Meckel's Diverticulitis

Aka: Meckel's Diverticulitis, Meckel's Diverticulum, Meckel Diverticulum

1. See Also
   1. Appendicitis
2. Epidemiology
   1. Most common cause of significant Gastrointestinal Bleeding in children
   2. Meckel's Diverticulum occurs equally in both genders
      1. Complications are more common in males by ratio of 3:2
   3. Lifetime complication rate: 4%
      1. More than 50% of complications occur before age 10
3. History
   1. Initial report by Hildanus in 1598
   2. Detailed description by Johann Meckel in 1809
4. Pathophysiology: Meckel's Diverticulum
   1. Meckel's Diverticulum is the most common congenital malformation of the gastrointestinal tract
   2. Incomplete closure of vitelline duct (omphalomesenteric remnant)
      1. Omphalomesenteric duct (vitelline duct) connects primitive gut to Yolk Sac in early fetal development
      2. Duct typically closes and obliterates when the placenta replaces the Yolk Sac at 7 weeks gestation
      3. Incomplete elimination of the Omphalomesenteric duct (vitelline duct) results in various remnants
         1. Meckel's Diverticulum
         2. Enterocyst
         3. Fibrous Cord
         4. Fistula
   3. Characteristics
      1. Meckel's Diverticulum contains all intestinal wall layers (serosa, muscle, submucosa, mucosa)
      2. Meckel's Diverticulum may be lined with gastric mucosa (85%) and other heterotopic tissue
         1. Ectopic tissue occurs most often at the diverticulum tip
         2. Gastric mucosa acid secretion may lead to ulceration, bleeding
         3. Other heterotopic tissue
            1. Pancreatic tissue
            2. Brunner's glands
            3. Duodenal mucosa
            4. Colonic mucosa
            5. Hepatobiliary mucosa
            6. Endometrial mucosa
      3. Blood supply is ultimately from superior Mesenteric Artery (derived from omphalomesenteric artery)
   4. Location
      1. Proximal to ileocecal valve by 100 cm
      2. Usually within 45 to 60 cm of ileocecal valve
   5. Follows the rule of 2's (roughly)
      1. Affects 2% of the population (range 0.4 to 4%)
      2. Often presents before age 2 years
      3. May contain two types of ectopic tissue, such as gastric (85%) and pancreatic tissue
      4. Symptomatic presentations or complications affect 2-4% of those with Meckel's Diverticulum
      5. If symptoms are to occur, they occur by age 2 years in 50% of cases (age 10 in some references)
      6. Occurs 2 feet (up to 100 cm) proximal to the ileocecal valve
      7. Meckel's Diverticulum is 2 cm wide and 2 cm long
5. Findings
   1. Episodic Rectal Bleeding
      1. Painless intermittent bleeding is the most common presentating symptom in children
      2. Bleeding may occur from ulceration of gastric or pancreatic ectopic tissue, or from intermittent intussception
   2. Acute Meckel's Diverticulitis and other complications (e.g. obstruction)
      1. Abdominal Pain
      2. Intractable Vomiting
      3. Tachycardia
6. Differential Diagnosis: Meckel's Diverticulitis
   1. See Appendicitis
   2. Viral Gastroenteritis
   3. Constipation
   4. Intussusception
   5. Inflammatory Bowel Disease
7. Complications: Meckel's Diverticulum
   1. Meckel's Diverticulum has an overall complication rate of 4%
   2. GI Bleeding (25-50% of complications)
      1. Often associated with ectopic gastric mucosa
      2. Profuse Hemorrhage may occur
      3. Hemorrhage is most common presentation under age 2
      4. Resolves spontaneously in most cases
   3. Meckel's Diverticulitis (10 to 20% of complications)
      1. Similar in presentation to Appendicitis
   4. Bowel Obstruction (14 to 53% of cases, esp. adults)
      1. Volvulus at fibrotic band attached to abdominal wall
      2. Intussusception
      3. Incarcerated Inguinal Hernia (Littre's Hernia)
   5. Bowel Perforation
   6. Malignancy
      1. Carcinoid Tumor
      2. Sarcoma
      3. Stromal Tumor
      4. Intraductal Papillary Mucinous Adenoma of Pancreatic Tissue
      5. Miscellaneous tumors and adenocarcinomas
8. Imaging
   1. Radionuclide Scintigraphy (Meckel's Scan)
      1. Performed via IV injection of Sodium Tc-pertechnetate
      2. Preferential uptake by gastric tissue
         1. Detects ectopic gastric mucosa
      3. Most accurate test in Meckel's Diverticulum
         1. Test Sensitivity: 85% in children
         2. Test Specificity: 95% in children
      4. Less accurate in adults
         1. Cimetidine increases accuracy in adults
   2. Small Bowel enema
      1. Indicated for negative scintigraphy in adults
   3. Arteriography (indicated for acute Hemorrhage)
   4. Tests to evaluate differential diagnosis (but not typically useful in diagnosis of Meckel's Diverticulum or Diverticulitis)
      1. Abdominal XRay
      2. Abdominal Ultrasound
         1. May show blind-ended thick-walled loop eminating from Small Bowel
         2. Evaluates for other diagnosis (e.g. intussception, Appendicitis)
      3. CT Abdomen and Pelvis with oral and IV contrast
         1. Excludes other Abdominal Pain causes (e.g. Appendicitis, Small Bowel Obstruction)
         2. Meckel's Diverticulum or Diverticulits is missed unless perforation or other complications are present
9. Evaluation
   1. Maintain a high index of suspicion
      1. Delayed diagnosis is common
10. Management: Meckel's Diverticulum
    1. Symptomatic (e.g. Meckel's Diverticulitis)
       1. Prompt surgical resection of Meckel's Diverticulum
       2. Segmental bowel resection indications
          1. Perforation
          2. Intestinal Ischemia
          3. Ectopic tissue extends to diverticulum junction or into intestinal mucosa
    2. Asymptomatic incidental finding on other surgery
       1. Resect all symptomatic cases (as above)
       2. Prophylactic resection of Meckel's Diverticulum indications
          1. Age <8 years old (some guidelines recommend <40 years old)
          2. Male gender (higher complication rate)
          3. Meckel's Diverticulum >2 cm
11. References
    1. Thompson and Ruttan (2021) Crit Dec Emerg Med 35(5):12-3
    2. Townsend (2001) Sabiston Surgery, Saunders, p. 907-9
    3. Cullen (1994) Ann Surg 220:564-9 [PubMed]
    4. Kuru (2018) 110(11): 726-32 [PubMed]
    5. Rossi (1996) AJR 166:567-73 [PubMed]
    6. Yahchouchy (2001) J Am Coll Surg 192:658-62 [PubMed]