Pediatric Meckel Diverticulum 

Updated: Nov 19, 2020
Author: Simon S Rabinowitz, MD, PhD, FAAP; Chief Editor: Carmen Cuffari, MD 

Overview

Background

Meckel diverticulum, also known as Meckel's diverticulum, is the most common congenital abnormality of the small intestine; it is caused by an incomplete obliteration of the vitelline duct (ie, failure of the omphalomesenteric duct to close).[ref74} Although originally described by Fabricius Hildanus in 1598, it is named after Johann Friedrich Meckel, who established its embryonic origin in 1809.[1, 2]

Despite the availability of modern imaging techniques, making the diagnosis is challenging. Although Meckel diverticulum is usually asymptomatic, two types of complications can require clinical attention. One type involves ectopic mucosal tissue and most often leads to gastrointestinal bleeding in younger children. In the second type, an obstruction, inflammation or, rarely, perforation of the bowel is present.

Pathophysiology

As noted earlier, Meckel diverticulum is caused by the failure of the omphalomesenteric duct to completely obliterate (at 5-7 weeks' gestation), followed by one of various complications.

The yolk sac is the first element to be formed within the gestational sac. It is involved in maternal-fetal transfer of nutrients in early gestation during the critical period of organogenesis. Early in embryonic life, the fetal midgut receives its nutrition from the yolk sac via the omphalomesenteric/vitelline duct. The duct then undergoes progressive narrowing and usually disappears by 7 weeks' gestation. When the duct fails to fully obliterate, different types of vitelline duct anomalies appear. Examples of such anomalies include (1) a persistent vitelline duct (appearing as a draining fistula at the umbilicus); (2) a fibrous band that connects the ileum to the inner surface of the umbilicus; (3) a patent vitelline sinus beneath the umbilicus; (4) an obliterated bowel portion; (5) a vitelline duct cyst; and, most commonly (97%) Meckel diverticulum, which is a blind-ending, true diverticulum that contains all of the layers normally found in the ileum.[3] The tip of the diverticulum is free in 75% of cases and is attached to the anterior abdominal wall or another structure in the remainder of cases.

Enterocystomas, umbilical sinuses, and omphaloileal fistulas are among the other congenital anomalies associated with Meckel diverticulum.

The diverticulum is usually supplied by the omphalomesenteric artery (a remnant of the vitelline artery), which arises from the ileal branch of the superior mesenteric artery. The artery typically terminates in the diverticulum; however, it has also been reported to continue up to the abdominal wall in some cases. Rarely, these blood vessels persist in the form of fibrous remnants that run between the Meckel diverticulum and the abdominal wall or small bowel mesentery.

A rare reported case of Meckel diverticulum was associated with other umbilical anomalies: A 4-year-old boy presented with abdominal pain, vomiting, and constipation.[4]  Upon surgical exploration, a band arising from a Meckel diverticulum was found, causing obstruction of the terminal ileum. A urachal cyst at the umbilicus was attached to the Meckel diverticulum at one end and to the urinary bladder on the other end through a patent urachus.

Although Meckel diverticulum almost always occurs on the antimesenteric border of the ileum, case reports have described a mesenteric location. As per the "rule of twos," it is usually 2 feet (40-60 cm) proximal to the ileocecal valve, 2 cm wide (and 2 inches [5 cm] long), found in 2% of the population,[5] often presents before age 2 years (or within the first 2 decades of lief), is twice as likely to be symptomatic in boys than girls, and contains ectopic mucosa about half the time (two types: gastric and pancreatic).[2] Meckel diverticulum is typically lined by ileal mucosa, but other tissue types are also found with varying frequency.

The heterotopic mucosa is most commonly gastric in origin. This is important because peptic ulceration of this or adjacent mucosa can lead to painless bleeding, perforation, or both. In one study, heterotropic gastric mucosa was found in 62% of cases, pancreatic tissue was found in 6%, both pancreatic tissue and gastric mucosa were found in 5%, jejunal mucosa was found in 2%, Brunner tissue was found in 2% and both gastric and duodenal mucosa were found in 2%.[3] Rarely, colonic, rectal, endometrial, and hepatobiliary tissues have been noted.

Epidemiology

United States data

The prevalence of Meckel diverticulum is usually noted to be approximately 2% of the population,[2, 5] but published series report a range from 0.2% to 4%.[6] Complications are only seen in about 5% of those with the anomaly. In a retrospective survey of 43 children's hospitals in the United States, 815 children had a Meckel diverticulectomy during a 2-year span.[7] Slightly more than half (60%) were symptomatic, and the remainder were incidental findings in children who had laparotomy for a different reason.

