Superior Mesenteric Artery Syndrome

Abstract

Purpose: Superior Mesenteric Artery syndrome (SMAS), mesenteric duodenal compression or Wilkie's syndrome is an uncommon condition characterized by the compression of third segment of duodenum between superior mesenteric artery and aorta Methods: Presentation 32 year old female presented with severe dull nonradiating epigastric abdominal pain. Pain was intermittent with worsening in supine position and relief with sitting. There was associated nausea, bilious vomiting, fullness and early satiety. She denied altered bowel habits, hemetemesis, hematochezia, dysmenorrhea, vaginal or urinary symptoms. She reported multiple episodes of similar pain in the past one year and had a significant weight loss of about 40 pounds in the same time period. Past medical history was significant for depression. Examination showed a BMI of 18 and remarkable epigastric tenderness without guarding or rebound CBC, BMP, LFTs, amylase, lipase and urine analysis were unremarkable. Upper GI series showed mild proximal dilation of the duodenum. Endoscopy was unremarkable. CT abdomen and MRA: Figure.Figure: MRA & CT abdomen with contrast showing SMA- aorta angle of 20 degrees and aorto-mesenteric distance of 7 mmResults: SMAS is diagnosed based on intermittent abdominal pain with positional variation, nausea, vomiting and rapid weight loss after exclusion of other conditions. Findings on CT and MRA further support the diagnosis. Conclusion: SMA syndrome results from reduction in the aortomesenteric angle (normal 25–60 degrees) and distance between SMA and aorta (normal 10–28 mm) resulting in compression of third portion of duodenum between SMA anteriorly and aorta posteriorly with concurrent duodenal dilation. It is common in females and subjects with low BMI. Asthenic body habitus and depletion of aortomesenteric fat from rapid weightloss could have contributed to duodenal compression and clinical spectrum in our patient. Treatment is conservative and includes nutritional support. For refractory cases surgical options include duodenojejunostomy or transposition of third part of duodenum. Given the minor degree of duodenal stenosis, our patient responded to conservative measures with weight gain and symptom relief. Endoscopic and conventional radiological investigations of these cases may be normal findings are transitory. Diagnosis may easily be overlooked if investigations are performed between manifest periods. High index of suspicion is needed for this potentially treatable condition.