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.