
  16. Pasquier M, Hugli O, Carron P-N. Needle Aspiration of Primary Spontaneous Pneumothorax. N Engl J Med. 2013; 368 (19): p.e24. doi: 10.1056/nejmvcm1111468 . | Open in Read by QxMD
  17. American College of Surgeons and the Committee on Trauma. ATLS Advanced Trauma Life Support. American College of Surgeons ; 2018
  18. Britten S, Palmer SH, Snow TM. Needle thoracocentesis in tension pneumothorax: insufficient cannula length and potential failure. Injury. 1996; 27 (5): p.321-322. doi: 10.1016/0020-1383(96)00007-1 . | Open in Read by QxMD
  19. Porcel JM. Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists. Tuberculosis and Respiratory Diseases. 2018; 81 (2): p.106. doi: 10.4046/trd.2017.0107 . | Open in Read by QxMD
  20. Dev SP, Nascimiento B, Simone C, Chien V. Chest-Tube Insertion. N Engl J Med. 2007; 357 (15): p.e15. doi: 10.1056/nejmvcm071974 . | Open in Read by QxMD
  21. Laws D. BTS guidelines for the insertion of a chest drain. Thorax. 2003; 58 (90002): p.53ii-59. doi: 10.1136/thorax.58.suppl_2.ii53 . | Open in Read by QxMD
  22. Leech C, Porter K, Steyn R, et al. The pre-hospital management of life-threatening chest injuries: A consensus statement from the Faculty of Pre-Hospital Care, Royal College of Surgeons of Edinburgh. Trauma. 2016; 19 (1): p.54-62. doi: 10.1177/1460408616664553 . | Open in Read by QxMD
  23. Tschopp J-M, Bintcliffe O, Astoul P, et al. ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax. European Respiratory Journal. 2015; 46 (2): p.321-335. doi: 10.1183/09031936.00219214 . | Open in Read by QxMD
  24. Olesen WH, Titlestad IL, Andersen PE, Lindahl-Jacobsen R, Licht PB. Incidence of primary spontaneous pneumothorax: a validated, register-based nationwide study.. ERJ open research. 2019; 5 (2). doi: 10.1183/23120541.00022-2019 . | Open in Read by QxMD
  25. Paoloni R. Management and outcome of spontaneous pneumothoraces at three urban EDs. Emergency Medicine Australasia. 2007; 19 (5): p.449-457. doi: 10.1111/j.1742-6723.2007.01011.x . | Open in Read by QxMD
  26. Noppen M, De Keukeleire T. Pneumothorax. Respiration. 2008; 76 (2): p.121-127. doi: 10.1159/000135932 . | Open in Read by QxMD
  27. Herold G. Internal Medicine. Herold G ; 2014
  28. Shankar PS . Subcutaneous Emphysema From Bronchocavitary Subcutaneous Fistula. Lung India. 2008; 25 (2): p.73-74. doi: 10.4103/0970-2113.44123 . | Open in Read by QxMD
  29. Agabegi SS, Agabegi ED. Step-Up To Medicine. Lippincott Williams & Wilkins ; 2013