- Pneumothorax is the presence of air within the pleural space
- Due to disruption of parietal, visceral or mediastinal pleura
- May also occur from spontaneous rupture of subpleural bleb
- A tension pneumothorax occurs when pleura form a one-way flap valve
- Tension pneumothorax is a medical emergency
Classification
- Spontaneous pneumothorax
- Primary - no identifiable pathology
- Secondary - underlying pulmonary disorder
- Catamenial
- Traumatic
- Blunt or penetrating thoracic trauma
- Iatrogenic
- Postoperative
- Mechanical ventilation
- Thoracocentesis
- Central venous cannulation
Primary spontaneous pneumothorax
- Usually occurs in young healthy adult men
- 85% patients are less than 40 years old
- Male : female ratio is 6:1
- Bilateral in 10% of cases
- Occurs as result of rupture of an acquired subpleural bleb
- Blebs have no epithelial lining and arise from rupture of the alveolar wall
- Apical blebs found in 85% of patients undergoing thoracotomy
- Frequency of spontaneous pneumothorax increases after each episode
- Most recurrences occur within 2 years of the initial episode
Secondary spontaneous pneumothorax
- Accounts for 10-20% of spontaneous pneumothoraces
- can be due to:
- Chronic obstructive pulmonary disease with bulla formation
- Interstitial lung disease
- Primary and metastatic neoplasms
- Ehlers-Danlos syndrome
- Marfan's syndrome
Traumatic pneumothorax
- Can result from either blunt or penetrating trauma
- Tracheobronchial and oesophageal injuries can cause both mediastinal emphysema and pneumothorax
- Iatrogenic pneumothorax is common
- Occurs after
- Pneumonectomy
- Thoracocentesis
- High-pressure mechanical ventilation
- Subclavian venous cannulation
Clinical features
- Predominant symptom is acute pleuritic chest pain
- Dyspnoea results form pulmonary compression
- Symptoms are proportional to the size of the pneumothorax
- Also depend on the degree of pulmonary reserve
- Physical signs include
- Tachypnoea
- Increased resonance
- Absent breath sounds
- In a tension pneumothorax
- The patient is hypotensive with acute respiratory distress
- The trachea may be shifted away from the affected side
- Neck veins may be engorged
- Diagnosis can be confirmed with a chest x-ray
Management
Spontaneous pneumothorax
- Depends symptoms and the radiological size of the pneumothorax
- Small asymptomatic pneumothoraces (<20%) may simply be followed with serial chest x-rays
- If drainage required a chest drain should be inserted
- Through the 5th intercostal space
- Just above the upper border of the rib
- Blunt insertion (rather than using the trocar) should be used
- Position should be checked with a chest x-ray
- Should be connected to an underwater seal placed below the level of the patient
Tension pneumothorax
- Prophylactic chest drains should be inserted in patients with rib fractures prior to ventilation
- Tension pneumothorax requires immediate needle aspiration
- Inserted anteriorly through the 2nd intercostal space
- Chest drain can then be inserted
Picture provided by Abid Majeed, Services Hospital, Lahore, Pakistan
Surgery
- Surgery is required for
- Air leak persisting for more than 10 days
- Failure of lung re-expansion
- Recurrent spontaneous pneumothorax
- Surgical options include
- Partial pleurectomy
- Operative abrasion of pleural lining
- Resection of pulmonary bullae
- Poor-risk patients may benefit from chemical pleurodesis with tetracycline
Bibliography
Baumann M H, Strange C. Treatment of spontaneous pneumothorax. Chest 1997;
112: 789-804. |