Radiological abnormality in case of tension pneumothorax

A 23-y man with well past health, presented with sudden onset of left sided chest pain and shortness of breath, This pain was sharp in nature and more severe on inspiration. Physical examination showed decreased air entry in the left upper chest which was hyperresonant on percussion. Laboratory investigations were essentially normal. A CXR was performed for further evaluation .

Large left pneumothorax with mediastinal shift to the right. Note the collapsed left lung (arrows) and the hyperlucent left hemithorax.

(1) The radiological abnormality that can be identified :
- Hyperlucent zone devoid of vascular marking in periphery of left hemithorax.
- Shift of midline to the right.

(2) So; the most likely diagnosis is left tension pneumothorax
Note the radiological features of tension pneumothorax seen in this
patient include:
- Contralateral mediastinal shift
- Depression of ipsilateral hemidiaphragm
- Compressive atelectasis of adjacent normal lung
All of the above radiological signs indicate the presence of significant increased intra-thoracic pressure in tension pneumothorax which necessitates urgent treatment.

Notes:

* The diagnosis of pneumothorax is confirmed by erect chest radiograph in full expiration.

* The absence of vascular markings in the periphery of the left hemithorax is due to air in the pleural cavity and not in the lung.

* Role of imaging in patients with pneumothorax:
1. Confi rm the clinical diagnosis
2. Assess extent of pneumothorax
3. Detect signs of tension pneumothorax
4. Follow-up examination to monitor resolution of pneumothorax after drainage