Basics
Description
- 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 population
- Male-to-female ratio 2:1
- Within 2 feet of the ileocecal valve
- Can be up to 2 inches in length
- Symptoms 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 fistula
- Omphalomesenteric cyst
- Fibrous 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 malformations
- Exophthalmos
- Cleft palate
- Annular pancreas
- Some 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 incidentally
- Sarcomas are the most common malignancy associated with MD, followed by carcinoids and adenocarcinomas.
Diagnosis
History
- Rectal bleeding
- In 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.
- Obstruction
- Partial or complete small bowel obstruction
- The 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 patients
- Intraperitoneal bands, volvulus, or internal herniation may also lead to an obstructive presentation.
- 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
- 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
- Inflammation (i.e., diverticulitis, ruptured diverticulum with peritonitis)
- Fever
- Abdominal tenderness
- Symptoms 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 diverticulum
- Sensitivity 85%, specificity 95% in children; considerably lower in adults
- Cimetidine can be used to increase retention of isotope within ectopic gastric mucosa.
- Mesenteric arteriography
- RBC scan with severe bleeding
Diagnostic Procedures/Other
- Surgery
- In 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
- Bleeding
- Address issues of anemia and volume status based on vital signs and blood tests.
- Obstruction
- Evaluate 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