CT Case 029

There is a large right sided pneumothorax (taking up the entire right hemithorax).

There are radiological features of tension, namely;

• mediastinum displaced to the left
• right hemidiaphragm is depressed
• increased rib spacing on the right

Normally such patients would present with severe respiratory distress and haemodynamic instability.

This patient only had mild symptoms, suggesting an acute on chronic presentation.

A pigtail catheter was inserted and the next day a CT chest was performed for further investigation of recurrent pneumothorax.

There is persistent right sided pneumothorax (only partially resolved compared to the CXR pre-pigtail catheter insertion).

The mediastinum is still slightly displaced to the left.

There is subcutaneous emphysema along the right thoracic wall.

The CT confirmed correct catheter position without kinking of the catheter.

There is upper lobe para-septal emphysema (smoking related lung disease).

There are also patchy areas of consolidation in both left and right lungs.

The combination of emphysematous changes in the lung as well as prolonged high-pressure breath holding manoeuvres during marijuana inhalation puts marijuana smokers at high risk of barotrauma -> resulting in pneumothorax, pneumomediastinum and subcutaneous emphysema.

Bong or pipe use also puts patients at risk of atypical infections (such as pseudomonas and aspergillus).

Outcome

This patient was treated with antibiotics for an atypical pneumonia. His lung eventually did re-expand although was slow to do so. The persistent collapse is likely present due to a combination of the underlying pneumonia as well as chronic collapse from recurrent pneumothorax.

If we see a persistent pneumothorax there are a few critical causes that need to be considered;

• Misplaced catheter
• Kinked catheter
• Bronchopleural fistula (very important cause to exclude – clinically this will be apparent due to persistent air leak despite correct catheter placement)