Hydropneumothorax implies presence of both air and fluid in the pleural space ( i.e. between two layers of pleura. An erect chest x-ray will show the air fluid level. The horizontal fluid level is usually well defined and extends across the whole length of hemithorax.
- Iatrogenic: Introduction of air during pleural fluid aspiration in effusion.
- Presence of gas forming organism.
- Thoracic Trauma
This can be remembered by 4 'S'
- Straight line dullness
- Shifting dullness
- Succussion splash
- Sound of coin