SUPERIOR MESENTERIC ARTERY SYNDROME MASQUERADING AS GASTRIC OUTLET OBSTRUCTION: A CASE REPORT HIGHLIGHTING THE IMPORTANCE OF CONSIDERING RARE VASCULAR CAUSES OF CHRONIC VOMITING

Abstract

Background: Superior mesenteric artery (SMA) syndrome is an uncommon cause of upper gastrointestinal obstruction resulting from compression of the third part of the duodenum between the SMA and the aorta, owing to a narrowed aortomesenteric angle and distance. It is frequently misdiagnosed because its presentation mimics more common conditions such as peptic ulcer disease and gastric malignancy. Case Presentation: We report a 55-year-old male farmer who presented with a four-month history of postprandial upper abdominal pain, self-induced vomiting of partially digested food 10–15 minutes after meals, and unintentional weight loss of 20 kg over one month. Examination revealed a cachectic patient (BMI 16.1 kg/m²) with a scaphoid, non-distended abdomen and a positive succussion splash. Contrast studies and contrast-enhanced computed tomography (CECT) of the abdomen demonstrated marked dilatation of the duodenum up to the duodenojejunal flexure with an abrupt transition, a reduced aortomesenteric distance of 7 mm, and a narrowed aortomesenteric angle of 20 degrees, confirming SMA syndrome. Conclusion: SMA syndrome should be considered in the differential diagnosis of chronic postprandial vomiting associated with significant weight loss, particularly when initial investigations such as ultrasonography and endoscopy are inconclusive. A high index of suspicion combined with targeted cross-sectional imaging is essential for timely diagnosis and management, avoiding unnecessary interventions directed at more common differentials.