Unfortunately, the approach to severe hematochezia is often less clear. Below is a description of how these cases often unfold. The diagnostic evaluation is frequently inconclusive. Fortunately, most cases of lower GI bleeding are due to diverticulosis or angiodysplasia and these generally stop without specific intervention.
Building Blocks: Performance of various tests
Diagnostic Nasogastric Lavage
Tagged RBC scan
CT Angiography (CTA)
(1) Detection and characterization of obscure bleeding sites
(2) Diagnosis of other abdominal pathologies that present with hematochezia
(3) Speed and availability
“CTA should be the standard of care for assessment of patients presenting with acute lower GI bleed”
– Chan et al. 2014, John Radcliffe Hospital, Oxford UK.
(4) Ability to target invasive angiography or surgery
(5) Immediate prognostication and triage
Drawbacks: Safety concerns
Above is flexible approach to severe hematochezia incorporating CT angiography and clinical judgment. This is not truly “new,” as various CTA-based approaches have been advocated for several years and are already utilized in many centers (e.g. Copland 2010). However, knowledge translation has often been sluggish.
- Abdominal CT angiography is a fast test with high performance to reveal bleeding anywhere in the GI tract. CTA has already replaced tagged RBC scanning in many centers.
- An approach incorporating physician judgment, NG lavage, and CTA may allow for thorough evaluation of hematochezia without subjecting every patient to an upper endoscopy (EGD).
- In situations where endoscopy is not immediately available, CTA may allow for rapid and accurate evaluation of hematochezia. This may help identify which patients require immediate intervention and which patients can be safely observed.
- Copland A et al. Integrating urgent multidetector CT scanning in the diagnostic algorithm of active lower GI bleeding. Gastrointestinal Endoscopy, 2010; 72(2) 402-405.
- Artigas JM et al. Multidetector CT angiography for acute gastrointestinal bleeding: Technique and findings. Radiographics 2013; 33: 1453-1470.