Methylene Blue injection via superior mesenteric artery microcatheter for focused enterectomy in the treatment of a bleeding small intestinal arteriovenous malformation

INTRODUCTION: Obscure gastrointestinal bleeding from the small intestine may present the Acute Care Surgeon with a formidable diagnostic and therapeutic challenge. Despite the current array of diagnostic studies, localization of the causative pathology may be elusive, especially when the bleeding is intermittent. When a small intestinal arteriovenous malformation is the responsible lesion, a technique combining super-selective angiography with intra-operative methylene blue injection and focused enterectomy has been described in a number of case series. The current case report utilizes this same approach with emphasis on computed tomography angiography representing a key first step in the diagnostic algorithm. CASE REPORT: In this case report, we describe the diagnosis and treatment of obscure gastrointestinal bleeding emanating from an arteriovenous malformation in the small intestine of a 52 year old male. After an extensive work-up including upper and lower endoscopy, double balloon enteroscopy and capsule endoscopy, he was referred for computed tomography angiography. Though he was not actively bleeding, a jejunal arteriovenous malformation was localized on imaging. This prompted directed transfemoral angiography, placement of a super-selective microcatheter in the 4th jejunal arterial branch, intra-operative methylene blue injection and focused enterectomy with pathological confirmation. The patient was found to be free of gastrointestinal bleeding on 6 month follow-up. CONCLUSIONS: A step-wise, rational diagnostic approach should be utilized in the evaluation of obscure gastrointestinal bleeding. In the non-actively bleeding patient, computed tomography angiogram may facilitate the diagnosis of a small intestinal arteriovenous malformation. Methylene blue injection via a super-selective angiographic microcatheter may then allow for focused enterectomy.