What radiologic tests are available for patients with GIBOO and what is their yield?
• Small bowel series: Yield is only approximately 10%. Disadvantages: misses angiodysplasia, and contrast in the gut obscures and precludes angiography.
• Enteroclysis: Yield is approximately 15%. Disadvantages: misses angiodysplasia, and contrast in the gut obscures and precludes angiography.
• Computed tomography enterography: Method is good for Crohn’s disease and small bowel tumors. Disadvantages: misses angiodysplasia, and contrast in the gut obscures and precludes angiography.
• Nuclear medicine bleeding scan: 99 m technetium is attached to autologous erythrocytes ex-vivo and then reintroduced intravenously. Extravasated blood in the bowel lumen confirms active bleeding. GI bleeding low as 0.1 to 0.5 mL per minute can be detected, but localization is generalized to abdominal regions.
• Mesenteric angiography: Yield is approximately 20%. A bleeding scan is often performed first to confirm that bleeding is active, followed via mesenteric angiography. Angiography may be therapeutic. Actively bleeding lesions can be arrested by embolization with gelfoam or metal coils delivered by the angiographic catheter. The major risk of therapeutic embolization is mesenteric ischemia, which has decreased to 1% or less with super-selective cannulation.
When a patient is referred to a tertiary center for GIBOO, is it worthwhile for the specialized gastroenterologist at this center to repeat another EGD or colonoscopy before performing specialized small bowel examinations?
Patients referred to a tertiary center for GIBOO usually undergo repeat EGD and colonoscopy. The yield on repeat EGD is approximately 10%. Commonly identified lesions include Cameron ulcers or erosions within a hiatal hernia, peptic ulcers, vascular angiodyplasia, gastric antral vascular ectasia, and Dieulafoy lesions. Esophageal varices that were thought to be incidental findings on the first EGD may be recognized as the bleeding source on repeat EGD by finding stigmata of recent hemorrhage on the varices, such as wale bites or red streaks. When a cause of iron-deficiency anemia is not identified, normal-appearing duodenal mucosa should be biopsied to exclude possible celiac disease.
Repeat colonoscopy is especially important when the initial procedure was hampered by incomplete or poor bowel preparation. Commonly identified lesions at repeat colonoscopy include colon cancer, angiodysplasia, diverticular bleeding, and Crohn’s colitis.