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Study Guide ​


  • A disease defined as the accumulation of air in the pleural space leading to pulmonary collapse.



  • Spontaneous pneumothorax is commonest in young adult males:

  • The M-to-F ratio is 6: 1.

  • Primary Spontaneous Pneumothorax (PSP) has an incidence of 7.4 to 18 cases among males and 1.2 to 6 cases among female per 100,000 populations each year.

  • The general incidence of secondary spontaneous pneumothorax (SSP)  is almost similar to that of PSP. 

Causes and Risk factors:


  • More common in tall, thin young males because of apical subpleural blebs rupture.


  • Most commonly COPD and TB; also seen in asthma, pulmonary infarcts, lung abscess, bronchogenic carcinoma, and all forms of fibrotic and cystic lung disease.

  • More threatening , due to lack of pulmonary reserve.



  • Iatrogenic: secondary to transthoracic and trans-bronchial biopsy, central venous catheterization, pleural biopsy, thoracentesis.

  • Non-iatrogenic: secondary to blunt or penetrating chest injury.


  • The pressure in the pleural space is negative with respect to the atmospheric pressure and the alveolar pressure. If there is a communication either between the alveoli and the pleural space or between the outside of the thoracic cavity and the pleural space, air will continue to enter the pleural space.

  • The increase in the pleural pressure will result in both a hyperexpanded hemithorax and a collapsed lung. 

  • Because the alveolar pressure become very positive resulting in high/positive pleural pressure, producing a tension pneumothorax.

The main physiological consequences of pneumothorax are a decrease in the vital capacity of the lung and in PaO2. Total lung capacity, functional residual capacity and diffusing capacity are also decreased but less than vital capacity.

Sign & Symptoms:

  • Sudden onset of unilateral chest pain on inspiration and progressively increasing dyspnea.

  • Patient with large pneumothorax may develop pallor, tachycardia, and cough.

P-THORAX summaries the presentation of pneumothorax:

  • Pleuritic chest pain

  • Tracheal deviation

  • Hyper-resonance on percussion. 

  • Onset is sudden

  • Reduced breath sounds unilaterally. 

  • Absent fremitus

  • X-ray shows lung collapse


  • The diagnosis is done clinically due to emergent need of treatment.
  • Chest X-ray:
    • Reveals visible visceral pleural edge as a very thin, sharp white line with no lung markings are seen peripheral to this line.
    • The peripheral space is radiolucent compared to adjacent lung.

The lung may completely collapse and the mediastinum should not shift away from the pneumothorax unless a tension pneumothorax is present.



  • Tension pneumothorax:

    • Immediate decompression by large bore needle in the 2nd intercostal space mid-axillary line. 

    • Followed by chest tube placement under water seal. 

  • For small pneumothoraces:

    • Supplemental O2 until it resolves spontaneously.

  • Large symptomatic pneumothoraces:

    • Chest tube placement under water seal. 


Spontaneous pnemothorax has a recurrence rate of 50% in 2 years.


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  •, (2016). Prevalence and Incidence of Pneumothorax - [online] Available at: [Accessed 13 Feb. 2016].

  • Noppen, M. (2010). Spontaneous pneumothorax: epidemiology, pathophysiology and cause. European Respiratory Review, 19(117), pp.217-219.

  • Agabegi S, Agabegi E, Ring A. Step-up to medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2013.

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  • EMR - EMT - Medical [Internet]. Pinterest. 2016 [cited 4 April 2016]. Available from: (Figure 1).

  • 354. Iñarritu J. You should never take this chest x-ray | Unbounded Medicine [Internet]. 2005 [cited 4 April 2016]. Available from: (Figure 2). 

​Written by: Abdulrahman Alqahtani                                                     

Reviewed by: Salwa AlMakhdob
                               Areej Madani 

Web Publisher : Adel Yasky                                                                        

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