From the Guidelines
Pneumothorax and tension pneumothorax can be differentiated on chest X-ray (CXR) by the presence of mediastinal shift, depression of the ipsilateral diaphragm, and widening of intercostal spaces in tension pneumothorax, which are not typically seen in simple pneumothorax. The key difference between pneumothorax and tension pneumothorax is the presence of a one-way valve mechanism in tension pneumothorax, which allows air to enter but not exit the pleural space, causing progressive pressure buildup and displacement of mediastinal structures 1.
Characteristics of Pneumothorax and Tension Pneumothorax
- Pneumothorax: visible pleural line with absence of lung markings peripheral to this line, indicating air in the pleural space, with the lung appearing collapsed toward the hilum and increased radiolucency in the affected hemithorax
- Tension Pneumothorax: same findings as pneumothorax plus mediastinal shift away from the affected side, depression of the ipsilateral diaphragm, and widening of intercostal spaces
Clinical Implications
The development of tension pneumothorax is often heralded by a sudden deterioration in the cardiopulmonary status of the patient, with symptoms including rapid labored respiration, cyanosis, sweating, and tachycardia 1. Immediate needle decompression followed by chest tube placement is required for tension pneumothorax, whereas simple pneumothorax management depends on size and symptoms. It is essential to suspect tension pneumothorax in patients who suddenly deteriorate or develop cardiac arrest, particularly those on mechanical ventilators or nasal non-invasive ventilation 1.
From the Research
Difference between Pneumothorax and Tension Pneumothorax on Chest X-ray (CXR)
- Pneumothorax is defined as air in the pleural space and can be classified as spontaneous or nonspontaneous (traumatic) 2
- Tension pneumothorax is a life-threatening condition that requires immediate diagnosis and intervention, characterized by a large pneumothorax with mediastinal shift and hypotension 3, 4
- On CXR, pneumothorax appears as a visible edge of the lung away from the chest wall, while tension pneumothorax shows a larger pneumothorax with mediastinal shift and possible compression of the contralateral lung 3, 4
Diagnostic Challenges
- Diagnosing tension pneumothorax can be challenging due to non-specific symptoms and rarity of its occurrence during surgery 3
- Clinical correlation with catheter length is crucial for successful needle thoracostomy in tension pneumothorax 5
- Lung ultrasound (US) has proven to be a potentially more useful tool in the detection of pneumothorax in the trauma bay compared with CXR 2
Management
- Traditional management of traumatic pneumothorax calls for CXR diagnosis and large-bore tube thoracostomy, although recent literature supports the efficacy of lung US and more conservative approaches 2
- Needle thoracostomy is an effective treatment for tension pneumothorax, but catheter length is crucial for success 6, 5
- Modern management of traumatic pneumothorax is shifting toward use of US for diagnosis and more conservative management practices (smaller catheters or observation) 2