• Clinical science
  • Clinician



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.



Spontaneous pneumothorax

Traumatic pneumothorax

Any type of pneumothorax may lead to tension pneumothorax.



Clinical features

Patients range from being asymptomatic to having features of hemodynamic compromise. [4]

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


General principles [6]

  • 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 [4][6]

Ultrasound [7]

  • Indications
    • Trauma (eFAST)
    • Quick bedside assessment
  • Supportive findings [12]
    • Absence of pleural sliding
    • Absence of B-lines
    • Barcode sign instead of seashore sign in M-mode
    • Combination of prominent A-lines and absent B-lines

Chest CT [4]

  • 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 [6]
  • Interpleural distance at the level of the lung hilus [4]
  • Collins method: Calculated pneumothorax size in percent of hemithorax [13][14]
    • 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.

Differential diagnoses

See differential diagnoses of acute chest pain and differential diagnoses of dyspnea.

The differential diagnoses listed here are not exhaustive.


Approach [4][6]

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 [6]

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 [4][5][6]

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

Primary spontaneous pneumothorax (stable patient) [4][6]

  • Apex-to-cupula distance < 3 cm
    • Usually resolves spontaneously within a few days (∼ 10 days) [15]
    • Serial follow-up with repeat chest x-ray
      • Repeat CXR after observation for 3–6 hours to exclude progression prior to discharge.
      • Consider outpatient management with follow-up within 2 days. [6][4]
  • Apex-to-cupula distance ≥ 3 cm
    • Chest tube placement typically recommended
    • Consider conservative management in otherwise healthy patients without respiratory distress and no progress in repeat CXR after 4 hours. [14][16][17]
    • Needle aspiration may also be considered. [4]

Secondary spontaneous pneumothorax, age > 50 years, or history of smoking (stable patient) [4][6]

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
    • Indication: tension pneumothorax
    • Procedure:
      • Immediate insertion of a large-bore needle into the second intercostal space along the midclavicular line
      • Typically followed by the insertion of a chest tube
      • If initial decompression fails, consider using a longer needle (especially in muscular/adipose patients) [4][18]
  • Chest tube placement [19]
  • Surgery
    • Indications [4]
      • Recurrent ipsilateral pneumothorax episodes
      • Bilateral or contralateral pneumothorax
      • Persistent air leak or insufficient lung re-expansion for 5–7 days despite chest tube placement
      • Extensive underlying lung disease
      • High-risk occupation (e.g., pilots)
    • Procedures
      • Video-assisted thoracoscopic surgery (VATS)
      • Thoracotomy if necessary
    • 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) [4]
        • Chemical/pharmacological (administration into the pleural space): talc powder , doxycycline, minocycline [4][6]

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

Acute management checklist

Acute management checklist for tension pneumothorax [5][20]

Acute management checklist for spontaneous pneumothorax [4][6][20]

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)

  • Small pneumothorax (< 3 cm apex-to-cupola distance)
    • Monitor closely.
    • Order repeat CXR in 3–6 hours.
  • Large pneumothorax (≥ 3 cm apex-to-cupola distance)

Secondary spontaneous pneumothorax (stable patient)

  • Small pneumothorax (< 3 cm apex-to-cupola distance)
    • Admission with monitoring for 24 hours
    • Consider chest tube insertion to water seal or Heimlich valve until lung re-expands.
    • Order repeat CXR after chest tube insertion.
    • Consult thoracic surgery.
  • Large pneumothorax (≥ 3 cm apex-to-cupola distance)
    • Chest tube insertion to water seal or Heimlich valve until lung re-expands
    • Order repeat CXR after chest tube insertion.
    • Consider ICU transfer.
    • Consult thoracic surgery.



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

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last updated 11/16/2020
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