From the Guidelines
Pneumothorax is caused by air accumulating in the pleural space between the lung and chest wall, leading to partial or complete lung collapse, with the most common causes including trauma, spontaneous rupture of blebs or bullae, underlying lung diseases, mechanical ventilation, and certain activities that increase intrathoracic pressure 1.
Causes of Pneumothorax
The causes of pneumothorax can be categorized into:
- Traumatic: resulting from injuries such as rib fractures, penetrating chest injuries, or iatrogenic injury during medical procedures like central line placement
- Spontaneous: occurring without any apparent cause, further divided into primary (in otherwise healthy individuals) and secondary (as a complication of existing lung disease)
- Iatrogenic: resulting from medical procedures, with the incidence being high and outnumbering spontaneous pneumothoraces in several large review series 1
Mechanism and Symptoms
The fundamental mechanism involves disruption of the pleural membrane, allowing air to enter the pleural space and destroy the negative pressure that normally keeps the lung expanded. This air accumulation prevents normal lung expansion during breathing, causing symptoms like:
- Sudden chest pain
- Shortness of breath
- In severe cases, respiratory distress or cardiopulmonary compromise
Risk Factors
Certain factors increase the risk of developing pneumothorax, including:
- Smoking, which plays a significant role in the development of primary pneumothorax, with the lifetime risk being as much as 12% in healthy smoking men compared to 0.1% in non-smoking men 1
- Underlying lung diseases, such as COPD, cystic fibrosis, and interstitial lung diseases
- Mechanical ventilation with high pressures
- Activities that increase intrathoracic pressure, like scuba diving or flying at high altitudes
Management
The management of pneumothorax depends on the severity and underlying cause, with options including:
- Simple aspiration, recommended as first-line treatment for primary pneumothoraces requiring intervention 1
- Tube drainage, recommended for large secondary pneumothoraces or when simple aspiration is not successful
- Surgical intervention, in cases where other treatments fail or are not appropriate It is essential to address the underlying cause and manage any related conditions to prevent recurrence and improve outcomes. The most recent guideline from the British Thoracic Society emphasizes the importance of simple aspiration as a first-line treatment for primary pneumothoraces and highlights the need for individualized management approaches based on the severity and underlying cause of the pneumothorax 1.
From the Research
Pneumothorax Causes
- Pneumothorax is defined as air in the pleural space and is classified as spontaneous or nonspontaneous (traumatic) 2, 3
- Traumatic pneumothorax is a common pathology identified in the emergency department, often found in up to 50% of severe polytrauma patients with chest injury 3
- Findings associated with pneumothorax include dyspnea, chest pain, tachypnea, and absent breath sounds on lung auscultation 3
- Pneumothorax can occur secondary to an underlying localized or diffuse parenchymal lung disease 4
- Histopathologic findings suggest that a ruptured bulla or bleb can cause pneumothorax, especially in smokers 4
Diagnosis and Management
- Traditional management calls for chest x-ray (CXR) diagnosis and large-bore tube thoracostomy, although recent literature supports the efficacy of lung ultrasound (US) and more conservative approaches 2
- Lung US has proven to be a potentially more useful tool in the detection of pneumothorax in the trauma bay compared with CXR, and has the potential to become the new gold standard for diagnosing traumatic pneumothorax 2
- Computed tomography remains the ultimate gold standard, although in the setting of trauma, its utility lies more in confirming the presence and measuring the size of a pneumothorax 2
- Patients with traumatic pneumothorax are typically treated with needle decompression or tube thoracostomy, but recent literature has found that many patients can be managed conservatively via observation, or with a smaller thoracostomy such as a percutaneous pigtail catheter rather than a larger chest tube 2, 3