Pain in the right upper abdomen
The gallstones were the clue to the problems. A day before the ultrasound examination an attempt was made to perform an ERCP that had caused a duodenal perforation which caused the pneumoretroperitoneum.
References
Nürnberg D, Mauch M, Spengler J, Holle A, Pannwitz H, Seitz KSonographical diagnosis of pneumoretroperitoneum as a result of retroperitoneal perforation]
Ultraschall Med. 2007 Dec;28(6):612-21.