Hydropneumothorax

Hydropneumothorax implies presence of both air and fluid in the pleural space ( i.e. between two layers of pleura). An erect chest xray will show air fluid level.The horizontal fluid level is usually well defined and extends across the whole length of hemithorax.

Causes

 * Iatrogenic: Introduction of air during pleural fluid aspiration in effusion.
 * Presence of gas forming organism.
 * Trauma