Obscure Gastrointestinal Bleeding from a Meckel's Diverticulum in a Young Adult: A Challenging Diagnosis

Introduction: Meckel’s Diverticulum (MD) is the most prevalent congenital abnormality of the gastrointestinal tract.Diagnosis in adults can be challenging and potentially life-threatening if delays occur due to its clinical presentation that can mimic many other causes of gastrointestinal pathology so an early diagnostic suspicion might improve clinical outcomes. Case Description/Methods: A 25-year-old male presents with a 6-day history of multiple episodes of hematochezia. He denied hematemesis, NSAID use or other symptoms. His initial hemoglobin (Hb) decreased from 12 mg/dl to 6.5 mg/dl requiring an urgent EGD, however no active source of bleeding was found. Hematochezia continued the next day, he was tachycardic but normotensive on exam and his follow up Hb was 5.4 mg/dl. A repeat EGD showed erosion in the prepyloric area and a colonoscopy revealed blood in the entire colon up to the ileum. An abdominal CT angiography revealed a small amount of intraluminal hyperdense material in the descending colon suspicious for a possible site of active bleeding. A repeat colonoscopy found old blood in the colon but did not reveal the source of bleeding. During his hospital course, profuse bleeding continued and the patient required massive transfusion of 14 units of blood. On the fourth day of admission, a Meckel scan revealed focal uptake overlying a small bowel loop in the right hemipelvis likely representing ectopic gastric mucosa highly suspicious for MD given its location. An urgent laparoscopic resection of MD with primary anastomosis was performed. After surgery, the Hb remained stable at 10 mg/dl. Recovery was uneventful and follow-up 2 weeks after surgery was uncomplicated. Discussion: MD in adults can have diverse presentations including painless bleeding, intestinal obstruction or abdominal pain that might be confused with appendicitis or colonic diverticulitis. Diagnosis is challenging and many times initial imaging techniques to exclude other GI pathologies might miss this diagnosis. Obscure GI bleeding cases are often attributed to small bowel lesions or missed lesions in endoscopy due to brisk bleeding. In these cases, MD must be high in the differential for the work up to include a Meckel’s scan. Though rarely symptomatic in adults, given its high prevalence as a congenital abnormality of the GI tract it must always be considered amongst the differential diagnosis. Meckel’s diverticulectomy is the treatment of choice. High suspicion is necessary to avoid complicationsof delayed surgical intervention.Figure 1.: Nuclear medicine study showing focal area of increased uptake in the right hemipelvis above the bladder appearing to intensify at the same rate as the uptake in the gastric mucosa, likely representing ectopic gastric mucosa such as that seen in a Meckel's Diverticulum.