Obscure GI bleeding has been defined as bleeding which persists or recurs after upper and lower endoscopy and radiographic evaluation of the small bowel. Comprising up to 5% of cases of GI bleeding with 75% of them localizing to the small intestine
, these patients may require multiple blood transfusions and be subject to a battery of repeat diagnostic studies before definitive diagnosis is accomplished. The most likely etiologies are broken down by age group. In patients younger than 40, the most likely lesions include Meckel’s diverticulum, inflammatory bowel disease, or a small bowel tumor such as a gastrointestinal stromal tumor (GIST), lymphoma, carcinoid, polyp or adenocarcinoma. In contrary, patients older than 40 are most likely to have bleeding from vascular anomalies, erosions or NSAID-related ulcerations. Overall, vascular lesions comprise 40% of all causes
Two years after Fogler and Golembe’s description of open cannulation of the superior mesenteric artery, Athanasoulis and colleagues in 1980 described the placement of super-selective angiographic catheters and intraoperative methylene blue injection to localize and treat two patients with AVMs and one with ulcerations in the small intestine
. Refinements on the technique have been described in subsequent reports which have paralleled advancement in angiographic methods, including provocative angiography with fibrinolytic agents
From these reports, several guiding principles can be elucidated. When the AVM is localized on angiography, the most distal arterial tributary should be cannulated by a microcatheter and safely secured for transport. This can be done in the angiography suite or a hybrid operating theater. Following this the small bowel must be exposed either via a limited midline laparotomy or laparoscopy before injection of methylene blue. The limited segment of small bowel, usually 10cm or less is readily identified and resected with pathological confirmation. Clinical success is confirmed by long-term follow up.
After a careful review of the literature, this report represents the first case in the utilization of CTA in the diagnosis of a non-actively bleeding small bowel AVM which then enabled focused angiography and subsequent limited enterectomy. The CTA demonstrated the abnormality in the left-sided, proximal jejunum which corresponded to the 4th jejunal branch by transfemoral angiography. Not only did this spare the patient additional contrast load, it may have not been localized, or required provocative angiography, with its inherent risks, if not for the pathological finding on CTA. As the quality of the CTA has improved with new generation scanner technology, this diagnostic study should be considered in the work-up of the non-actively, obscure GI bleeding patients, with a focus on small bowel lesions and AVMs. Further study is warranted to truly gauge its sensitivity and specificity in this patient population.