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Updated: Jul 30, 2025

Blood Collection from the American Horseshoe Crab, Limulus Polyphemus
Published on: October 13, 2008
To Bleed or Not to Bleed
Peter A Iskander1, Syed Muhammad Hussain Zaidi1, Jiayi Zheng1
1Internal Medicine, The Wright Center for Graduate Medical Education, Scranton, USA.
The location of gastrointestinal (GI) bleeding can be characterized based on the characteristics of the bowel movements these patients present with. Bright red blood per rectum is usually associated with a lower bleed; if brisk and significant enough, however, upper bleeds can present similarly. Melenic or "tar-colored" bowel movements are more likely to occur from upper bleeds as the color is secondary to digestion of hemoglobin as it passes through the GI tract. At times, there can be a mix of the two which can make a clinical decision for intervention less obvious. To make matters more difficult, some of these patients can be on anticoagulation therapy for a myriad of reasons. Risks versus benefits at these times need to be weighed as holding this therapy may make the patients more prone to clotting while continuation would increase likelihood of bleeding. We present a case of a hypercoagulable patient who was started on rivaroxaban for history of pulmonary embolism; this led to the onset of an acute GI bleed from a duodenal diverticulum requiring endoscopic intervention. Although this can be a known effect of the therapy, the severity of bleed and changes in hemodynamics can warrant very different management strategies.
The location of gastrointestinal (GI) bleeding can be characterized based on the characteristics of the bowel movements these patients present with. Bright red blood per rectum is usually associated with a lower bleed; if brisk and significant enough, however, upper bleeds can present similarly. Melenic or "tar-colored" bowel movements are more likely to occur from upper bleeds as the color is secondary to digestion of hemoglobin as it passes through the GI tract. At times, there can be a mix of the two which can make a clinical decision for intervention less obvious. To make matters more difficult, some of these patients can be on anticoagulation therapy for a myriad of reasons. Risks versus benefits at these times need to be weighed as holding this therapy may make the patients more prone to clotting while continuation would increase likelihood of bleeding. We present a case of a hypercoagulable patient who was started on rivaroxaban for history of pulmonary embolism; this led to the onset of an acute GI bleed from a duodenal diverticulum requiring endoscopic intervention. Although this can be a known effect of the therapy, the severity of bleed and changes in hemodynamics can warrant very different management strategies.
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