Obscure-overt gastrointestinal bleeding: a review.

Obscure gastrointestinal (GI) bleeding (OGIB) is defined as small bowel bleeding of unknown etiology after negative endoscopic evaluation including esophagogastroduodenoscopy and colonoscopy with endoscopic evaluation of the terminal ileum. The presentation of OGIB may be either overt or occult. The former refers to persistent or recurrent visible GI bleeding (eg, melena and / or hematochezia, and rarely hematemesis), while the latter indicates the presence of persistently positive results of fecal oc-cult blood testing, iron deficiency anemia, or both, without evidence of visible GI bleeding. This review focuses exclusively on obscure‑overt GI bleeding and presents entities that should be considered as part of the differential diagnosis in patients with this type of bleeding, as well as details the role of endoscopic and radiographic techniques in the evaluation and treatment.