Abstract
Background
Melena is a hallmark symptom of upper gastrointestinal bleeding and results from the digestion of blood lost proximal to the ligament of Treitz in the majority of cases. However, whether melena also predicts bleeding in the proximal small intestine (SI) in the setting of obscure gastrointestinal bleeding (OGIB) is unknown.
Aims
The objective of this study was to determine the predictive value of melena for determining the location of SI bleeding in OGIB.
Methods
A retrospective cohort study was conducted of all patients who underwent capsule endoscopy (CE) for OGIB at London Health Sciences Centre between 2009 and March 2016. The presenting symptoms were recorded and categorized as melena or non-melena (ie. hematochezia and occult OGIB with iron deficiency anemia (IDA)). The primary outcome was diagnosis of a bleeding site between 0 - 50% SI transit time. Baseline demographics, comorbidities, medication usage, hemoglobin, and blood transfusion requirements were noted. The association between melena and proximal SI bleeding was determined using chi-square.
Results
312 patients underwent CE for OGIB during the study period. Mean (SD) age was 63.9 years (15.4), and 55% were female. 36% of patients had melena, 14% had hematochezia, and 48% had only IDA. Blood transfusion was required within the past 12 months in 70% of patients and 14% of cases were performed as inpatients. The mean (SD) follow-up time was 16 months (24.1). The overall diagnostic rate was 45%, with angioectasias being the most common etiology (27%). 46% of patients with melena had a bleeding site within the proximal half of the SI compared to 31.3% who did not have melena (RR 1.47, p=0.01). The mean (SD) SI transit time for bleeding site was 21.2% (25.8) for those with melena and 34.7% (33.4) for those without (p=0.008).
Conclusions
The probability of locating a bleeding site within the proximal half of the SI is 47% greater among OGIB patients with melena than those without. As such, antegrade double balloon enteroscopy without preceding CE may be warranted in this population.
Melena vs Hematochezia+IDA+Melena&Hematochezia
| Melena | Non-Melena | p-value | |
|---|---|---|---|
| Bleeding site by % of SI transit time-mean (SD)* | 21.2% | 34.7% | 0.008 |
| Bleeding site in proximal 1/2 of SI | 46% | 31.3% | 0.014 |
| Bleeding site in proximal 1/3 of SI | 40% | 29.6% | 0.08 |
*Among those where a SI bleeding site is found. RR for prox 1/2 SI=1.47 (1.09–2.0, p=0.014). RR for prox 1/3 SI=1.35 (0.97–1.88, p=0.08)
Funding Agencies
Schulich Research Opportunities Program