A Rare Cause of Duodenal Obstruction

Abstract

Purpose: Aortoduodenal syndrome is described as compression of the duodenum by a AAA presenting as gastric outlet obstruction. Described by Osler in 1905, it is modestly reported in the literature. Symptoms include vomiting, abdominal pain, distention, weight loss, electrolyte imbalance, and a pulsatile abdominal mass. It is associated with aspiration pneumonia, renal failure, and aortic rupture. Diagnosis is made by CT or UGIS. EGD is useful to rule out other causes of obstruction, to visualize compression by a pulsatile mass, to obtain tissue, and for possible intervention. Treatment includes fluid and electrolyte replacement, NGT decompression, nutritional support, and surgical intervention. We describe a case of an 80 yo man who presented with intractable vomiting. He complained of epigastric pain, weight loss, and a nonproductive cough. On admission, he had a leukocytosis and was started on antibiotics for pneumonia. CT revealed gastric and duodenal distention with a transition zone in the distal duodenum along a 4.6 cm aortic aneurysm. NGT drained 3 liters of dark fluid. EGD was recommended, but the family declined. He was started on TPN and underwent a Roux-en-Y gastric bypass. No mass or anatomic abnormality was identified during the surgery, which confirmed the diagnosis. The patient was able to tolerate PO intake and was discharged. Aortoduodenal syndrome remains a rare entity of unknown etiology. Similar to cases described in the literature, the patient's AAA was described as an infrarenal, non-inflammatory aneurysm. The aneursymal sac measured 4.6 cm, while most previously described sacs were typically 8-10 cm. The patient also suffered from the classically associated comorbidities of aortoduodenal syndrome. His case was unique because it was associated with significant weight loss likely secondary to compression of the duodenum by an existing AAA, rather than the more commonly reported SMA syndrome. We report this case to review the presentation, diagnosis, and treatment of aortoduodenal syndrome. Aortoduodenal syndrome should be included in the differential diagnosis of gastric outlet obstruction, particularly in patients at risk for AAA.Figure