Meckel’s Diverticulum

Introduction

A Meckel’s diverticulum is a congenital abnormality of the gastrointestinal tract*, whereby an outpouching (a diverticulum) develops on the anti-mesenteric border of the ileum (Fig. 1)

The vitelline duct normally serves as a connection between the yolk sac and the small intestine during embryonic development, appearing at the end of the fourth week and normally has obliterated (narrows and disappears) by the ninth week.

Meckel’s diverticulum occur as a result of the incomplete obliteration of the vitelline duct during embryonic development.

*It is considered a true diverticulum as it contains all the layers of the small intestine

Milliways, CC BY-SA 3.0 , via Wikimedia Commons

Figure 1 – A Meckel’s diverticulum identified intra-operatively

Clinical Features

The majority of the affected population who have a Meckel’s diverticulum will remain asymptomatic for all their life, not presenting with any symptoms or causing any problems

For the small proportion of affected individuals, ectopic mucosa within the diverticulum can result in inflammation or ulceration of the involved and surrounding mucosa.

This can most commonly result in either per rectal bleeding (typically dark red in colour, most common in children) or abdominal pain (due to diverticulitis). Indeed, Meckel’s diverticulitis, inflammation of the diverticulum, can present similarly to an acute appendicitis with periumbilical pain, tenderness, and vomiting.

Less commonly, Meckel’s diverticulum can result in bowel obstruction*, due to adhesional band formation or intussusception of the small bowel (with the diverticulum acting as the lead point).

*A Meckel’s diverticulum present is an abdominal wall hernia is termed a Littre hernia

Investigation

The majority of patients with a Meckel’s diverticulum will present acutely, either with bleeding or diverticulitis. This will be identified either on CT imaging pre-operatively or intra-operatively at diagnostic laparoscopy or laparotomy (Fig. 1)

For those being diagnosed in the outpatient setting, nuclear scintigraphy is the mainstay of investigation, specifically with technetium-99m nucleotide. This is absorbed by the ectopic gastric mucosa of the Meckel’s diverticulum to allow for its visualisation (Figure 2A).

Less commonly, a CT angiogram may identify an anomalous branch from the superior mesenteric artery feeding into the diverticulum (Figure 2B) to allow for its identification.

Adapted from JasonRobertYoungMD, CC BY-SA 4.0 and Pc 75au, CC BY-SA 4.0 , via Wikimedia Commons

Figure 2 – (A) Scintigraphy of Meckel’s diverticulum, showing ectopic gastric tissue in right lower quadrant of the abdomen (B) an angiogram showing the vasculature of a Meckel’s diverticulum

Management

Those with Meckel’s diverticulitis will often require urgent surgery, whereby a Meckel’s diverticulectomy can be performed, which can be performed either open or laparoscopically. In cases of perforation or those with bowel obstruction, a small bowel resection may be required, to remove the surrounding bowel as well.

Those presenting with PR bleeding should be approached initially as with any case of PR bleeding, considering interventional radiology if appropriate. However, if not performed acutely, an outpatient diverticulectomy should be performed.