S2813 Mimicking Superior Mesenteric Artery Syndrome: A Case of Duodenal Malrotation

Abstract

INTRODUCTION: Intestinal malrotation is a rare cause of mechanical bowel obstruction in adults. We describe a case of duodenal malrotation mimicking superior mesenteric artery syndrome. CASE DESCRIPTION/METHODS: A 22-year-old male with history of schizophrenia presented with abdominal pain and distension. He fasted for the past two months with 40 lbs weight loss, limiting himself to water in order “challenge himself.” The day prior to arrival, he ended his fast with a “large meal.” He immediately had abdominal pain and distension. Vital signs were normal. Labs were only remarkable for hypokalemia 3.4 mmol/g and trace levels of urinary ketones. CT revealed gastric distension filled with large air-fluid levels. An NG tube was placed for decompression with significant improvement. EGD revealed LA grade A esophagitis, mild diffuse gastric erythema, and a single 8 mm gastric ulcer with clean base. The endoscopist reported difficulty traversing from the second to third portion of duodenum and was concerned about extrinsic compression. MRE and upper GI series showed no obstruction. Both studies revealed that the duodenum did not cross midline and loops of jejunum in the right upper quadrant, indicative of malrotation. The patient improved gradually over several days and resumed a full diet. He was discharged to inpatient psychiatry with follow-up to assess for further surgical intervention. DISCUSSION: Bowel obstruction results from a mechanical or functional impedance of the intestines. Duodenal malrotation is a rare cause of mechanical obstruction. In adults, it occurs between 2%–5% of patients and most remain asymptomatic throughout life. Symptomatic patients typically present postprandially such as in ours, with also emesis, pain, failure to thrive, weight loss, and malabsorption. In our patient, the weight loss may likely have been due to poor intake due to the malrotation rather than the patient wishing to “challenge himself.” In a rare subset of malrotation patients, they present with a potentially life-threatening condition called acute midgut volvulus. Abdominal CT is the first line of screening and oral contrast studies are needed to confirm diagnosis. Treatment includes enteric tube for decompression, bowel rest, and possible surgical intervention. Patients presenting as adults with intestinal malrotation may be misdiagnosed, which can delay management. However, duodenal malrotation should be in the differential for patients presenting with obstruction without significant surgical history.Image 1.: The duodenum does not cross midline to the left with loops of jejunum seen in the right upper quadrant, indicative of malrotation.Image 2.: EGD image revealing narrowed second and third portion of the duodenum concerning for external compression.Image 3.: Descending duodenum is normal, however the 2nd portion of the duodenum does not cross the midline, but rather extends to the right. There is no distention of the duodenum to suggest SMA syndrome.