Meckel Diverticulum
Meckel Diverticulum: Excerpt from The 5-Minute Pediatric Consult
Edisio Semeao, MD
Meckel Diverticulum - BASICS
Meckel Diverticulum - description
- Meckel diverticulum is the most common congenital abnormality of the GI tract.
- A congenital anomaly that is part of the group known as the omphalomesenteric duct remnants
- In pediatric patients, the most common clinical presentation is with painless rectal bleeding.
- Other symptoms that may also be described include recurrent abdominal pain, abdominal distention, nausea, and/or vomiting.
Meckel Diverticulum - epidemiology
- Meckel diverticulum was 1st described by Johann Meckel in 1809.
- A remnant of the embryonic yolk sac found in ~2% of all infants
- Although the presence of Meckel diverticulum is 2% in the population, the rarity of this anomaly in clinical practice is that only 4–6.5% of patients are symptomatic.
- The development of symptoms seems to be age related, with the peak incidence being early childhood (2 years).
- 80% of all patients requiring surgery were <10 years of age, and nearly 50% were <2 years of age.
Meckel Diverticulum - incidence
- Meckel diverticulum tends to be more common in males with a male/female ratio of 3:2, and also with males having more symptomatic diverticula.
- These have also been associated with several other congenital anomalies that include:
- Anorectal atresia (11%)
- Esophageal atresia (12%)
- Minor omphalocele (25%)
- Cardiac malformations
- Exophthalmos
- Cleft palate
- Annular pancreas
- Some central nervous system malformations
Meckel Diverticulum - pathophysiology
- Meckel diverticulum is a true diverticulum containing all 3 layers of the bowel wall, and its vascular supply comes from a remnant of the vitelline artery.
- Most of these diverticula are lined with ileal mucosa, but ectopic tissue is often present.
- ~50% of diverticula contain ectopic tissue.
- Gastric tissue accounts for 60–85%.
- Pancreatic tissue accounts for 5–16%.
- Other less common tissue types include colonic and duodenal.
- Of the symptomatic cases of Meckel diverticulum, 40–80% have some type of ectopic tissue, with the most common being gastric or pancreatic type.
Meckel Diverticulum - etiology
- This abnormality results from the incomplete obliteration of the fetal omphalomesenteric (vitelline) duct between the 7th and 8th week of gestation.
- The vitelline duct communicates with the yolk sac and involutes as the placenta replaces the yolk sac as the source of fetal nutrition. Failure of this process results in various anomalies; Meckel diverticulum accounts for 90% of the vitelline duct anomalies.
- This diverticulum originates from the antimesenteric border of the bowel in the region of the terminal ileum and proximal to the ileocecal valve. It can be between 3 and 6 cm in length.
- Other intestinal diverticula are more common in the jejunum and on the mesenteric border of the bowel.
Meckel Diverticulum - associated conditions
Malignancies have also been reported in association with Meckel diverticulum. These are present within the diverticulum and can cause obstructive symptoms or can be found incidentally.
- Sarcomas are most common, followed by carcinoids and adenocarcinomas.
Meckel Diverticulum - DIAGNOSIS
Meckel Diverticulum - signs & symptoms
- Rectal bleeding
- Obstruction—Abdominal pain/vomiting
- Inflammation—Fever
Meckel Diverticulum - history
- 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.
- Bleeding is thought to occur due to the highly acidic secretions of the gastric tissue on the adjacent tissues which may cause ulcerations that leads to bleeding. Similarly, the alkaline secretions of the pancreatic tissue may also cause ulcerations and lead to bleeding.
- The bleeding, even in the most severe cases, 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. In diverticula that bleed, 90% have ectopic gastric mucosa.
- Obstruction:
- Partial or complete small-bowel obstruction
- The clinical symptoms in this setting include recurrent abdominal pain, abdominal distention, nausea, and vomiting.
- This is the most common type of presentation in adults and can also occur in up to 40% of pediatric patients. It results from intussusception, in which the Meckel diverticulum serves as a lead point.
- Intraperitoneal bands, volvulus, or internal herniation may also lead to an obstructive presentation.
- Inflammation/Fever:
- Another common presentation for symptomatic Meckel diverticulum is inflammation/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.
Meckel Diverticulum - physical exam
- Physical exam findings are variable and are dependent upon the type of presenting complications.
- In children with rectal bleeding, the exam is usually benign except for a positive rectal exam and usually low BP and tachycardia.
- Patients with obstructive symptoms may have abdominal distention and tenderness and hyperactive bowel sounds.
- Patients with an inflammatory (diverticulitis) type of presentation will have findings similar to those in appendicitis, with the possibility of peritoneal signs in cases of perforation.
Meckel Diverticulum - tests
- The diagnosis of symptomatic Meckel diverticulum 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.
Meckel Diverticulum - lab
- The diagnosis cannot be made with laboratory evaluation or plain radiography.
- Laboratory analysis may be helpful to determine the degree of bleeding with a hemoglobin count and a coagulation profile to rule out an underlying bleeding disorder.
- Plain radiographs may show evidence of obstruction, but are not diagnostic of Meckel diverticulum.
Meckel Diverticulum - imaging
- Contrast studies such as upper gastrointestinal series with small bowel follow-through or enteroclysis studies are limited in value because the layers of barium in the bowel can obscure the diverticulum.
