Duodenal obstruction from superior mesenteric artery syndrome with nutcracker phenomenon in an adolescent: a case...

Superior mesenteric artery (SMA) syndrome is a rare cause of duodenal obstruction. Its diagnosis is often delayed due to nonspecific symptoms that mimic common functional gastrointestinal disorders. This case highlights the diagnostic challenge and the critical role of imaging, further complicated by an incidental, anatomically related finding.

A 13-year-old male presented with a 2-month history of post-prandial vomiting, epigastric pain relieved by a prone position, and unintentional weight loss of 9.3% of total body weight, having previously been treated unsuccessfully for functional dyspepsia. A contrast-enhanced abdominal CT scan revealed a characteristic reduction in the aortomesenteric angle to 18.7° and distance to 4.62 mm, confirming SMA syndrome. Concurrently, the scan demonstrated left renal vein compression with a ratio of ~2.9, consistent with the Nutcracker phenomenon, for which the patient was asymptomatic. He underwent a successful open side-to-side duodenojejunostomy with an uneventful recovery. At 4-month follow-up, the patient remained asymptomatic with no urologic sequelae.

This case illustrates the shared anatomic basis of SMA syndrome and Nutcracker anatomy within a narrow aortomesenteric compartment. It underscores the necessity of a comprehensive cross-sectional imaging review to identify dual compressions. While surgical intervention (duodenojejunostomy) is definitive for symptomatic SMA syndrome, asymptomatic Nutcracker findings warrant surveillance but not immediate intervention.

SMA syndrome should be considered in adolescents with chronic, positional vomiting. Radiologic evaluation must extend beyond the duodenum to assess for associated vascular compression. This case reinforces the importance of a holistic imaging approach for accurate diagnosis and appropriate management.