Meckel’s Diverticulum - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x 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 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons Figure 1A Meckel’s diverticulum identified intra-operatively The Rule of 2s The Rules of 2s has been introduced to describe key facts about Meckel’s Diverticulum: Present in around 2% of the population Around 2 feet proximal to the ileocaecal valve Approximately 2 inches in length Can contain 2 types of ectopic tissue, gastric and pancreatic 2 times more common in males than in females 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 <https://creativecommons.org/licenses/by-sa/4.0> and Pc 75au, CC BY-SA 4.0 <https://creativecommons.org/licenses/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. Key Points A Meckel’s diverticulum occurs as a result of the incomplete obliteration of the vitelline duct during embryonic development The majority of the affected population who have a Meckel’s diverticulum will remain asymptomatic The majority of patients with a Meckel’s diverticulum will present acutely, either with bleeding or diverticulitis Those with Meckel’s diverticulitis will often require an urgent Meckel’s diverticulectomy Frequent questions What is Meckel’s diverticulum? Meckel’s diverticulum is a congenital anomaly of the gastrointestinal tract, characterised by an outpouching on the anti-mesenteric border of the ileum. It results from the incomplete obliteration of the vitelline duct during embryonic development. What are the clinical features of Meckel’s diverticulum? Most individuals with Meckel’s diverticulum remain asymptomatic throughout their lives. However, some may experience complications such as per rectal bleeding or abdominal pain due to diverticulitis, which can mimic acute appendicitis. How is Meckel’s diverticulum diagnosed? Diagnosis typically occurs when patients present with acute symptoms, often through CT imaging or during surgical exploration. In outpatient settings, nuclear scintigraphy using technetium-99m can help visualise the diverticulum by highlighting ectopic gastric mucosa. What management options are available for Meckel’s diverticulitis? Patients with Meckel’s diverticulitis usually require urgent surgical intervention, often through a Meckel’s diverticulectomy. In cases involving perforation or bowel obstruction, a small bowel resection may be necessary to remove affected bowel sections. What is the significance of the "Rule of 2s" in relation to Meckel’s diverticulum? The "Rule of 2s" highlights key characteristics of Meckel’s diverticulum: it occurs in about 2% of the population, is typically located 2 feet from the ileocaecal valve, measures approximately 2 inches in length, and is more prevalent in males than females by a ratio of 2:1. Rate This Article