How to evaluate patients for suspected small-bowel bleeding

How to evaluate patients for suspected small-bowel bleeding

Identifying the source of a patient’s suspected small-bowel bleeding can be challenging for the practicing gastroenterologist. This article provides tips and tricks to help in the evaluation and management of the patient with suspected small-bowel bleeding.

1. Remember that small-bowel bleeding can present in a variety of ways. Small-bowel bleeding is suspected when a patient presents with gastrointestinal bleeding but has a negative upper endoscopy and colonoscopy, including second-look endoscopy where appropriate. It can present as overt or occult bleeding. Most patients present with chronic, intermittent small-bowel bleeding. Patients with occult bleeding present with unexplained iron-deficiency anemia with or without a positive fecal occult blood test and typically do not report visible blood. Patients with overt bleeding usually present with hematochezia or melena, depending on the location of the underlying source and rate of bleeding.
   
2. Always consider a repeat standard endoscopy before proceeding with capsule endoscopy. Evidence-based data on whether to repeat standard endoscopy or proceed with small-bowel endoscopy in suspected small-bowel bleeding are limited. Therefore, careful selection of patients for small-bowel evaluation is important to ensure a cost-effective approach towards management. Not insignificantly, up to 25% of lesions that are identified during the evaluation for suspected small-bowel bleeding are actually missed on initial upper endoscopy or colonoscopy. As such, based on the patient’s clinical presentation, one should consider repeating an upper endoscopy with or without a colonoscopy if bleeding limited the view in the previous study or a recent good quality examination has not been performed. When repeating an upper gastrointestinal evaluation, we often perform push enteroscopy in lieu of standard upper endoscopy to increase the depth of the exam. However, if high quality upper and lower endoscopic exams have recently been completed, a second-look endoscopy is likely not cost-effective and may be avoided.
   
3. It is important to understand how best to improve the yield of capsule endoscopy (CE). In general, the yield is greatest when CE is performed as soon as possible after the bleeding episode. In the hospitalized patient, the yield may be improved with early deployment of the capsule within 24–72 hours of admission. Other characteristics associated with an increased yield include history of an overt bleed, anticoagulant use, inpatient status, male sex, and older age, as well as liver and renal comorbidities. As such, one should attempt to complete the capsule study as early as possible and preferably on anticoagulation. Decreased capsule yields can also occur with poor bowel preparation or incomplete capsule studies where the capsule terminates recording prior to reaching the cecum. Incomplete capsule studies can occur in 20%–30% of patients. Risk factors for an incomplete study include hospitalization, small-bowel surgery, narcotic use, delayed gastric transit, and decreased physical activity. Patients should be encouraged to ambulate, especially hospitalized patients, as physical activity can improve small-bowel transit and lead to higher CE completion rates. Endoscopic placement of CE directly into the small bowel should be considered in patients with delayed gastric emptying or a prior incomplete capsule study. One should try to avoid gastric and small-bowel biopsies before CE to avoid confounding small-bowel findings due to blood and biopsy site ulcers.
4. Precautions should be taken to minimize the possibility of capsule retention. The most serious adverse event of CE is capsule retention which is defined as the presence of the capsule within the GI tract for at least 2 weeks or requiring an intervention to facilitate capsule passage or retrieval. Risk factors for retention include strictures, nonsteroidal anti-inflammatory drug (NSAID)-related diaphragms, tumors, diverticula, hernias, and history of gastrointestinal obstruction. From a clinical standpoint, it is important to note that most patients are asymptomatic and do not present with obstructive symptoms when the capsule endoscope is retained. In patients with risk factors for capsule retention, prior to proceeding with CE we perform a patency capsule exam to determine whether retention might occur. Cross-sectional imaging can also be helpful in evaluating small-bowel patency, but there have been cases where imaging did not successfully predict capsule retention. Patency capsules and cross-sectional imaging are likely complementary when predicting capsule retention.
   
5. It is important to understand the approach to deep enteroscopy in patients with suspected small-bowel bleeding. If a clinically significant small-bowel lesion is found on CE, deep enteroscopy is usually the next diagnostic and therapeutic tool to further evaluate and perform endoscopic treatment. The selection of which deep enteroscopy device is used, should be based on local experience and availability. Noninvasive CE is usually performed first to determine which patients might benefit from deep enteroscopy. An antegrade enteroscopy is pursued when lesions are found at a time index value less than or equal to 0.6 of the pylorus to cecal time, or less than 0.75 of ingestion to cecal time. A retrograde approach is used for lesions located more distally. An antegrade approach has been shown to have a greater diagnostic and therapeutic yield than a retrograde approach, likely due to a higher prevalence of vascular lesions in the proximal small bowel and deeper maximal depth of intubation with an antegrade approach. Similarly to CE, it is best to perform deep enteroscopy as close to the bleeding episode as feasible to improve diagnostic yield.
   
6. Remember to consider radiologic testing for patients with suspected small-bowel bleeding. One should proceed with small-bowel imaging if CE is negative or contraindicated, and in patients who present with brisk bleeding and hemodynamic instability. In addition, we consider cross-sectional imaging in those with suspected Crohn’s disease or a possible small-bowel mass lesion. Multiphase computed tomography (CT) scanning is the recommended first-line imaging technique if available. This technique utilizes intravenous contrast and scans during three phases: a bolus-triggered arterial phase, an enteric phase, and a delayed phase. While multiphase CT scanning should be considered as first-line imaging, magnetic resonance or CT enterography can be considered as an alternative. In an actively bleeding patient with relative contraindications to multiphase CT scans, such as chronic kidney disease, a radioisotope bleeding scan with technetium-99m (Tc-99m)-labeled red blood cell (RBC) scintigraphy can be considered.
   
7. Refractory bleeding can be challenging. Unfortunately, re-bleeding occurs in up to 45% of patients 2–3 years after endoscopic intervention. If patients continue to have bleeding after endoscopic and imaging evaluation, we pursue additional diagnostic options. In young patients, one should consider a Meckel’s scan to evaluate for ectopic gastric mucosa if this has not already been completed. In patients who are not transfusion-dependent and do not have other symptoms such as abdominal pain or weight loss that may require additional evaluation, it is often worthwhile to pursue a trial of oral or intravenous iron replacement. If the patient does not respond to conservative management, a repeat endoscopic and/or imaging evaluation may be necessary based on clinical suspicion. In addition, it is important to consider continuing the patient’s therapeutic anticoagulation or antiplatelet therapy prior to repeating endoscopic and radiologic testing in patients with refractory bleeding.
   
8. Medical management currently has a limited role in patients with small-bowel bleeding. We contemplate medical therapy only in a small group of refractory cases as there is a dearth of studies evaluating pharmacologic therapies. Consider medical therapy for patients who have multiple comorbidities and contraindications to endoscopy, particularly once a serious lesion has been excluded. Although it was once thought to be effective, recent studies have not shown any proven benefit of hormonal therapy in preventing bleeding secondary to vascular lesions. Somatostatin analogues and thalidomide may be useful for refractory small-bowel bleeding secondary to vascular lesions. The antiangiogenic, thalidomide, also appears to decrease re-bleeding rates and transfusion requirements and to improve anemia in patients with refractory gastrointestinal bleeding secondary to angioectasias. However, there are only limited data on the use of thalidomide in gastrointestinal vascular lesions. Further studies are required to evaluate the efficacy of somatostatin analogues and antiangiogenic agents in small-bowel bleeding.