Meckel’s Diverticulum as a Cause of Bowel Obstruction Dana Goverman MS4 Washington University in St. Louis

Case of TW 14 yo M transferred from an outside ED with increasing fatigue, colicky abdominal pain and non-bilious emesis for a 1 day Sudden onset, worsening, migrated to the RLQ History of open appendectomy for perforated appendicitis 1 year ago Outside labs showed a chronic microcytic anemia

Exam and Labs T 37.2, HR 66, RR 14, BP 119/63 Tender over the RLQ persistently with mild percussion tenderness, no involuntary guarding, no rebound. Guaic positive stool at outside ED UA within normal limits 6.5 136 104 12 7.8 266 126 24.4 3.6 23 0.7 MCV 58.8

CT Scan Although intestinal obstruction is the second most common complication of Meckel diverticulum, the diagnosis is rarely made preoperatively. The diagnosis can be made with certainty only if the diverticulum is visualized at the site of obstruction. Computed tomography (CT) is an invaluable imaging modality for the evaluation of patients with intestinal obstruction. However, it is difficult to use CT to accurately identify a Meckel diverticulum as the cause of intestinal obstruction. Moderate to severe dilation of distal jejunum and proximal ileum Most pronounced in the pelvis Fecalization of the intraluminal contents suggests a chronic process

Differential Diagnosis Adhesive small bowel obstruction Crohn’s disease Partial segmental volvulus Meckel’s diverticulitis

Operative Findings Diagnostic laparoscopy - minimal adhesions One adhesion from the cecum to the underside of the incision that was non-obstructing Large Meckel’s diverticulum completely filling the deep pelvis High-grade obstructing adhesions were taken down laparascopically with an open resection of the Meckel’s diverticulum

Operative Findings Will put photo here. The photo made the file too large to send

Embryology Omphalomesenteric duct connects the fetal gut to the yolk sac Normally involutes between weeks 5-6 of development Failure of regression on the antimesenteric border of the ileum leaves a persistent diverticulum It is the most common congenital anomaly of the gastrointestinal tract and is a remnant of the vitelline (omphalomesenteric) duct. In utero, the vitelline duct connects the fetal gut to the yolk sac. The duct usually involutes during the fifth to sixth weeks of gestation. When the portion of the vitelline duct that is on the antimesenteric border of the ileum fails to regress, it forms a true diverticulum. A number of anatomic variations. Anatomically, 2 feet (from the ileocecal valve). 2 inches (in length), 2 types of common ectopic tissue (gastric and pancreatic). Schropp and Garey. Meckel’s Diverticulum [41-2]. In Holcomb and Murphy Ashcraft’s Pediatric Surgery .

Epidemiology 2% incidence 4-6% become symptomatic 2:1 male to female ratio Average age of presentation is 2-years-old Park, JJ. et al. (2005)

Meckel’s Presentations Melena or bleeding per rectum (56%) Diverticulitis or peritonitis (16%) Obstruction (14%) Patent omphalomesenteric duct (14%) Incidental finding at laparotomy There are many mechanisms for small intestinal obstruction from a Meckel diverticulum. These mechanisms include intussusception; volvulus or internal hernia from persistent attachment of the diverticulum to the umbilicus by the obliterated omphalomesenteric duct, mesodiverticular band, or adhesion; luminal obstruction from an inverted diverticulum, diverticulitis, or foreign body impacted in the diverticulum; inclusion of the diverticulum into a hernia; neoplastic obstruction; or rarely, the inclusion of a Meckel diverticulum in a true knot that forms between the ileum and sigmoid. Menezes M, Tareen F, Saeed A et al. (2006)

Variation Among Presentations Mean age of patients in the intestinal obstruction group was significantly younger than in the intestinal bleeding group (3.7 vs. 6.6). This goes against older data suggesting that an obstructive presentation is most common in adults rather than the pediatric population. In the diverticulitis and obstruction groups, the most common manifestations were emesis and abdominal pain 8 of the 12 patients with obstruction found to have intussusception as the cause, and half of these patients were over age 3 Distance to the ileocecal valve was the same between groups Heterotopic mucosa is more frequently found in the bleeding group than in the obstructive Tseng Y and Yang Y. (2009)

Appendicitis Secondary to Meckel’s 5 mo M infant admitted with fever for 7 days, vomiting, loose stools and abdominal fullness for 2 days Ex-lap revealed a large pseudocyst in the peritoneal cavity containing frank pus, ruptured Meckel diverticulum and an inflamed appendix in the wall of the abscess Atypical pathology with outer layers of inflammation but intact epithelium Possibilities for TW’s illness the year prior are multiple. It is possible that he had an independent episode of appendicitis, unrelated to his Meckel’s. Another possibility is that he never had appendicitis and that his pain was due to a previous episode of Meckel’s diverticulitis. Finally, there are two reported cases of Meckel’s diverticulitis leading to intra-abdominal inflammation and secondary appendicitis. Case 1: As shown on slide Case 2: 37-year-old man with symptoms of acute appendicitis. A severely inflamed appendix was removed. Histology, however, showed an atypical picture of inflammation: the outer layers of the appendix were severely inflamed but the epithelium was intact. Re-laparotomy revealed an abscess around a perforated Meckel's diverticulum, with no evidence of complications at the site of appendicectomy. It appeared that the appendix had become inflamed directly from the primarily inflamed Meckel's diverticulum. The case shows that a careful exploration of the neighbouring organs as well as the dissection of the specimen by the surgeon himself is indicated during laparotomy despite detection of appendicitis. To distinguish the situation described here from classical appendicitis we suggest the term secondary appendicitis to define the direct invasion of inflammation to the appendix from an adjacent organ.

Conclusions Obstruction is a well-described presentation of Meckel’s diverticular disease Obstructive presentation may be more common at young ages than was previously thought Presenting symptoms are emesis and abd pain There are reported cases of Meckel’s disease leading to secondary appendicitis, reinforcing the importance of careful abdominal exploration during appendectomy.

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