Pneumothorax

Pneumothorax is the presence of gas in pleural space

Primary spontaneous pneumothorax
- occurs without antecedent trauma to thorax and in the absence of underlyign lung disease, usually due to rupture of apical pleural blebs.
- occurs almost exclusively in smokers (lifetime risk of 12% in smoker as compared to 0.1% in non smoker)
- initial recommended treatment : simple aspiration
- supplementary high flow oxygen should be given to reduce the total pressure of gases in pleural capillaries by reducing the partial pressure of nitrogen, thus increase the pressure gradient between pleural capillaries and pleural cavity thereby increasing absorption of air from pleural cavity
- strong emphasis should be placed on the relationship between the recurrence of pneumothorax and smoking in an effort to encourage patient to stop smoking (recurrence rate of 54% within first 4 years)



Secondary pneumothorax
- due to chronic obstructive pulmonary disease
- clinical symptoms associated with secondary pneumothoraces are more severe than those associated with primary spontaneous pneumothoraces (lack of pulmonary reserve)



Traumatic pneumothorax
- penetrating or non-penetrating chest trauma
- should be treated with tube thoracostomy unless they are very small

Tension pneumothorax
- positive pleural pressure is life threatening because ventilation is severely compromised and positive pressure is transmitted to mediastinum, resulting in decreased venous return to the heart and reduced cardiac output
- large bore needle should be inserted into pleural space through the second anterior intercostal space

Size of pneumothorax depending on the visible rim between lung margin and chest wall
- small < 2cm (less than 50% of hemithorax)
- large ≥ 2cm (more than 50%)



Pneumothoraces which failed to respond within 48 hours should be referred to a respiratory physician. In case of persistent air leak or failure of lung to re-expand, the managing respiratory specialist should seek and early (3-5days) thoracic surgical opinion

Patients discharged without intervention should avoid air travel until a chest radiograph confirmed the resolution of pneumothorax. Diving should be permanently avoided after pneumothorax unless patient had bilateral surgical pleurectomy

Source: BTS guidelines for the management of spontaneous pneumothorax
             18th edition Harrison's principle of internal medicine