International data

Europe and Asia have reported prevalence figures similar to those found in the United States.

Race-related demographics

A study reviewed the Pediatric Hospital Information System (PHIS) database—which included patients admitted to 44 US children’s hospitals—over a 9-year period (2004-2012) to identify demographics of patients with International Classification of Diseases, Ninth Edition, (ICD-9) diagnoses of Meckel diverticulum and a procedure code for Meckel diverticulectomy. It analyzed data for age, payer, ethnicity, and symptoms and found the ethnic distribution of symptomatic Meckel diverticulum was 63.4% White, 4.7% Black, 16.4% Hispanic, 3.9% Asian, and 11.6% other.[8]

Sex-related demographics

Although no sex-based difference has been reported in studies that evaluated this condition as an incidental finding during operations or autopsies, males are as much as 3-4 times more prone to complications than females. In a large series of cases from 2007 to 2008, Meckel diverticulectomy was 2.3 times more common in boys, and boys accounted for 74% of the primary cases.[7]

Age-related demographics

The classic presentation of Meckel diverticulum in children is considered to be painless rectal bleeding in a toddler younger than 2 years. One large case series found that 53% of affected children had surgery before their fourth birthday. However, the largest group (slightly more than 30%) were younger than 1 year.[7] Although most other pediatric cases occur in patients aged 2-8 years, many continue to present with hematochezia.

Younger children have been reported to usually present with hematochezia, whereas adults present with obstruction. However, the series of 815 pediatric (< 8 y) cases described above found that a primary diverticulectomy was performed more commonly (30%) for obstruction than bleeding (27%), and that a substantial proportion (19%) of these patients had intussusception.[7] About one quarter did not have a clear cut diagnosis.

A 2019 study revealed that in 83 children with defined anatomic lead points resulting in intussusception, the most common etiologies in children younger than 2 years were Meckel diverticulum, duplication cyst, and benign polyps.[9]  Meckel diverticulum and intestinal duplication accounted for 81% (38/47) of these cases. The most common causes of secondary intussusception in children older than 2 years were intestinal polyps, including Peutz-Jeghers syndrome and Meckel diverticulum, accounting for 72% (26/36) of the cases.[9]

An earlier literature review of Meckel diverticulum in the neonatal period found that the most common manifestations in this age were bowel obstruction (58.3%) and pneumoperitoneum (33.3%).[10] In addition, in both term and preterm neonates, males were even more frequently affected than females, with a male-to-female ratio of 6.5:1.[10] Other neonatal presentations include perforation, intussusception, segmental ileal dilation, ileal volvulus, and massive hematochezia.[7]

In adults with Meckel diverticulum, obstruction and inflammation are more common presentations than lower gastrointestinal bleeding. Several population-based studies have reported a lower incidence of complications with increasing age, although other studies have not. Therefore, the issue of incidental diverticulectomy in older patients remains controversial.

Prognosis

Morbidity and mortality

The diagnosis of Meckel diverticulum can be quite elusive; therefore, a high index of suspicion is warranted to correctly and expeditiously diagnose this condition. Complicated Meckel diverticulum can lead to significant morbidity and mortality, most often because of a delay in diagnosis. For example, a higher frequency of intestinal infarction has been encountered in patients who present with complete intestinal obstruction. Causes of mortality include strangulation, perforation, and exsanguination because of delay in resuscitation.

Complications of Meckel diverticulum typically fall into the categories of bleeding, obstruction, or inflammation (diverticulitis), which could be related to foreign bodies and or tumors. Once a complication arises and surgery is required, the operative mortality and morbidity rates have both been estimated at 12%.[11] The cumulative long-term risk of postoperative complications in this cohort was found to be 7%. If the Meckel diverticulum is removed as an incidental finding, the risk of mortality and morbidity and long-term complications are much lower (1%, 2%, and 2%, respectively).[11]

Pandove et al described a case of internal herniation and intestinal obstruction due to Meckel diverticulum.[12]  This rare presentation resulted from internal herniation of bowel loops into a sac formed by mesentery of Meckel diverticulum and its adhesion band.

As many as 5% of complicated Meckel diverticulum contain malignant tissue.

