S4680 Unmasking the Hidden Bleed: A Rare Case of Lower GI Bleeding Originating from a Colonic Segment Within a Ventral Hernia Sac

Introduction: Lower gastrointestinal bleeding (LGIB) in elderly patients is often challenging to diagnose, especially when confounded by altered anatomy or cognitive impairment. Bleeding from bowel segments within hernia sacs is rare and may evade detection with standard imaging and endoscopy. Case Description/Methods: An 89-year-old woman with paroxysmal atrial fibrillation on rivaroxaban, stage IIIB chronic kidney disease, vascular dementia, and a large ventral hernia presented with symptomatic anemia (hemoglobin 5.9 g/dL) and no overt signs of gastrointestinal bleeding. Initial computed tomography angiography (CTA) showed no active bleeding. Over several days, she received multiple blood transfusions for persistent hemoglobin decline. Superior mesenteric angiography, 2 sessions of deep enteroscopy, and a colonoscopy were all nondiagnostic. Colonoscopy was complicated by colonic redundancy due to hernia, poor visualization from inadequate bowel preparation (BBPS = 3), and her inability to cooperate due to delirium. The procedure was aborted early, though diffuse hematin was observed throughout the colon. A repeat CTA performed several days later revealed active contrast extravasation within a portion of the transverse colon herniated into the ventral hernia sac. Interventional radiology successfully embolized the culprit segment, resulting in hemodynamic stabilization and cessation of transfusion requirements. Discussion: This case underscores the complexity of diagnosing LGIB in elderly patients with cognitive impairment and anatomical distortion. CTA, though highly sensitive and specific in active LGIB, may miss intermittent or anatomically sequestered bleeds. Colonoscopy remains a vital tool but is limited by poor prep and challenging anatomy. Bleeding from bowel entrapped in a hernia sac is extremely rare, with most literature focusing on strangulation or ischemia rather than hemorrhage. In our case, repeat imaging and a high index of suspicion were key to diagnosis. Early involvement of interventional radiology was critical in achieving hemostasis. Clinicians should consider hernia-related bowel bleeding when standard evaluations are inconclusive and initial imaging is negative.