Clinical History:

76-year-old male presenting with massive haematemesis and hypovolaemia.  Oesophago-gastroduodenoscopy showed a duodenal defect (D2/D3) with pulsatile bleeding that could not be controlled.  Patient was known to have locally advanced prostate cancer with low volume regional, iliac, and para-aortic lymph node involvement that was being managed with external beam radiotherapy.

 

Differential diagnosis:

Duodenal variceal bleeding in the context of portal hypertension

Duodenal Dieulafoy's lesion with arterial bleeding

Perforated duodenal ulcer with bleeding

Iliac artery-duodenal fistula

Angiodysplasia

 

Diagnosis:

Iliac artery-duodenal fistula

 

Imaging findings:

Figure 1:  Selected PET-CT images show the metastatic right sided para-aortic lymphadenopathy that was targeted by external beam irradiation.  This is involving the right ureter with resulting right sided hydroureteronephrosis, as seen in the coronal PET image.

 

Figure 2-3: Selected arterial phase axial CT images show large volume active extravasation of contrast in a distended duodenum.  Blood products are seen in the visible loops of small bowel.  A collection with bubbles of gas is seen between the duodenum and aorta.

 

Figure 4: Coronal multiplanar reformat with maximum intensity projection (thickness of 35 mm) shows a fistula between the medial aspect of the second/third portion of the duodenum and the superior portion of the right iliac artery just below the level of the aortic bifurcation.

 

Figure 5-6: Digital subtraction angiography confirms the findings seen in Figure 4.  This fistula was successfully closed using a 10 mm wide 5.8 cm long covered stent-graft, while preserving patency of the aorta and right common, internal, and external iliac arteries.

 

Discussion:

BACKGROUND

Aorta-enteric fistulas are a rare life-threatening cause for massive upper gastrointestinal bleeding.  More than 75% of aorto-enteric fistulas involve the duodenum, mostly at the third or fourth portion [1].  In our case, the fistula occurred between the medial aspect of the second/third portion of the duodenum and the superior portion of the right iliac artery.  Aorto-duodenal fistulation with upper gastrointestinal bleeding was first described in 1983 in the context of previous para-aortic/pelvic radiotherapy [2].  Other known causes include previous open surgery of abdominal aortic aneurysms (AAA) with or without the placement of an aortic stent-graft, AAA managed by endovascular repair (EVAR), untreated AAA, mycotic AAA, inflammatory conditions such as Behcet's disease, and primary or secondary malignancy extending to the aorta [3-5]. 

 

CLINICAL AND IMAGING PERSPECTIVE

Patients with aorto-enteric fistulas usually present with massive upper gastrointestinal bleeding that cannot be controlled endoscopically.  Prompt diagnosis is key in determining outcome – this is only possible if an urgent CT is done in patients presenting with massive upper gastrointestinal bleeding refractory to endoscopic intervention.  At our institution, abdominal/pelvic CT done in this clinical scenario includes a pre-contrast phase (5 mm slice thickness) followed with angiographic arterial and venous (1.25 mm slice thickness) phases timed through bolus tracking.  Positive oral contrast media should be avoided when imaging gastrointestinal bleeding.  Multiplanar reformats (MPR) with or without maximum intensity projection (MIP) images can also aid diagnosis.  The main diagnostic clue in this condition is a communication between the aorta/iliac arteries and neighbouring bowel, with active extravasation of contrast in the bowel lumen during the angiographic arterial phase and pooling of blood on the more delayed phases.  Fat stranding is seen between the affected loop of bowel and aorta, sometimes with an associated collection containing gas.  A large volume of mixed fresh and clotted blood is usually noted in the upstream/downstream bowel loops. .

 

OUTCOME

The traditional approach to aorto-enteric fistulas is urgent open surgery, with closure of the aortic defect [6].  If left untreated, this condition is almost always fatal [7].  Aorto-enteric fistulas can also be treated using a covered stent-graft, as illustrated in the present case.  Such an approach might be advantageous given that significantly less time is usually needed to puncture the femoral artery and deploy a covered stent graft under local anaesthesia (total procedure time in our case was less than 10 minutes), as compared with open closure of the aortic/iliac defect under general anaesthesia.

 

TAKE HOME MESSAGE

Aorto-duodenal fistula formation is a rare cause for upper gastrointestinal bleeding.  Prompt diagnosis using properly-protocolled CT is vital in ensuring early endovascular/surgical treatment.  This condition is lethal if left untreated.

 

References:

1. Drognitz O, Pfeiffenberger J, Schareck W, Adam U, Nizze H, Hopt UT (2002) [Primary aortoduodenal fistula as a late complication of para-aortic radiation therapy. A case report]. Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen 73 (6):633-637

2. Estrada FP, Tachovsky TJ, Orr RM, Jr., Boylan JJ, Kram BW (1983) Primary aortoduodenal fistula following radiotherapy. Surgery, gynecology & obstetrics 156 (5):646-650

3. Vu QD, Menias CO, Bhalla S, Peterson C, Wang LL, Balfe DM (2009) Aortoenteric fistulas: CT features and potential mimics. Radiographics : a review publication of the Radiological Society of North America, Inc 29 (1):197-209. doi:10.1148/rg.291075185

4. Ozguc H, Topal NB, Topal E (2008) Secondary aortoenteric fistula in a patient with Behcet disease: successful surgical treatment by direct suture and use of omental flap. Vascular 16 (5):300-302. doi:10.2310/6670.2008.00050

5. Vitturi BK, Frias A, Sementilli R, Racy MCJ, Caffaro RA, Pozzan G (2017) Mycotic aneurysm with aortoduodenal fistula. Autopsy & case reports 7 (2):27-34. doi:10.4322/acr.2017.015

6. Kim JY, Kim YW, Kim CJ, Lim HI, Kim DI, Huh S (2007) Successful surgical treatment of aortoenteric fistula. Journal of Korean medical science 22 (5):846-850. doi:10.3346/jkms.2007.22.5.846

7. Kalman DR, Barnard GF, Massimi GJ, Swanson RS (1995) Primary aortoduodenal fistula after radiotherapy. The American journal of gastroenterology 90 (7):1148-1150