Neuroendocrine tumors arising from Meckel diverticulum are very rare. A 2015 case report described Cushing syndrome due to ectopic adrenocorticotropic hormone (ACTH) secretion from a Meckel diverticulum.[13]  Use of somatostatin analogue scintigraphy allowed localization of the ectopic ACTH tumor source. Pathological analysis of the resected submucosal tumor of Meckel diverticulum confirmed a neuroendocrine tumor with immunohistochemistry that was positive for ACTH. Surgical resection led to complete resolution of symptoms.[13]

 

Presentation

History

Most patients with Meckel diverticulum live their entire lives without any symptoms. This condition is most frequently diagnosed as an incidental finding when a barium study or laparotomy is performed for other abdominal conditions.[3]

Symptomatic Meckel diverticulum is virtually synonymous with a complication. This is estimated to occur in as many as 4-16% of patients. Complications are the result of obstruction, ectopic tissue, or inflammation. In a study of 830 patients of all ages, complications included bowel obstruction (35%), hemorrhage (32%), diverticulitis (22%), umbilical fistula (10%), and other umbilical lesions (1%).

In children, most series have historically noted that hematochezia is the most common presenting sign.[14] Bleeding in adults is much less common.[15, 16]

In another study of 65 pediatric patients over a 12-year period, isolated gangrene of the Meckel diverticulum was reported in 10 cases with obstruction.[17]

Hemorrhage

Acute lower gastrointestinal (GI) bleeding is secondary to hemorrhage from peptic ulceration. Such ulceration occurs when acid secreted by heterotopic gastric mucosa damages contiguous vulnerable tissue, oftentimes resulting in direct erosion of a vessel. Clinically, hemorrhage is usually noted to be substantial painless rectal bleeding. However, some patients may present with pain preceding the onset of hematochezia. The pain can be quite significant and often delays the correct diagnosis.

Hematochezia

Most often, painless rectal bleeding (hematochezia) occurs suddenly and tends to be massive in younger patients.[18]  Bleeding occurs without prior warning and usually spontaneously subsides. The color of the stool often provides clinicians with a clue to determine the site of bleeding. This has been well addressed in a classic description of the types of rectal bleeding associated with Meckel diverticulum.[19]

The prevalence of different types of bleeding has been described as follows:

  • Dark red (maroon): 40%

  • Bright red: 35%

  • Bright red or dark red: 12%

  • Dark red or tarry: 6%

  • Tarry: 7%

When bleeding is rapid, stools are bright red or have an appearance like currant jelly. When slow bleeding occurs, the stools are black and tarry.

Obstruction

Abdominal pain may be reported when the presentation is related to an obstruction or inflammation. Relatively recent reports have brought into question the belief that intestinal obstruction in pediatrics secondary to Meckel diverticulum is not very prevalent, with some series reporting a prevalence of 25-40% of pediatric complications. Obstruction is the most common complication in adults. In children or adults, obstruction can be secondary to various mechanisms.[3]  Mechanisms include the following (none of these have clinical features that are pathognomonic, and the precise etiology is rarely known preoperatively):

  • Omphalomesenteric band (most frequent cause)

  • Internal hernia through vitelline duct remnants

  • Volvulus occurring around vitelline duct remnants

  • T-shaped prolapse of both efferent and afferent loops of intestine through a persistent vitelline duct fistula at the umbilicus in a neonate

  • Intussusception (when Meckel diverticulum itself acts as a lead point for an ileocolic or ileoileal intussusception)

Like other diverticula in the body, Meckel diverticulum can become inflamed. Diverticulitis is usually seen in older patients but has also been observed in children. Meckel diverticulum is less prone to inflammation than the appendix, because most diverticula have a wide mouth, have very little lymphoid tissue, and are self-emptying. The clinical presentation includes abdominal pain in the periumbilical area that radiates to the right lower quadrant. Persistence of periumbilical pain or a history of bleeding per rectum may be helpful in distinguishing this entity from appendicitis.

