An Unusual Cause of Duodenal Obstruction

Introduction: Superior mesenteric artery (SMA) compression of the duodenum is well described, but duodenal obstruction caused by extrinsic compression from an abdominal aortic aneurysm (AAA) occurs rarely. Report: This case report describes a patient who presented with nausea and bilious vomiting and was found to have SMA syndrome due to an 8.6 cm suprarenal AAA. He declined an open aneurysm repair, but elected to have an enteric bypass procedure for symptomatic relief. Discussion: SMA syndrome is caused by compression of the third portion of the duodenum between the aorta and the SMA, resulting in complete or partial duodenal obstruction. Only 22 cases of SMA syndrome caused by an AAA have been reported in the literature; usually there is an inflammatory process involved with the aneurysm or there is an infrarenal aortic neck. Definitive treatment consists of open aneurysm repair or decompress the aneurysm sac; other options are enteric bypass, duodenal transposition or duodenal mobilization and caudal displacement (Strong's procedure).