Small bowel bleeding remains a diagnostic challenge
While bleeding from the small intestine is relatively uncommon, it often presents a diagnostic challenge. Speaking at the Asian Pacific Digestive Week (APDW) 2017 held recently in Hong Kong, Dr Simon Lo from the Cedars Sinai Medical Center in Los Angeles, California, US, reviewed current guidelines and practices with a special focus on common pitfalls.
“Small bowel bleeding should be considered in patients with gastrointestinal [GI] bleeding with normal upper and lower endoscopic examinations. With evolving technologies in small bowel imaging with video capsule endoscopy [VCE], deep enteroscopy, double-balloon enteroscopy [DBE] and radiography, we now have many diagnostic tools available, and the guidelines have evolved accordingly,” said Lo. “Unfortunately, some of these technologies are available in tertiary-care centres only due to the associated cost, personnel training and long procedure time.”
The American College of Gastroenterology (ACG) recommends second-look examinations using upper endoscopy, push enteroscopy and/or colonoscopy before small bowel evaluation. VCE should be considered a first-line procedure for small bowel examination after other GI sources have been excluded by second-look endoscopy. Any method of deep enteroscopy can be used when there is a strong suspicion of small bowel lesion. Intraoperative enteroscopy is a highly sensitive but invasive diagnostic and effective therapeutic procedure; its use should be limited to scenarios where enteroscopy cannot be performed. [Am J Gastroenterol 2015;110:1265-1287]
“Intraoperative enteroscopy is the most reliable method to examine the entire small bowel, with a diagnostic sensitivity of around 80 percent. However, the therapeutic efficacy in preventing recurrent bleeding is only 41 percent,” said Lo. “It is also associated with significant complications, and prolonged recovery and hospitalization in about 30 percent of patients.”
“Negative imaging doesn’t mean a normal small bowel. You never know what you would find, as the source of the bleeding may not be what it appears to be. Even trivial-appearing polyps can still bleed,” he stressed. “In some cases, the diagnosis is not in question, but we still have a problem managing the bleeding as it may be deep within the lesion.”
Patients with Peutz-Jeghers syndrome who had undergone multiple operations pose a technical challenge. Surgical bypasses such as Roux-en-Y must also be assessed with deep enteroscopy.
“In patients with Crohn’s disease, strictures might preclude capsule studies and caution is recommended with enteroscopic evaluation and treatment,” suggested Lo.
Another dilemma is dealing with patients on anticoagulants who present with obscure GI bleeding. “When you see bleeding on heparin challenge, you better place a tattoo mark to identify the spot,” he advised. “Radionuclide bleeding scans can pick up very low-grade bleeding, but wrong localization has been reported in up to 25 percent of cases. Furthermore, they are time consuming, and we can’t really use them to direct treatment.”
“Many challenges remain with evaluations of obscure bleeding, such as cases of prior surgery or altered anatomy, false positive or negative results with VCE, patients on anticoagulation and the risks of intraoperative enteroscopy,” he concluded.