Diagnosis of Superior Mesenteric Artery Syndrome: the Role of Functional Tests and Radiologic Imaging

Superior mesenteric artery syndrome (SMAS) is a rare condition found in approximately 2.67% of patients hospitalized with suspected duodenal obstruction. The average age of affected individuals is 23 years, with female-to-male ratio of 3:2. SMAS occurs due to compression of the middle third of the horizontal (third) portion of the duodenum between the aorta and the superior mesenteric artery, often developing in the context of rapid and significant weight loss. We present a case of a 32-year-old female patient who, after significant weight reduction and in otherwise good general health, developed complaints of nausea, heartburn, and epigastric pain. During the diagnostic process, differential diagnoses included gastroesophageal reflux disease, peptic ulcer disease, megaduodenum, aberrant pancreatic tissue, neoplasms, and SMAS. To establish the diagnosis, fluoroscopic examination with barium contrast was performed in the prone position to assess the degree of duodenal compression, along with a functional maneuver involving elevation of the upper body while resting on the elbows and knees. Fluoroscopy in the prone position revealed a narrowing of the duodenal lumen at the level of the inferior horizontal portion, from 3.5 to 0.8 cm in diameter over a 3.2 cm segment. The functional maneuver resulted in dilation of the narrowed segment to 3.0 cm, with restoration of evacuatory function. SMAS was confirmed by contrast-enhanced abdominal computed tomography (CT), which demonstrated a reduction in the aortomesenteric angle and distance – from 25° to 6° and from 8 to 2 mm, respectively. It was shown that fluoroscopy with barium contrast and functional testing is an effective diagnostic tool for SMAS. In cases with positive radiographic findings, the diagnosis should be confirmed by contrast-enhanced abdominal CT.