Pneumoretroperitoneum.

Pneumoretroperitoneum is rare, but sometimes seen in association with pneumoperitoneum as a result of barotrauma to the lungs. However, there have only been two previous cases of pneumoretroperitoneum without pneumoperitoneum following barotrauma. This case discusses several of the possible mechanisms by which this could occur and what associated signs, especially on chest X-ray, one should look for to confirm the aetiology of gas in the retroperitoneal space.