American Board of Internal Medicine (ABIM) Certification Practice Exam

How can the cause of obscure gastrointestinal bleeding often be determined?

1. Through MRI of the abdomen

2. By repeating upper endoscopy or colonoscopy

3. With a CT scan of the abdomen

4. By patient's symptom self-report

The correct answer is: By repeating upper endoscopy or colonoscopy

The determination of the cause of obscure gastrointestinal (GI) bleeding often involves a methodical approach to locate the source of bleeding that standard endoscopic evaluations might have missed. Repeating upper endoscopy or colonoscopy is favored because these procedures allow direct visualization of the gastrointestinal tract, enabling the clinician to identify lesions, vascular abnormalities, or other pathological changes that could cause bleeding. In cases of obscure GI bleeding, first-line studies, such as an upper endoscopy or colonoscopy, may not reveal any abnormalities initially. Therefore, repeating these endoscopic evaluations with different techniques or focusing on different segments of the GI tract can sometimes uncover lesions that were previously overlooked. This is particularly true for conditions such as small bowel abnormalities, which can be challenging to visualize with standard techniques. Although imaging studies like CT scans have their place in the evaluation of GI bleeding, they are generally not as definitive as endoscopic procedures in directly visualizing and diagnosing the source of bleeding. A CT scan can be helpful in certain situations, such as identifying masses or vascular issues, but it does not provide the direct view of the mucosal surface that is often necessary for diagnosis. Additionally, while self-reporting symptoms can provide valuable context regarding the bleeding, it does not offer a tangible means for