Unusual presentations

Unusual presentations of Meckel diverticulum have also been reported. A rare cause of abdominal pain was inversion without intussusception.[20]  Another case report described a perforation as a result of blunt abdominal trauma.[21] This report emphasized the importance of including perforation of Meckel diverticulum in the differential diagnosis of abdominal trauma.[21]  Another case report described a rare presentation of pyogenic liver abscess due to an infected Meckel diverticulum. Perforated Meckel diverticulum can rarely present as an abdominal abscess or as a pyogenic liver abscess. The authors conclude that that elective resection of a Meckel diverticulum should be considered in the presence of a pyogenic liver abscess if no other etiologies are identified,[22] but others include sarcoma,[23]  carcinoid tumor,[24] adenocarcinomas, and Burkitt lymphoma, as well as additional rare lesions.[21]

Foreign bodies

Foreign bodies can become confined in Meckel diverticulum and lead to obstruction or perforation. The most common foreign body that causes perforation in Meckel diverticulum is ingested bone fragments (58%), followed by wood splinters (14%), food (12%), pin/needles (9%), and miscellaneous (7%).[25]  One case report emphasized how chronic right lower quadrant abdominal pain could be related to a Meckel diverticulum: After years of intermittent nonspecific abdominal symptoms, an adolescent presented with signs of small bowel obstruction and was found to have a large enterolith in an inflamed Meckel diverticulum.[26] In a case report by Hussein et al, a phytobezoar caused obstruction of a Meckel diverticulum in a patient on high vegetarian diet.[27] The authors suggested that the intestinal dysmotility and poor coordination of the peristaltic waves at the site of the Meckel diverticulum could produce decreased ileal motility and slow intraluminal flow with impaction of foreign objects and stickiness of boluses of food.[27]

Ingestion of multiple foreign bodies is more commonly seen in individuals with psychiatric illness or intellectual disabilities. One case study described a child with autism spectrum disorder who presented to the emergency department with complaints of acute onset of abdominal pain and bilious vomiting.[28] Abdominal radiographs revealed evidence for obstruction with dilated small bowel with air-fluid levels. A computed tomography scan revealed foreign objects in the distal small bowel, with dilatation of the proximal intestine and decompressed bowel distally. During exploratory laparotomy, a Meckel diverticulum was found containing multiple foreign objects.[28]

Physical Examination

Most patients with Meckel diverticulum are asymptomatic. However, patients can present with various clinical signs, including peritonitis or hypovolemic shock. The three most common symptomatic presentations are gastrointestinal (GI) bleeding, intestinal obstruction, and acute inflammation of the diverticulum.

When a severe bleeding episode occurs, the patient can present in hemorrhagic shock. Tachycardia is an early clinical sign of hemorrhagic shock, but pale conjunctivae and orthostatic hypotension may actually precede this.

Most patients with intestinal obstruction present with abdominal pain, bilious vomiting, generalized abdominal tenderness, distention, hypoactive or hyperactive bowel sounds, peritoneal signs, and rebound tenderness upon examination. Patients may develop a palpable abdominal mass. Occasionally, when patients do not present early or if the diagnosis is missed, the obstruction can progress to intestinal ischemia or infarction; the latter manifests with acute peritoneal signs and lower GI bleeding.

Patients with diverticulitis present with either focal or diffuse abdominal tenderness. Usually, abdominal tenderness is more marked in the periumbilical region than that from the pain of appendicitis. Children may present with abdominal guarding and rebound tenderness, in addition to abdominal tenderness. Abdominal distention and hypoactive bowel sounds are late findings. Suppurative Meckel diverticulum can present in a child with abdominal pain and periumbilical cellulitis.[29]  Rarely, Meckel diverticulum has been reported to become incarcerated (Littre hernia) in the inguinal,[30]  femoral, or obturator hernial sacs or even incisional defects.

 

DDx

 

Workup

Approach Considerations

The history and physical examination are of paramount importance for establishing a clinical diagnosis of Meckel diverticulum. Perform a rapid assessment of any child with significant bleeding or signs of small bowel obstruction, ischemia, or inflammation. Meckel diverticulum is a relatively uncommon etiology for any of these complications, but it must always be considered in the differential diagnosis.

Laboratory Studies

Routine laboratory findings, including a complete blood cell (CBC) count, electrolyte levels, glucose, blood urea nitrogen (BUN), creatinine levels, and coagulation screen results, are not helpful in establishing the diagnosis of Meckel diverticulum, but they are necessary to manage a patient with gastrointestinal bleeding along with a blood type and cross-match.

Hemoglobin and hematocrit levels are low in the setting of anemia or significant bleeding. In one series, 58% of children had average hemoglobin levels lower than 8.8 g/dL.

