2692 Dunbar Syndrome: A Rare Cause of Abdominal Pain

Abstract

INTRODUCTION: Dunbar Syndrome, also known as median arcuate ligament syndrome (MALS), is a rare condition with a reported incidence of 2 per 100,000. It is characterized by an extrinsic compression of the celiac trunk, and should be considered when evaluating patients with abdominal pain of unknown etiology. CASE DESCRIPTION/METHODS: A 78 year old female presented with a complaint of epigastric discomfort that was post-prandial in nature, with associated weakness and early satiety. Her symptoms had been persistent for one year. Workup prior to her presentation included a normal nuclear medicine (NM) gastric emptying scan and normal NM hepatobiliary scan with CCK. A detailed history revealed that her pain was particularly worse after eating and was associated with early satiety. Laboratory results on admission were unremarkable. Contrast-enhanced CT scan of the abdomen and pelvis showed external compression and indentation of the superior aspect of the proximal celiac axis with post-stenotic dilation. Further diagnostic evaluation utilized end-inspiratory phase CT angiography of the abdomen, which showed an approximately 1 cm length segment of proximal celiac arterial narrowing, measuring 70% maximally at its origin. She was diagnosed with MALS after review of the CTA reconstructive images which showed moderate external compression of the celiac artery. DISCUSSION: MALS predominantly affects women between the ages of 30 and 50 and is marked by the hallmark feature of postprandial abdominal pain. Other signs and symptoms may include nausea, vomiting, and consequent weight loss from an inability to tolerate oral intake. Symptoms are thought to have both a vascular (mesenteric ischemia) as well as neurogenic component (somatic pain thought to originate from the splanchnic plexus). CT angiography and conventional angiography are considered to be gold standard imaging modalities for Dunbar syndrome. They demonstrate focal stenosis that has a characteristic hooked appearance due to the indentation of the celiac trunk on its superior surface. Imaging for an accurate diagnosis should ideally be performed during the end-inspiratory phase, as indentation of the celiac trunk may be seen normally during expiration. Additional imaging features may include post-stenotic dilation, prominent collateral vessels, and thickening of the median arcuate ligament. Treatment includes endovascular transluminal angioplasty and stent placement, as well as laparoscopic division of the arcuate ligament and resection of the celiac plexus.