Obscure Gastrointestinal Bleeding – A Multimodal Imaging Approach

Gastrointestinal (GI) bleeding represents one of the most frequently encountered clinical case scenarios in the emergency department. In the United States, the annual rate of hospitalization for any type of GI hemorrhage accounts for 300/100,000 population, with more than 1,000,000 hospitalizations each year and an approximately mortality rate of 5%. Upper GI bleeding (UGIB) is more common than lower GI bleeding (LGIB), yet there are many sites and multiple lesions from which bleeding could occur and the source could remain unidentified after upper endoscopy or colonoscopy evaluation. The uncertain etiology of GI hemorrhage is traditionally defined as obscure GI bleeding (OGIB) and constitutes a diagnostic challenge, so accurate investigations are crucial. Even if the mainstay of initial evaluation consists of upper endoscopy, colonoscopy or contrast X-ray studies, current guidelines suggest that video capsule endoscopy, push enteroscopy, angiography and radionuclide imaging are best suited, allowing an appropriate examination of the entire small bowel, which represents the most common source of OGIB. Hence, the aim of this review is to provide a multimodal investigation approach a