Meckel's Diverticulum Enterolith Presenting as Small Bowel Obstruction

Meckel's diverticulum (MD) is a common embryologic abnormality occurring in roughly 2% of the population. While most symptomatic patients will present in the first two years of life, a large subset of patients will be asymptomatic into adulthood. Of those patients, a minority will present with symptomatic disease with a variety of abdominal complaints.^1,2 We discuss the rare event of a Meckel's diverticulum enterolith causing a small bowel obstruction with associated intraluminal hemorrhage and the diagnostic imaging that can be used to better come to a definitive diagnosis.

A 46-year-old male with a history of chronic Hepatitis B and peptic ulcer disease presented with 12 hours of epigastric abdominal pain. His vital signs were a temperature of 98.7 degrees Fahrenheit, blood pressure of 103/68 mmHg, heart rate of 100 beats per minute, respiratory rate of 16 breaths per minute, and oxygen saturation of O2 99% on room air. Physical exam notable for diffuse abdominal tenderness with maximal pain in the epigastric area. Laboratory analysis demonstrated a white blood cell count of 12.4 (1000/mm³) but otherwise was within normal limits. Computed tomography (CT) of the abdomen and pelvis with intravenous contrast (100ml 250 Omnipaque) was obtained which revealed numerous dilated loops of small bowel with air-fluid levels and a discrete transition point in the ileum consistent with small bowel obstruction (Figure, transition point not shown). Just proximal to the transition point were two small radio-dense objects in the lumen surrounded by hyperdense layering material (Figure 2), which possibly represented ingested organic material such as a small animal bone.

Shortly after CT, the patient had a syncopal event, associated with hypotension (BP 91/55 mmHg) and hematochezia while trying to stand up to use the restroom. He was brought emergently to the operating room, where an 8 × 5cm Meckel's diverticulum was identified (Figure 3, yellow arrow) with acute diverticulitis and surrounding serosal adhesions. A small bowel resection including the diverticulum was performed and roughly one liter of intraluminal blood was removed along with the two calcified lesions which pathology later revealed to be fecaliths. Post-op course was largely unremarkable, notable only for delayed return of bowel function and he was discharged on post-op day 10 (figure 1).

MD is a congenital diverticulum on the ileum resulting from incomplete atrophy of the vitelline duct in the embryo. It was first described by the German anatomist Johann Friedrick Meckel in the early nineteenth century.¹ Complications from MD are rare occurrences in the adult population and can present with variable and vague abdominal complaints making it difficult to discern from more common abdominal pathologies. However, given the high prevalence of MD in the general population, it should be included in the differential diagnosis of patients presenting with non-specific abdominal pain without clear etiology. In addition, the various potential complications from MD should be considered including intussusception, hemorrhage, small bowel obstruction, and in rare cases, enteroliths.¹ The major risk factors for adult complications include male sex and age, with a 1% chance of complications at 40 years old, subsequently decreasing to zero by age 70 years old.³ There is currently no definitive imaging modality that is sensitive or specific enough to detect all cases of MD. Abdominal plain films may show radiopaque stones while ultrasound has the potential to show intussusception in children, but is of unclear utility in adults.^2,4 CT can provide the most useful information but it may be hard to differentiate MD from normal loops of small bowel.⁵ Intraluminal hemorrhage and small bowel obstruction are the most common complications of MD and can be seen on CT scan as fluid collecting in the small bowel or change in luminal diameter, respectively.⁶ Enteroliths are rare complications of MD. Ectopic gastric tissue seen in a majority of cases can cause extreme acidic environments in the intestinal tract causing precipitation of calcium or bile salts leading to stone formation. They can be seen as calcified hyperdense intraluminal material on CT but are rare and nonspecific for MD.⁷ Other studies have shown that they are more likely to be present in the right lower quadrant, have peripheral calcifications with radiolucent centers, and range from 1-5cm in diameter.^8,9 However, no one specific finding is sensitive or specific enough to definitely diagnose an MD enterolith. In our case, the idea of organic material ingestion (chicken bone) was entertained since the patient endorsed eating chicken wings the night prior, though had no recollection of accidentally swallowing a bone. Ultimately, final diagnosis and treatment depends upon surgical intervention. As seen in our patient, enteroliths causing obstruction can lead to large volume intraluminal bleeding that require critical care and rapid intervention. A high level of suspicion is necessary given the non-specific abdominal signs, though certain findings on imaging, as mentioned above, can provide insight that MD with associated enteroliths may be the diagnosis.