Review Question - QID 106085

A patient with continued lower GI bleed not seen with colonoscopy can be localized with a highly sensitive tagged-RBC study such as technetium-99m scan.

The management should begin with stabilization of the patient, fluid resuscitation, and a type and cross. Once an upper GI cause is ruled-out via NGT on endoscopy, a lower source should be sought with colonoscopy. A technetium-99m-tagged red blood cell scan can be helpful. This involves removing a sample of the patient's blood, tagging with a radiolabeled tracer, and injecting it back into the circulation. A nuclear imaging study can then determine where the blood is entering the GI tract.

Manning-Dimmitt et al. outline the workup of a lower GI bleed. The diagnostic tool of choice for acute lower gastrointestinal bleeding is a colonoscopy, or arteriography if the bleeding is too brisk. When bleeding cannot be identified and controlled, intraoperative arteriography may localize the bleeding source allowing a segmental resection of the bowel. If no upper gastrointestinal or large bowel source of bleeding is identified, a technetium-99m-tagged red blood cell scan can be used.

Gutierrez et al. report that recent studies have shown scintigraphy to be superior to angiography as the primary diagnostic test in patients with lower gastrointestinal bleeding. The authors performed a retrospective analysis of 105 patients with the symptoms of lower GI hemorrhage and the role of a tagged RBC scintigraphy in their management. Surgical intervention was required in 25 patients, and the site of bleeding was correctly determined by scintigraphy in 22 of these patients (88%).

Illustration A shows an example of a tagged-RBC study. The arrows indicated the location of bleed.

Incorrect Answers:
Answer 1: NG tube aspiration with blood indicates an upper GI bleed and should be evaluated with upper GI endoscopy.
Answer 2: A bleeding source seen on colonoscopy should be managed with colonoscopic techniques to arrest bleeding.
Answer 3: A bleeding source not seen on colonoscopy when the patient stops bleeding should be followed conservatively and re-evaluated if the patient begins bleeding again.
Answer 5: A bleeding source not seen on colonoscopy when the arteriogram reveals bleeding source should be managed surgically by resection of the involved bowel segment.