Superior mesenteric artery syndrome.

Superior mesenteric artery (SMA) syndrome is an uncommon and potentially fatal cause of small bowel obstruction where the third portion of the duodenum is compressed between the abdominal aorta and the superior mesenteric artery. This is most frequently seen after sudden and significant weight loss, but other etiologies can also cause this duodenal compression. This syndrome can lead to food aversion, poor intake, and weight loss that exacerbate symptoms in a vicious cycle.