Superior mesenteric artery syndrome in a 16-year-old with bilious emesis.

Superior mesenteric artery (SMA) syndrome describes vascular compression of the third portion of the duodenum and presents with nausea, postprandial vomiting, and epigastric abdominal pain. The syndrome is rare and may be missed if appropriate radiologic studies are not performed or the clinical presentation is atypical. The clinical contexts in which SMA syndrome develops usually involve rapid weight loss, alterations in spine anatomy, or external increases in abdominal pressure. Diagnostic methods for identifying duodenal obstruction by the SMA include upper gastrointestinal barium contrast studies, computed tomography scans, or angiography of the aorta with either contrast or magnetic resonance angiography. Medical therapy relies upon nutritional rehabilitation with either jejunal tube feedings or parenteral nutrition until weight gain results in relief of the obstruction. In instances where this approach fails, surgical correction is necessary, most often with laparoscopic duodenojejunostomy.