In a prospective linear observational study of 73 children with a diagnosis of symptomatic Meckel diverticulum that compared mean hemoglobin level before onset of symptoms and at presentation of rectal bleeding, there was a 58% correlation between Meckel diverticulum and hematochezia with a drop in hemoglobin of more than 2 g/dL.[31]

Ongoing bleeding from a Meckel diverticulum can cause iron deficiency anemia. However, megaloblastic anemia can also be seen due to vitamin B12 or folate deficiency. These can occur secondary to small bowel overgrowth if chronic dilatation and/or stasis related to the diverticulum is present. Low albumin and low ferritin levels may erroneously lead to a diagnosis of inflammatory bowel disease.

Imaging Studies

According to the Mayo Clinic, "Meckel's diverticulum is frequently suspected, often looked for, and seldom found."[32] Preoperative diagnosis is difficult, especially if the presenting symptom is not gastrointestinal (GI) bleeding. In one series, patients often had a correct preoperative diagnosis if the presenting symptom was GI bleeding, but only 11% of preoperative diagnoses were correct if other symptoms predominated.[32]

Imaging studies are performed to confirm a clinical suspicion of Meckel diverticulum.

Radiography

Plain radiography of the abdomen is of limited value. It may reveal evidence of nonbleeding complications, including enteroliths and signs of intestinal obstruction, such as air or air-fluid levels (see the image below), or perforation.

Pediatric Meckel Diverticulum. Anteroposterior vie Pediatric Meckel Diverticulum. Anteroposterior view of an abdominal radiograph showing multiple dilated loops of a small bowel with air-fluid levels.

Barium studies have largely been replaced by other imaging techniques; however, if a barium study is indicated, it should never precede the technetium-99m scan (99m-Tc pertechnetate scintigraphy; Meckel scan) (see below), because barium may obscure the hot spot.

Traditional small-bowel series using barium have been unreliable in the detection of Meckel diverticulum. However, for patients who require a barium study to primarily look for other conditions, enteroclysis is more sensitive in detecting Meckel diverticulum. Enteroclysis involves using a continuous infusion of barium with adequate compression of the ileal loops and intermittent fluoroscopy to detect Meckel diverticulum. If the barium mixture is too dense and the fold pattern cannot be visualized, carboxymethylcellulose sodium can be used as the contrast medium.

On barium studies, Meckel diverticulum may appear as a blind-ending pouch on the antimesenteric side of the distal ileum. If filling defects are visualized, the diverticulum may contain a tumor. Characteristic radiologic signs for Meckel diverticulum include demonstration of a triradiate fold pattern or a mucosal triangular plateau. Occasionally, a gastric rugal pattern may also be found within the Meckel diverticulum.

A barium enema can be performed if intussusception is suspected. Some people have tried hydrostatic therapy to reduce intussusception, but this has not been found to be useful.

Meckel scan

When a patient has GI bleeding suggestive of Meckel diverticulum, the diagnostic evaluation should focus on the "Meckel scan," a 99m-Tc pertechnetate scintiscan (0.25 mCi/kg in children, up to the dosage used in adults; 8-12 mCi in adults).[2] The Meckel scan is the preferred modality, because it is noninvasive, involves less radiation exposure, and is more accurate than an upper GI and small-bowel follow-through study. The pertechnetate is taken up by heterotopic gastric mucosa. Because bleeding from the Meckel diverticulum is related to acid-induced damage of mucosa adjacent to the parietal cell containing tissue, it is always included early in the work-up.[33]

After intravenous injection of the isotope, a gamma camera is used to scan the abdomen. This procedure usually lasts approximately 30 minutes.[2] Gastric mucosa secretes the radioactive isotope; thus, if the diverticulum contains this ectopic tissue, it is recognized as a hot spot.

Based on a retrospective review of Meckel scans performed from 1993-2011, the Meckel scan has a reported sensitivity of 94% and a specificity of 97% in children.[34] In adults, in whom GI bleeding is a much less common presentation, the scan has a lower sensitivity (62.5%), a much lower specificity (9%), and a lower accuracy (46%).[35]

Because the Meckel scan is specific for gastric mucosa (ie, in the stomach or ectopic) and not specifically diagnostic of Meckel diverticulum, false-positive results occur whenever ectopic gastric mucosa is present. Duodenal ulcer, small intestinal obstruction, some intestinal duplications, ureteric obstruction, aneurysm, and angiomas of the small intestine have yielded positive results. False-negative results can occur when gastric mucosa is very slight or absent in the diverticulum, if necrosis of the diverticulum has occurred, or if the Meckel diverticulum is superimposed on the bladder.[36]

