Meckel's diverticulum

Congenital anomaly of the gastrointestinal tract

Meckel's diverticulum is a congenital anomaly of the gastrointestinal tract that results from an incomplete obliteration of the vitelline duct (also known as the omphalomesenteric duct) during embryonic development. It is the most common congenital defect of the gastrointestinal tract, occurring in approximately 2% of the population.

Anatomy and Pathophysiology

Illustration of Meckel's diverticulum

Meckel's diverticulum is a true diverticulum, meaning it contains all layers of the intestinal wall, including the mucosa, submucosa, and muscularis propria. It is typically located in the ileum, about 40 to 100 cm proximal to the ileocecal valve. The diverticulum is usually 3 to 5 cm in length, but it can vary significantly.

The presence of ectopic tissue, such as gastric mucosa or pancreatic tissue, within the diverticulum can lead to complications. Gastric mucosa can secrete acid, leading to ulceration and bleeding.

Clinical Presentation

Pathological specimen of Meckel's diverticulum

Most individuals with Meckel's diverticulum are asymptomatic. However, when symptoms do occur, they often present in childhood. The classic presentation includes painless rectal bleeding, which may be due to ulceration of the ectopic gastric mucosa.

Other potential complications include intestinal obstruction, volvulus, and intussusception. Inflammation of the diverticulum, known as Meckel's diverticulitis, can mimic appendicitis.

Diagnosis

Meckel's diverticulum as seen on a technetium-99m pertechnetate scan

The diagnosis of Meckel's diverticulum can be challenging, especially in asymptomatic individuals. When symptomatic, a technetium-99m pertechnetate scan (Meckel's scan) is often used to detect ectopic gastric mucosa. This scan is particularly useful in children presenting with unexplained gastrointestinal bleeding.

Other diagnostic modalities include CT scan, MRI, and endoscopy, although these are less specific.

Treatment

File:Cck1.png

Surgical resection of Meckel's diverticulum

The treatment of Meckel's diverticulum depends on the presence and type of symptoms. Asymptomatic diverticula are often left untreated. However, symptomatic diverticula, especially those causing bleeding or obstruction, typically require surgical intervention.

Surgical options include diverticulectomy, where only the diverticulum is removed, or segmental resection, where a portion of the ileum is removed along with the diverticulum.

Prognosis

The prognosis for individuals with Meckel's diverticulum is generally excellent, especially when complications are promptly addressed. Surgical treatment of symptomatic diverticula usually results in complete resolution of symptoms.

Related pages

• Appendicitis
• Intestinal obstruction
• Gastrointestinal bleeding