Rare finding of primary aortoduodenal fistula on single-photon emission computed tomography/computed tomography of gastrointestinal bleeding: A case report

Abstract

Background: Primary aortoduodenal fistula is a rare cause of gastrointestinal (GI) bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage.

Case summary: A 67-year-old man was hospitalized for coffee ground vomiting, tarry stools, and colic abdominal pain. He was repeatedly admitted for active GI bleeding and hypovolemic shock. Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy, angiography, computed tomography angiography (CTA), capsule endoscopy, and ^99mTc-labeled red blood cell (RBC) scans. The patient received supportive treatment and was discharged without signs of rebleeding. Thereafter, he was re-admitted for bleeder identification. Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum. A ^99mTc-labeled RBC single-photon emission CT (SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level. According to his clinical symptoms (intermittent massive GI bleeding with hypovolemic shock, dizziness, dark red stool, and bloody vomitus) and the abdominal CTA and ^99mTc-labeled RBC SPECT/CT results, we suspected a small aneurysm and an aortoduodenal fistula. Subsequent duodenal excision and duodenojejunal anastomosis were performed. A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified. Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved.

Conclusion: Our findings suggest that ^99mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.

Keywords: 99mTc-labeled red blood cell scan; Case report; Computed tomography angiography; Gastrointestinal active bleeding; Primary aortoduodenal fistula; Single-photon emission computed tomography/computed tomography.

Figure 1

A 67-year-old man received multiple image examination, but each gastrointestinal active bleeding point was different. A: Esophagogastroduodenoscopy (EGD) showed three gastric ulcers, which were suspected Dieulafoy lesions; B: Small bowel endoscopy showed a shallow ulcer with pigmented spots in the small bowel; C: EGD showed duodenal diverticulum on the third portion; D: ^99mTc-red blood cell scan showed the radioactivity in the middle ascending colon to the hepatic flexure; E: Colonoscopy found two outpunching with dark brown content and mild oozing in the transverse colon.

Figure 2

We suggested the patient be admitted longer to find the bleeder. A: Computed tomography angiography arrow showed a small aortic aneurysm at the renal level, in contact with the fourth portion of the duodenum (orange arrow); B: ^99mTc-red blood cell scan showed an active bleeder at the duodenum level in the lateral view at 19 h, but other anterior views did not see any significant bleeding points (blue arrow).

Figure 3

Single-photon emission computed tomography/computed tomography localized a bleeding point at duodenum level. A: Single-photon emission computed tomography/computed tomography (SPECT/CT) transverse images (orange arrow); B: Top was CT three-dimensional (3D) images, middle was SPECT 3D images, and bottom was SPECT/CT 3D images (orange arrow).

Figure 4

Schematic diagram of percutaneous intravascular stenting of the abdominal aorta. Orange arrows showed the location of saccular aneurysm. A: Computed tomography angiography coronal image; B: Schematic diagram of the operative procedure.