Meckel diverticulum
Updates to Article Attributes
Meckel diverticulum is a type of congenital intestinal diverticulum that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract.
Epidemiology
Approximately 2% (range 0.3-3%) 11 of all individuals may have a Meckel diverticulum (see the Rule of 2s). While traditionally described to have increased male predilection, it may occur with equal frequency in both sexes although symptoms from complications are more common in male patients 2,11. Most patient with a complication are thought to present before the 1st two years of age 11.
Clinical presentation
A large proportion of individuals remain asymptomatic although up to a third of them may experience clinical symptoms 1. Clinical presentation includes:
- pain
- malaena/haematochezia
- small bowel obstruction
- intussusception
- volvulus
- perforation
- Littre hernia
Gross anatomy
Meckel diverticulum is a true diverticulum (i.e. all layers of gastrointestinal tract are present in its wall) and arises from the antimesenteric border of small intestine.
It can be as long as 10 cm with diameters up to 2 cm. Most (75%) Meckel diverticula are found within 100 cm (two feet) of the ileocecal valve 2. It can be seen in the midline, or on either side of midline. However, midline and right iliac fossa location is commoner. Its level on CT can be either superior or inferior to terminal ileum 1.
Blood supply
- typically arises from the omphalomesenteric artery (arising from an ileal branch of the superior mesenteric artery)
Histology
Meckel diverticula are lined with heterotopic mucosa in up to 60% of cases:
- gastric mucosa ~62%
- pancreatic ~6%
- gastric and pancreatic ~5%
- jejunal ~2%
- Brunner glands ~2%
- gastric and duodenal ~2%
Embryology
It is considered a remnant of the omphalomesenteric-vitelline duct, which connects the yolk sac to the midgut through the umbilical cord. This duct is typically obliterated by the 5-8th week of gestation. Failure of closure results in:
- diverticulum (~90% of cases)
- omphalomesenteric fistula
- enterocyst
- fibrous band
Radiographic features
Imaging these may be occasionally detected incidentally or may be identified if there is complication.
Fluoroscopy
Small bowel enemas have been sometimes used the diagnosis in some centres, although meticulous technique is required if the diagnosis is to be excluded with any degree of certainty 4.
Ultrasound
Usually of limited in diagnosis of an uncomplicated Meckel diverticulum. Ultrasound may show a blind ending peristaltic loop connected to small bowel.
CT
CT again a limited value in uncomplicated cases, as the diverticulum may resemble a normal bowel loop. CT may show a fluid or air-filled blind-ending pouch that arises from the antimesenteric side of the distal ileum.
Angiography or CT angiography
When investigated in the context of gastrointestinal haemorrhage angiography/CT angiography may show the persistent omphalomesenteric artery in most individuals with a Meckel diverticulum although recognition of the artery may be difficult due to overlying vessels.
Scintigraphy
Scintigraphy with 99mTc-Na-pertechnetate has a limited sensitivity (~60%) 2,9. It however aids in the diagnosis of diverticula with ectopic gastric mucosa. Pertechnetate is taken up by mucin-secreting cells of the gastric mucosa and ectopic gastric tissue. Higher sensitivity may be present in children (~85-90%).
Treatment and prognosis
Complications
The incidence of complications with a Meckel diverticulum are reported to widely range between 4% and 40% of patients 2-3:
- inflammation (diverticulitis): Meckel diverticulitis
- gastrointestinal haemorrhage: may account for ~30% of symptomatic cases 2
- intussusception: particularly if the diverticulum inverts 5
- perforation
- small-bowel obstruction
- enterolith formation
- associated neoplasm arising in Meckel diverticula
History and etymology
It is named after named after Johann Friedrich Meckel, who described its anatomy and embryology in 1809 2.
-<p><strong>Meckel diverticulum</strong> is a type of congenital intestinal diverticulum that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract.</p><h4>Epidemiology</h4><p>Approximately 2% (range 0.3-3%) <sup>11</sup> of all individuals may have a Meckel diverticulum. While traditionally described to have increased male predilection, it may occur with equal frequency in both sexes although symptoms from complications are more common in male patients <sup>2,11</sup>. Most patient with a complication are thought to present before the 1<sup>st</sup> two years of age <sup>11</sup>.</p><h4>Clinical presentation</h4><p>A large proportion of individuals remain asymptomatic although up to a third of them may experience clinical symptoms<sup> 1</sup>. Clinical presentation includes:</p><ul>- +<p><strong>Meckel diverticulum</strong> is a type of congenital intestinal diverticulum that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract.</p><h4>Epidemiology</h4><p>Approximately 2% (range 0.3-3%) <sup>11</sup> of all individuals may have a Meckel diverticulum (see the <a title="Rule of 2s" href="/articles/rule-of-2s">Rule of 2s</a>). While traditionally described to have increased male predilection, it may occur with equal frequency in both sexes although symptoms from complications are more common in male patients <sup>2,11</sup>. Most patient with a complication are thought to present before the 1<sup>st</sup> two years of age <sup>11</sup>.</p><h4>Clinical presentation</h4><p>A large proportion of individuals remain asymptomatic although up to a third of them may experience clinical symptoms<sup> 1</sup>. Clinical presentation includes:</p><ul>
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