Purpose or Case Report: Superior mesenteric artery (SMA) syndrome, or Wilkie’s syndrome, is an obscure condition in which an acute angulation between the aorta and SMA leads to compression of the third part of the duodenum. Subsequently, patients typically present with a constellation of gastrointestinal findings that closely resemble small bowel obstruction, early satiety, and anorexia. SMA syndrome is most often observed in the setting of rapid weight loss, wasting conditions, and corrective spinal surgeries, where a decrease in retroperitoneal fat diminishes the cushion between the aorta and SMA, causing vascular compression of the duodenum. Diagnosis of SMA syndrome is one of exclusion and is based on the combination of highly suspicious clinical findings and confirmatory diagnostic imaging evidence of obstruction. Upper GI Fluoroscopy can demonstrate a dilated first and second portion of the duodenum, with compression of the third portion, and delayed passage of contrast past midline. Ultrasound and computed tomography (CT)/magnetic resonance imaging (MRI) enable measurement of the aortomesenteric angle and distance, with normal values ranging from 25-60° and 10-28mm, respectively, and values indicative of SMA syndrome ranging from 6-15° and 2-8mm, respectively.
We present a classic case of SMA syndrome in a 15-year-old patient. The patient presented with clinical symptoms consisting of scoliosis, chronic nausea and vomiting, weight loss, and anorexia. The patient then underwent Upper GI Fluoroscopy which demonstrated duodenal dilatation and delayed contrast transit past midline, achieved only after prolonged decubitus and prone positioning. Subsequently, abdominal ultrasound demonstrated an aortomesenteric angle of 10-18° and an aortomesenteric distance of 5 mm. Lastly, abdominal MRI demonstrated an aortomesenteric angle of 15° and an aortomesenteric distance of 3 mm, corroborating the ultrasound findings and confirming the diagnosis of SMA syndrome. The patient was initiated on nutritional support and at most recent follow-up was responding well to conservative treatments.
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Conclusions: Knowledge of the imaging findings of this rare disorder can provide early diagnostic capabilities and lead to more effective treatment plans.