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Meckel Diverticulum, Pediatric

Basics

Description

- True diverticulum (contains all 3 layers of the bowel wall) - Originates from the antimesenteric border of the bowel in the region of the terminal ileum and proximal to the ileocecal valve - Remnant of the omphalomesenteric (vitelline) duct which fails to involute completely during the 5th " 6th week of gestation as the placenta replaces the yolk sac as the source of fetal nutrition - MD accounts for 90% of the vitelline duct anomalies. Other anomalies include the following: - Omphalomesenteric fistula - Omphalomesenteric cyst - Fibrous band

- MD has also been associated with several other congenital anomalies that include the following: - Anorectal atresia (affects 11% of patients with MD) - Esophageal atresia (12%) - Minor omphalocele (25%) - Cardiac malformations - Exophthalmos - Cleft palate - Annular pancreas - Some central nervous system malformations

- Inflammation/fever - Another common presentation for symptomatic MD is inflammation or diverticulitis, which can occur in 12 " 40% of cases. - Patients often present with signs and symptoms consistent with appendicitis, and the diagnosis is made at the time of surgical exploration. - In a subset of this group (~1/3), the diverticulum may perforate from infarction or ulceration and lead to a more acute and toxic presentation.

- Physical exam may be normal but will often reflect the type of presenting complication: - Bleeding - Tachycardia - Hypotension - Blood in the stool - Hyperactive bowel sounds

- Obstruction - Abdominal pain - Vomiting - Bilious emesis - Abdominal distention

- Meckel scan (technetium-99m pertechnetate scan) - Evaluates for ectopic gastric mucosa within the diverticulum - Sensitivity 85%, specificity 95% in children; considerably lower in adults - Cimetidine can be used to increase retention of isotope within ectopic gastric mucosa.

  • Meckel diverticulum (MD) is the most common congenital abnormality of the GI tract.
  • Derives from the omphalomesenteric duct remnants
  • The most common clinical presentation in children of MD is painless rectal bleeding.
  • Classically characterized by "Rule of 2 's "Present in approximately 2% of the populationMale-to-female ratio 2:1Within 2 feet of the ileocecal valveCan be up to 2 inches in lengthSymptoms usually present by 2 years of age.

Epidemiology

  • MD as an anomaly occurs in ~2% of the population, but only ~4% of patients with MD develop symptoms over their lifetime.
  • MD is more common in patients with other malformations including anorectal atresia, esophageal atresia, omphalocele, and cardiac abnormalities.
  • MD is considered to be more common in males, with a male/female ratio of 2:1.
  • Males are also more likely to have symptomatic diverticula.

Pathophysiology

  • Diverticula with ectopic tissue are more likely to be symptomatic.
  • Ectopic tissue in MD is often of gastric origin; can also be comprised pancreatic, duodenal, or colonic tissue as well
  • Bleeding occurs when gastric mucosa is present, resulting in peptic ulcerations of the small bowel downstream from the diverticulum (90% of cases).
  • Alkaline secretions from ectopic pancreatic tissue can also cause ulcerations with bleeding.
  • Obstruction can occur when the diverticulum acts as a lead point for intussusception, when the diverticulum becomes inflamed with subsequent lumen narrowing, or when the diverticulum induces a volvulus.

Etiology

  • True diverticulum (contains all 3 layers of the bowel wall)
  • Originates from the antimesenteric border of the bowel in the region of the terminal ileum and proximal to the ileocecal valve
  • Remnant of the omphalomesenteric (vitelline) duct which fails to involute completely during the 5th " 6th week of gestation as the placenta replaces the yolk sac as the source of fetal nutrition
  • MD accounts for 90% of the vitelline duct anomalies. Other anomalies include the following:Omphalomesenteric fistulaOmphalomesenteric cystFibrous band

Commonly Associated Conditions

  • MD has also been associated with several other congenital anomalies that include the following:Anorectal atresia (affects 11% of patients with MD)Esophageal atresia (12%)Minor omphalocele (25%)Cardiac malformationsExophthalmosCleft palateAnnular pancreasSome central nervous system malformations
  • Malignancies have also been reported in association with MD.Can be present within the diverticulum and can cause obstructive symptoms or can be found incidentallySarcomas are the most common malignancy associated with MD, followed by carcinoids and adenocarcinomas.

Diagnosis

History

  • Rectal bleedingIn children, the most common presentation is with painless rectal bleeding, which may range from occult blood to frank bright red blood and hemodynamic instability.The bleeding tends to be self-limiting, because of constriction of the splanchnic vessels secondary to hypovolemia.Bleeding is most commonly seen in children <5 years of age.
  • ObstructionPartial or complete small bowel obstructionThe clinical symptoms in this setting include recurrent abdominal pain, abdominal distention, nausea, and vomiting.Most common type of presentation in adults and can occur in up to 40% of pediatric patientsIntraperitoneal bands, volvulus, or internal herniation may also lead to an obstructive presentation.
  • Inflammation/feverAnother common presentation for symptomatic MD is inflammation or diverticulitis, which can occur in 12 " 40% of cases.Patients often present with signs and symptoms consistent with appendicitis, and the diagnosis is made at the time of surgical exploration.In a subset of this group (~1/3), the diverticulum may perforate from infarction or ulceration and lead to a more acute and toxic presentation.

