Case Presentation: A 21 year old male with no past medical history presented with black and bloody stools for one day.  He also reported accompanying fatigue, lightheadedness, nausea without vomiting as well as abdominal bloating.  He denied any history of gastrointestinal bleed as well as prior esophagogastroduodenoscopies (EGD) or colonoscopies.  His exam was remarkable for tachycardia and diffuse abdominal tenderness.  An EGD did not identify a source of bleeding and a colonoscopy showed dark blood throughout the colon with red blood at the terminal ileum, but no culprit lesion.  He underwent a CTA, which did not identify any active bleeding.  With only resuscitative interventions, the patient temporarily stopped bleeding and a tagged RBC scan was cancelled.  A Meckel’s nuclear scan was negative.  However, the patient again began to bleed and was taken for a laparoscopy with EGD, which revealed a Meckel’s diverticulum in the ileum that was resected without complication.

Discussion: Meckel’s diverticulum (MD) is the most common congenital malformation of the gastrointestinal tract, present in 2-4% of the population and due to persistence of the vitello-intestinal duct. While the majority of instances occur in the pediatric population, two large systematic reviews of 1476 and 776 patients with MD, found that among those who are symptomatic, 75% are older than 11 years old and 30% are older than 20 years old. The most common complications are bleeding (29-38%) and obstruction (34-43%). Bleeding occurs as a result of ectopic gastric mucosa leading to acid induced ulceration of the adjacent ileum (Kusumoto et al, Park et al). Diagnosis is most often made using the technetium-99m pertechnetate scan whose tracer has a propensity to concentrate in gastric mucosa. However, it’s sensitivity is 62.5% and specificity 9% (Sagar et al). The high incidence of false negatives may be attributed to rapid dilution of radiactivity secondary to brisk bleeding, impaired vascular supply, or an insufficient amount of gastric mucosa. One method shown to improve diagnostic yield is the administration of an H2 antagonist prior to imaging, which increases pertechnetate retention within the gastric mucosa. No studies have been evaluated in the adult population; however in a pediatric study sensitivity was increased from 37% to 87% (Rerksuppaphol et al). Additionally, if clinical suspicion remains high despite an unrevealing scan, endoscopy with laparoscopy is preferred for diagnosis, as management would be surgical removal of the diverticulum.

References
Kusumoto H, Yoshida M, Takahashi I, et al. Complications and diagnosis of Meckel’s diverticulum in 776 patients. Am J Surg 1992; 164:382.

Park JJ, Wolff BG, Tollefson MK, et al. Meckel diverticulum: the Mayo Clinic experience with
1476 patients (1950-2002). Ann Surg 2005; 241:529.

Rerksuppaphol S, Hutson JM, Oliver MR. Ranitidine-enhanced 99mtechnetium pertechnetate
imaging in children improves the sensitivity of identifying heterotopic gastric mucosa in
Meckel’s diverticulum. Pediatr Surg Int 2004; 20:323.

Sagar J, Kumar V, Shah DK. Meckel’s diverticulum: a systematic review. J R Soc Med 2006;
99:501.

Conclusions: Meckel’s diverticulum should be considered in all young adults without obvious etiology of their gastrointestinal bleed. If clinical suspicion is high, an unrevealing scan does not adequately rule out the diagnosis and further endoscopic evaluation with laparoscopy may be necessary.