A Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract and is caused by an incomplete obliteration of the omphalomesenteric duct. It is generally about 2 inches long and located 2 feet proximal to the ileocecal valve. It is seen in 2% of the general population and is more common in males. The mucosal lining of the diverticulum may be either native ileal mucosa or heterotopic mucosa (most commonly gastric). It is often asymptomatic and detected incidentally on imaging or abdominal surgery. The characteristic presentation of symptomatic Meckel diverticulum is painless lower gastrointestinal bleeding (hematochezia) in children < 2 years. Patients may also present with acute intestinal obstruction (intussusception or volvulus), diverticulitis, and, rarely, peritonitis due to perforation of a Meckel diverticulum. A Meckel diverticulum should be suspected when the work-up of a patient with lower gastrointestinal bleed or acute abdomen reveals no abnormalities. Sensitive and specific diagnostic tests for Meckel diverticulum include Meckel scan (99m technetium scintigraphy), CT angiography, and diagnostic laparoscopy. All symptomatic/complicated cases of Meckel diverticulum must be surgically resected. An asymptomatic Meckel diverticulum detected incidentally during abdominal surgery in a child should be resected. In adults < 50 years, only an incidentally detected Meckel diverticulum with risk factors for complications (e.g., a long, broad-based diverticulum) should be resected. An asymptomatic Meckel diverticulum incidentally detected on imaging does not require treatment.
The omphalomesenteric (vitelline or vitellointestinal) duct is a patent tubular structure connecting the yolk sac to the alimentary tract in the embryo.
The duct is normally obliterated by the 6th week of intrauterine life.
Meckel diverticulum is a true diverticulum.
The rule of two's: Meckel diverticulum occurs in 2% of the population, 2% are symptomatic, mostly in children < 2 years, affects males twice as often as females, is located 2 feet proximal to the ileocecal valve, is ≤ 2 inches long, and can have 2 types of mucosal lining.
Symptomatic (2–4%) A Meckel diverticulum with a length > 2 cm, a broad base (> 2 cm), heterotopic mucosa (esp. gastric), and/or a fibrous band connecting the diverticulum to the umbilicus is at a higher risk of becoming symptomatic.
The initial work-up follows the same protocol as that for lower gastrointestinal bleeding and/or acute abdomen. Only the imaging tests specific to Meckel diverticulum are mentioned here.
Diverticulectomy: Meckel diverticulum is resected at the base.
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