- CT scan and ultrasound are often nonspecific in diagnosis but can be helpful in looking for other causes of presenting symptoms.
- Endoscopy and colonoscopy are not sensitive for the diagnosis but can be helpful in identifying other causes that may explain symptoms.
- Angiography may not be helpful because the vascular supply is usually normal.
- Red cell–tagged scans are not specific for Meckel diverticulum, but may be useful in localizing the site of bleeding.
Meckel Diverticulum - diag proced-surgery
- The most useful method of diagnosis of Meckel diverticulum is with a Meckel scan (technetium-99m pertechnetate scan).
- This technique, however, depends on the presence of ectopic gastric mucosa within the diverticulum to have uptake of the isotope by the gastric mucosa. Because not all diverticula contain gastric mucosa, this scan may not be of value in all situations.
- However, because complications such as bleeding are usually (90%) associated with ectopic gastric tissue, this test may be diagnostic in many symptomatic cases.
- In children, the scan has a sensitivity and specificity of 85% and 95%, respectively, but in adults these values fall to 62.5% and 9%, respectively.
- Technetium-99m pertechnetate is taken up by the ectopic gastric tissue (mucous neck secreting cells). Certain substances enhance the detection of the ectopic gastric tissue, including cimetidine, glucagon, and pentagastrin.
- False results can occur in 20% of the scans.
- False-positive with bleeding: Intussusception, hemangioma, arteriovenous malformation (AVM), inflammatory lesion, Crohn disease, peptic ulcer, carcinoid and uterine fibroids
- False-positive without bleeding: Ureteral obstruction, sacral meningomyelocele
- False-negative: Barium, bladder overdistention, no gastric mucosa present
- 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 Meckel diverticulum), laparoscopy has been shown to be effective and have less morbidity than an exploratory laparotomy.
Meckel Diverticulum - differencial diagnosis
Based on the 2 main clinical symptoms:
- Bleeding:
- Rectal fissure
- Polyps
- Allergic proctitis
- Infectious colitis
- Lymphonodular hyperplasia
- AVM
- Hirschsprung enterocolitis
- Peptic ulcer disease
- Inflammatory bowel disease
- Hemolytic uremic syndrome
- Henoch-Schönlein purpura
- Obstruction:
- Appendicitis
- Intussusception
- Malrotation/Volvulus
- Intestinal duplication
- Colonic diverticulitis
- Adhesions/Strictures
Meckel Diverticulum - TREATMENT
Meckel Diverticulum - 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.
Meckel Diverticulum - general measures
The treatment for Meckel diverticula that are symptomatic and identified is surgical removal.
Meckel Diverticulum - surgery
- Surgical resection can be done with simple diverticulectomy, but in cases in which the adjunct ileum is damaged or there is further evidence of ectopic tissue, a limited resection may be required.
- The bigger dilemma is what should be the approach when a Meckel diverticulum is found incidentally and the patient is asymptomatic.
- Previous research had indicated that the morbidity for diverticulectomy is ~9% and that, because the risk of developing symptoms in a lifetime was 4%, these diverticula should be left in place. More recent work has shown a much lower morbidity (2%) associated with the removal of the diverticulum; thus, some researchers have advocated removal of the diverticulum that is found incidentally.
- The development of new techniques such as laparoscopy and stapling devices has aided in decreasing the morbidity and mortality in this procedure.
Meckel Diverticulum - FOLLOW UP
- There have been several series that have compared features of symptomatic versus asymptomatic diverticula to see if there are characteristics that would help in deciding the approach to asymptomatic diverticulum. If these features are noted, the risk of developing symptoms later in life if the diverticulum is not removed is significantly increased. These include:
- Age, younger patients (<8–10 years of age)
- Longer diverticulum (≥2 cm)
- Narrower base (≤2 cm in diameter)
Meckel Diverticulum - bibliography
- Bani-Hani K, Shatnawi N. Meckel diverticulum: Comparison of incidental and symptomatic cases. World J Surg. 2004;28(9):917–920.
- Cooney D, Duszynski D, Camboa E, et al. The abdominal technetium scan (a decade of experience). J Pediatr Surg. 1982;17:611–619.
- Mackey W, Dineen P. A fifty year experience with Meckel diverticulum. Surg Gynecol Obstet. 1983;156:56–64.
- McCollough M, Sharieff G. Abdominal surgical emergencies in infants and young children. Emerg Med Clin N Am. 2003;21(4):909–935.
- Mendelson K, Bailey B, Balint T, et al. Meckel diverticulum: Review and surgical management. Curr Surg. 2001;58(5):455–457.
- Shalabi R, Soliman S, Fawy M, et al. Laparoscopic management of Meckel diverticulum in children. J Pediatr Surg. 2005;40(3):562–567.
Meckel Diverticulum - CODES
Meckel Diverticulum - icd9
751.0 Meckel diverticulum
Meckel Diverticulum - FAQ
- Q: What are the reasons for resection of a Meckel diverticulum?
- A: Narrowing at base of diverticulum or presence of ectopic tissue resulting in bleeding.
- Q: What is the most common ectopic tissue present in Meckel diverticulum?
- A: Gastric
- Q: What is the most common presentation of a Meckel diverticulum?
- A: Intermittent, painless rectal bleeding
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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