Clinical Presentation

A 25-year-old man is found unconscious on the ground and taken to the emergency department.

(A) Upright abdominal radiograph shows pneumoperitoneum manifesting as a thin rim of subdiaphragmatic gas (small arrow). A presumed pulmonary contusion is visible (large arrow). (B) Abdominal radiograph shows a bubbly gas collection in the perirenal space (arrowhead), extending along the inferior margin of the liver (arrow).

Differential Diagnosis

• Traumatic duodenal rupture: This is the most likely diagnosis, given the combination of retroperitoneal gas and pneumoperitoneum. The presumed pulmonary contusion supports the diagnosis by providing evidence of trauma.

• Duodenal rupture from peptic ulcer disease or neoplasm: This can produce identical findings, but the pulmonary finding makes this less likely (see also below).