Physical Exam

  • Physical exam may be normal but will often reflect the type of presenting complication:BleedingTachycardiaHypotensionBlood in the stoolHyperactive bowel soundsObstructionAbdominal painVomitingBilious emesisAbdominal distentionInflammation (i.e., diverticulitis, ruptured diverticulum with peritonitis)FeverAbdominal tendernessSymptoms more consistent with acute abdomen

Diagnostic Tests & Interpretation

  • The diagnosis of symptomatic MD is difficult to make and requires a high index of suspicion.
  • This diagnosis should be considered in any patient with recurrent unexplained abdominal pain, nausea and vomiting, or rectal bleeding.

Lab

  • The diagnosis of MD cannot be made with laboratory evaluation or plain radiography alone.
  • Laboratory analysis may be helpful to determine the degree of bleeding, with a hemoglobin count and a coagulation profile to rule out an underlying coagulopathy.
  • Plain radiographs may show evidence of obstruction but are not diagnostic of MD.

Imaging

  • Meckel scan (technetium-99m pertechnetate scan)Evaluates for ectopic gastric mucosa within the diverticulumSensitivity 85%, specificity 95% in children; considerably lower in adultsCimetidine can be used to increase retention of isotope within ectopic gastric mucosa.
  • Mesenteric arteriography
  • RBC scan with severe bleeding

Diagnostic Procedures/Other

  • SurgeryIn situations in which the Meckel scan is nondiagnostic or in patients with nonbleeding symptoms (but when there is a high index of suspicion for MD), exploratory laparoscopy may be indicated.
  • Capsule endoscopy and balloon enteroscopy can establish the diagnosis but are not routinely used.

Differential Diagnosis

  • Allergic colitis
  • Infectious colitis
  • Polyps
  • Inflammatory bowel disease
  • Angiodysplasia
  • Constipation/anorectal fissure
  • Coagulopathy
  • Henoch-Sch ¶nlein purpura
  • Intussusception
  • Lymphonodular hyperplasia
  • Intestinal duplication

Treatment

The treatment for MD that are symptomatic and identified is surgical removal. Surgery involves diverticulectomy or partial bowel resection.

Surgery/Other Procedures

  • Initial management should include supportive care.
  • Correct any electrolyte abnormalities.
  • Initiate proton pump inhibitor (PPI) for gastrointestinal bleeding (PPI will not affect the results of the Meckel scan).
  • Nasogastric tube placement for decompression of bowel obstruction
  • Surgical intervention of an incidentally found MD is controversial.If it is found during surgical exploration, intervention depends on the size of the diverticulum, age of the patient, and whether fibrous bands are present.If it is found incidentally during radiologic imaging, symptoms should be monitored closely, but most do not recommend elective surgery.

Inpatient Considerations

Initial Stabilization

  • BleedingAddress issues of anemia and volume status based on vital signs and blood tests.
  • ObstructionEvaluate the need for acute management (surgical) and decompression.

Additional Reading

  • McCollough M, Sharieff GQ. Abdominal surgical emergencies in infants and young children. Emerg Med Clin North Am. 2003;21(4):909 " 935. [View Abstract]
  • Mendelson KG, Bailey BM, Balint TD, et al. Meckel diverticulum: review and surgical management. Curr Surg. 2001;58(5):455 " 457. [View Abstract]
  • Ruscher KA, Fisher JN, Hughes CD, et al. National trends in the surgical management of Meckel 's diverticulum. J Pediatr Surg. 2011;46(5):893 " 896. [View Abstract]
  • Shalabi RY, Soliman SM, Fawy M, et al. Laparoscopic management of Meckel 's diverticulum in children. J Pediatr Surg. 2005;40(3):562 " 567. [View Abstract]
  • Snyder CL. Current management of umbilical abnormalities and related anomalies. Semin Pediatr Surg. 2007;16(1):41 " 49. [View Abstract]
  • Tseng YY, Yang YJ. Clinical and diagnostic relevance of Meckel 's diverticulum in children. Eur J Pediatr. 2009;168(12):1519 " 1523. [View Abstract]
  • Uppal K, Tubbs RS, Matusz P, et al. Meckel 's diverticulum: a review. Clin Anat. 2011;24(4):416 " 422. [View Abstract]

Codes

ICD09

  • 751.0 Meckel 's diverticulum

ICD10

  • Q43.0 Meckel 's diverticulum (displaced) (hypertrophic)

SNOMED

  • 37373007 Meckel 's diverticulum (disorder)

FAQ

  • Q: What are various indications for resection of a Meckel diverticulum?
  • A: Intussusception, narrowing at base of diverticulum, or presence of ectopic tissue resulting in bleeding
  • Q: What is the most common type of ectopic tissue present in Meckel diverticulum?
  • A: Gastric
  • Q: What is the most common presentation of a Meckel diverticulum?
  • A: Intermittent, painless rectal bleeding