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Rare Case of Superior Mesenteric Artery Syndrome: A Story of Missed Diagnosis


Sharma, Aakanksha MD1; Wahab, Abdul MBBS2; Salama, Amr MD3; Disalle, Michael MD1

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American Journal of Gastroenterology: October 2017 - Volume 112 - Issue - p S1369-S1370
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Abdominal pain continues to pose the diagnostic challenges for the physicians. Low threshold of suspicion for uncommon etiologies is important to make a timely diagnosis and treatment .We present a rare case of SMA syndrome in an elderly male presenting with abdominal pain. 65 years old male with no PMH, presented with abdominal pain, nausea and vomiting for 7 days. He denied weight loss. On physical exam, he was thin with BMI of 18.9. Lab work-up revealed BUN 71 mg/dl, Cr 3.7mg/dl and Na 133 mmol/L. He was treated with intravenous fluids for presumed diagnosis of gastroenteritis. After 4 days of hospitalization, he continued to have nausea and vomiting. Ultrasound of abdomen showed fluid filled dilated stomach, followed by CT contrast abdomen revealing dilated stomach and duodenum up to 3rd part with abrupt narrowing as it crossed the midline. Aortomesenteric angle (AMA) of approximately 9° was noted, suggesting the diagnosis of Superior mesenric artery syndrome. Nasogastric tube was placed for decompression. Upper GI endoscopy ruled out other mechanical causes of obstruction.On day 7 NGT was removed and he was discharged home to continue mechanical soft diet to gain weight. Unfortunately, 3 days later he was readmitted with similar complaints. This time he had gastrojejunostomy tube placement to try tube feeding for at least 3 months to gain weight before considering surgical treatment options. SMAS is a rare cause of abdominal pain. True incidence of SMAS is unknown. SMA originates from aorta at level of L1-2 and extends anteroinferiorly into mesentery at an angle with aorta known as aortomesenteric angle (AMA) which normally varies from 28°-65. SMAS is characterized by acute AMA, compressing 3rd part of duodenum between aorta and SMA. Several factors are listed which have an effect on AMA. The most common is significant weight loss, most commonly seen in severe debilitating illnesses, such as malignancy, AIDS, trauma and burns. Congenital short ligament of Treitz has also been reported as one of the causes. Symptoms usually include early satiety, nausea, vomiting and epigastric pain. Contrast CT scan is useful in the diagnosis. Upper GI endoscopy may be necessary to exclude mechanical causes of duodenal obstruction. Initially treatment is conservative with fluid and electrolyte resuscitation, gastric decompression and nutritional support to gain weight. If conservative therapy fails surgical treatment is indicated to bypass the obstruction.

CT contrast abdomen showing acute aortomesenteric angle at 9 degrees.
Upper GI endoscopy revealed extrinsic duodenal compression without intra luminal pathology.
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