Hydropneumothorax verses Simple Pneumothorax

Three cases are presented to compare and contrast the radiographic findings in hydropneumothorax versus simple pleural effusion. The first case is of a 72-year-old man with metastatic colon cancer presenting with worsening shortness of breath. Post-thoracentesis chest radiographs Fig 1 and CT Fig 2 demonstrate a hydropneumothorax. The second case is of a 67 year-old male with non-small cell lung carcinoma who developed a hydropneumothorax following percutaneous drain placement Fig 3 and 4. A third case is presented of a 65 year-old male with a left-sided pleural effusion Fig 5 for comparison. Hydropneumothorax consists of both free fluid and air within the pleural space with common etiologies being iatrogenic post-thoracentesis, presence of gas forming organisms, and trauma. Simple pleural effusions consist of fluid only within the pleural space and are a result of increased hydrostatic pressure in the pulmonary vasculature, decreased oncotic pressure, or a combination of the two. The distinction between simple effusion and hydropneumothorax is usually straightforward and important in order to apply appropriate therapy. Also, detection of an air-fluid level could be the only indicator of a pneumothorax.