Pediatric Meckel Diverticulum

Updated: Oct 20, 2017
  • Author: Simon S Rabinowitz, MD, PhD, FAAP; Chief Editor: Carmen Cuffari, MD  more...
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Overview

Background

Meckel diverticulum (also referred to as Meckel's diverticulum) is the most common congenital abnormality of the small intestine; it is caused by an incomplete obliteration of the vitelline duct (ie, omphalomesenteric duct). Although originally described by Fabricius Hildanus in 1598, it is named after Johann Friedrich Meckel, who established its embryonic origin in 1809. [1]

Despite the availability of modern imaging techniques, diagnosis is challenging. Although Meckel diverticulum is usually asymptomatic, two types of complications can require clinical attention. One type involves ectopic mucosal tissue and most often leads to GI bleeding in younger children. In the second type, an obstruction, inflammation, or, rarely, perforation of the bowel is present.

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Pathophysiology

The yolk sac is the first element to be formed within the gestational sac. It is involved in maternal-fetal transfer of nutrients in early gestation during the critical period of organogenesis. Early in embryonic life, the fetal midgut receives its nutrition from the yolk sac via the omphalomesenteric/vitelline duct. The duct then undergoes progressive narrowing and usually disappears by 7 weeks' gestation. When the duct fails to fully obliterate, different types of vitelline duct anomalies appear. Examples of such anomalies include (1) a persistent vitelline duct (appearing as a draining fistula at the umbilicus); (2) a fibrous band that connects the ileum to the inner surface of the umbilicus; (3) a patent vitelline sinus beneath the umbilicus; (4) an obliterated bowel portion; (5) a vitelline duct cyst; and, most commonly (97%) Meckel diverticulum, which is a blind-ending true diverticulum that contains all of the layers normally found in the ileum. [2] The tip of the diverticulum is free in 75% of cases and is attached to the anterior abdominal wall or another structure in the remainder of cases.

Enterocystomas, umbilical sinuses, and omphaloileal fistulas are among the other congenital anomalies associated with Meckel diverticulum.

The diverticulum is usually supplied by the omphalomesenteric artery (a remnant of the vitelline artery), which arises from the ileal branch of the superior mesenteric artery. Usually, the artery terminates in the diverticulum; however, it has been reported to continue up to the abdominal wall in some cases. Rarely, these blood vessels persist in the form of fibrous remnants that run between the Meckel diverticulum and the abdominal wall or small bowel mesentery.

A rare case of Meckel diverticulum reported was associated with other umbilical anomalies; a 4-year-old boy presented with abdominal pain, vomiting, and constipation. [3]  Upon surgical exploration, he was found to have a band arising from a Meckel diverticulum, causing obstruction of the terminal ileum. An urachal cyst at the umbilicus was attached to the Meckel diverticulum at one end and to the urinary bladder on the other end through a patent urachus.

Although Meckel diverticulum almost always occurs on the antimesenteric border of the ileum, case reports have described a mesenteric location. As per the rule of 2s, it is usually 2 feet (40-60 cm) proximal to the ileocecal valve, 2 cm wide (and is 3 cm long), found in 2% of the population, [4] often presents before age 2 years, is twice as likely to be symptomatic in boys, and contains ectopic mucosa about half the time. Meckel diverticulum is typically lined by ileal mucosa, but other tissue types are also found with varying frequency.

The heterotopic mucosa is most commonly gastric. This is important because peptic ulceration of this or adjacent mucosa can lead to painless bleeding, perforation, or both. In one study, heterotropic gastric mucosa was found in 62% of cases, pancreatic tissue was found in 6%, both pancreatic tissue and gastric mucosa were found in 5%, jejunal mucosa was found in 2%, Brunner tissue was found in 2% and both gastric and duodenal mucosa were found in 2%. [2] Rarely, colonic, rectal, endometrial, and hepatobiliary tissues have been noted.

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Epidemiology

Frequency

United States

The prevalence of Meckel diverticulum is usually noted to be approximately 2% of the population, [4] but published series range from 0.2-4%. [5] Complications are only seen in about 5% of those with the anomaly. In a retrospective survey of 43 children's hospitals in the United States, 815 children had a Meckel diverticulectomy during a 2-year span. Slightly more than half (60%) were symptomatic and the remainder were incidental in children who had laparotomy for a different reason. [6]

International

Prevalence figures similar to those found in the United States have been reported in Europe and Asia.

Mortality/Morbidity

See Complications.

Race

One study investigated the Pediatric Hospital Information System (PHIS) database to identify demographics of patients with ICD-9 diagnoses of Meckel diverticulum and a procedure code for Meckel diverticulectomy. Data from a 9-year period (2004-2012) was analyzed for age, payer, ethnicity and symptoms. The database included patients admitted to 44 children’s hospitals in the United States. The ethnic distribution of symptomatic Meckel diverticulum was 63.4% white, 4.7% African-American, 16.4% Hispanic, 3.9% Asian, and 11.6% other. [7]

Sex

Although no sex-based difference was reported in studies that evaluated this condition as an incidental finding during operations or autopsies, males are as much as 3-4 times more prone to complications than females. In a large series of cases from 2007-2008, Meckel diverticulectomy was 2.3 times more common in boys and boys accounted for 74% of the primary cases. [6]

Age

The classic presentation in children is considered to be painless rectal bleeding in a toddler younger than 2 years. One large series found that 53% had surgery before their fourth birthday. However, the largest group (slightly more than 30%) were younger than one year. [6] Although most other pediatric cases occur in patients aged 2-8 years, many continue to present with hematochezia.

Although younger children have been reported to usually present with hematochezia and adults with obstruction, the same recent series of 815 pediatric (<8 y) cases found that a primary diverticulectomy was performed more commonly (30%) for obstruction, than bleeding (27%) and that a substantial proportion (19%) had intussusception [6] About one quarter did not have a clear cut diagnosis.

A recent literature review of Meckel Diverticulum in the neonatal period found that the most common manifestations in this age were bowel obstruction (58.3%) and pneumoperitoneum (33.3%). In addition, in both term and preterm neonates, males were even more frequently affected than females, with a male-to-female ratio of 6.5:1. Other neonatal presentations include perforation, intussusception, segmental ileal dilation, ileal volvulus, and massive hematochezia. [6]

In adults, obstruction and inflammation are more common presentations than lower GI bleeding. Several population-based studies have reported a decreased incidence of complications with increasing age, although other studies have not. Therefore, the issue of incidental diverticulectomy in older patients remains controversial.

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