Superior Mesenteric Artery Syndrome, Gastroparesis and GERD
Superior mesenteric artery, SMA, syndrome is a rare disorder. Patients with SMA syndrome, like those with gastroparesis and GERD, present with epigastric pain, bloating, nausea, vomiting and early satiety as well as heartburn and food regurgitation. Symptoms are typically exacerbated by food intake.
SMA syndrome is thought to be the result of compression of the third part of the duodenum between the superior mesenteric artery anteriorly and the vertebral column posteriorly. This results in partial or complete obstruction of the third part of the duodenum leading to pain and vomiting. The compression may be secondary to a narrowed aorto-mesenteric angle that typically occurs with significant weight loss and loss of the fat pad which normally separates the SMA from the aorta. Other patients have a genetic predisposition for SMA syndrome. A low take-off of the SMA or short ligament of Treitz may lead to narrowing of the duodenal lumen.
The diagnosis of SMA syndrome is difficult. CT scan finding of narrowed aortomesenteric angle by itself is not enough to confirm the diagnosis. A comprehensive workup including upper endoscopy, gastric emptying study and upper gastrointestinal contrast study must be interpreted in conjunction with patient symptom and presentation. Gastroparesis may be associated with duodeno-paresis and dilated proximal duodenum and may be mistaken for SMA syndrome. The treatment of gastroparesis with a longitudinal gastrectomy largely differs from that of SMA syndrome.
Medical management is the first line treatment for SMA syndrome patients and it entails tube feeding beyond the obstruction. Most patients respond to medical treatment and can maintain their weight after tube feeding is stopped. Patients who fail medical treatment or whose symptoms persist despite weight gain are offered a surgical solution. The most common procedure performed for SMA syndrome is laparoscopic side to side duodeno-jejunostomy. A loop of jejunum 30 cm distal to the ligament of Treitz is typically anastomosed to the second portion of the duodenum in a retrocolic fashion. The success rate reported in the literature in various case series varies from 75 to 100%. The surgery is minimally invasive, safe and associated with low complication rate.