Gastroenterologic and Radiologic Approach to Obscure Gastrointestinal Bleeding: How, Why, and When?

Abstract

Gastrointestinal (GI) bleeding is a common clinical condition that is increasingly seen in an aging population and frequently requires hospitalization and intervention, with significant morbidity and mortality. Obscure GI bleeding (OGIB) is defined as loss of blood with no source identified after upper endoscopy and colonoscopy. Whether an obscure site of bleeding is clinically evident or silent, it constitutes a diagnostic and therapeutic challenge for the clinician. Gastroenterology and radiology provide the essential diagnostic tools used to evaluate suspected OGIB, each with its strengths and weaknesses. Small bowel series and conventional enteroclysis have a limited role in OGIB. Computed tomographic (CT) enterography and CT enteroclysis are noninvasive techniques with promising results in evaluation of small bowel disease and silent OGIB. CT angiography is a useful triaging tool for diagnosing or excluding active GI hemorrhage, localizing the site of bleeding, and guiding subsequent treatment. Tagged red blood cell scanning is the most sensitive technique for detection of active GI bleeding and allows imaging over a prolonged period, making it useful for detecting intermittent bleeding. Capsule endoscopy has emerged as an important tool for investigating OGIB, but it may soon have competition from double-balloon enteroscopy, a diagnostic technique that can also facilitate therapy.

Obscure gastrointestinal bleeding: diagnostic performance of 64-section multiphase CT enterography and CT angiography compared with capsule endoscopy

“…2,3 Based on the presence or absence of clinically evident bleeding, OGIB could be divided into occult (no visible blood) and overt (continued passage of visible blood, such as haematemesis, melaena or haematochezia) bleeding. 3,4 OGIB frequently occurs in the small bowel and is caused by small bowel diseases such as intestinal erosions, ulcers, vascular anomaly, gastrointestinal tumours and inflammatory bowel and parasitic diseases. 5,6 Multiple diagnostic techniques have been developed to elucidate the causes of OGIB.…”

“…Among them, two non-invasive technologies, capsule endoscopy (CE) and multislice CT (MSCT) markedly improved the ability to determine the causes of OGIB by allowing the visualization of the gastrointestinal tract. 2,3,6 CE is able to obtain direct visualization of mucosal surface of the entire small intestine. 4,7,8 However, capsule retention remains a major risk of CE diagnosis.…”

“…4,12 Yet, substantial patient radiation exposure is one of the major disadvantages of MSCT diagnosis. 3,13 Careful preparation is also needed before examination. 14 Considering that both CE and MSCT have advantages and disadvantages, a limited number of published data have compared the two diagnostic tools in patients with OGIB.…”

“…It has been reported that the main gastrointestinal lesions in young patients with OGIB are tumour, Meckel diverticulum and intestinal mucosal lesions such as Dieulafoy's lesion, Crohn's disease and Celiac disease. 3 Thus, the higher diagnostic yield in the younger than 40 years of age subgroup may owing to better tolerance to CE and high proportion of intestinal mucosal lesions in young patients with OGIB. Thus, we proposed that CE is the preferred method in the diagnosis of OGBI, especially for the patients with overt bleeding and for the cases aged younger than 40 years.…”

Radiographic techniques for the localization and treatment of gastrointestinal bleeding of obscure origin

“…Diagnostic signs of bleeding are intraluminal accumulation of radiotracer activity, increasing intensity of intraluminal activity over time, and movement of the radiotracer on successive images [29].…”