Accuracy of the scan may be enhanced with administration of cimetidine, glucagon, and pentagastrin. Cimetidine enhances the uptake and blocks the secretion of 99m-Tc pertechnetate from ectopic gastric mucosa,[37]  which helps to improve the lesion-to-background ratio in enhancing a Meckel scan. Pentagastrin also enhances uptake of the isotope but also increases peristalsis, attenuating its value. Glucagon is used to decrease peristalsis, thus allowing the signal to be taken up during a longer exposure time. One strategy uses both pentagastrin and glucagon. With newer imaging technology, false-positive and false-negative rates have declined.

Bleeding scan

A bleeding scan can be performed to identify the source if the patient is bleeding at 0.1 mL/min or more. The scan involves removing and labeling some of the patient's own red blood cells 99m-Tc, reinjecting them into the patient, and then scanning the abdomen for hot spots.[38, 39]

A retrospective study demonstrated that a repeat Meckel scan can be diagnostic in patients with an equivocal or negative finding who continue to have bleeding and a high clinical suspicion for Meckel diverticulum.[40] Following an equivocal scan, 58% of the repeat scans were found to be positive, and 85% of these had a Meckel diverticulum. For patients with a negative first scan with a persistent high suspicion for Meckel diverticulum, 14% were positive on repeat study, and 86% remained negative. A repeat scan can also be helpful to differentiate a false-positive result from a true Meckel diverticulum.[40]

Arteriography

Selective arteriography may be helpful in patients in whom the results from scintigraphy and barium studies are negative. Usually, this occurs if the bleeding is either intermittent or has completely resolved.

When the rate of bleeding is greater than 1 mL/min, a superior mesenteric arteriogram can be helpful, but interpretation may be difficult due to overlying blood vessels. In these cases, selective catheterization of the distal ileal arteries may be needed.

Demonstration of abnormal arterial branches, dense capillary staining, or extravasation of the contrast medium confirms the presence of a Meckel diverticulum. However, a well-developed arterial supply may not always be present in the Meckel diverticulum; thus, these arteriographic signs are not very reliable.

Computed tomography (CT) scanning

Previously, abdominal CT scanning was not considered helpful, because differentiating Meckel diverticulum from the small-bowel loops is difficult. However, a blind-ending, fluid-filled, and/or gas-filled structure in continuity with small bowel may be visualized. CT scanning may also reveal an enterolith, intussusception, or diverticulitis. CT enterography advancements have increased the sensitivity in the diagnosis of Meckel diverticulum.[33]

In a retrospective study to determine the frequency of detecting symptomatic and asymptomatic Meckel diverticulum in patients known to have the lesion, comprising a total of 85 CT examinations (23 on 14 symptomatic patients and 62 on 26 asymptomatic patients) after surgical resection of Meckel diverticulum, a Meckel diverticulum was detected in 34.1% of patients.[41] In symptomatic patients, Meckel diverticulum could be seen in 57.1% of patients on at least one CT examination and in 56.5% of the total CT examinations. Among the 14 symptomatic patients with negative studies, 6 involved children with little peritoneal fat, which likely related to the failure to see the diverticulum. In asymptomatic patients, Meckel diverticulum was detected in 42.3% patients on at least one CT examination and 25.8% of the total CT examinations. The authors concluded that CT scanning was able to detect Meckel diverticulum in 47.5% of all patients. The highest rates of success were found in symptomatic patients and in those with adequate peritoneal fat.[41]

Ultrasonography

Ultrasonography has been used in some cases of Meckel diverticulum. This modality tends to be helpful if the patient presents with anatomic rather than mucosal complications. A retrospective study that analyzed ultrasound characteristics of pathologically proven Meckel diverticulum concluded that this condition is difficult to detect by ultrasound (detection rate of 15.5%).[42] However, the presence of complications such as intussusception (24%), intestinal obstruction (24%), and diverticulitis (15.5%) increased the rate of detection.

Capsule endoscopy

Capsule endoscopy is a relatively new technology that assists with imaging in the small intestine . Wireless capsule endoscopy has been successfully used to identify Meckel diverticulum in young children and adolescents[43, 44]  especially after endoscopy and colonoscopy failed to detect the site of bleeding. Features that are noted include two lumina, a thickened bridge, an ulcer and, occasionally, direct visualization of ectopic gastric mucosa. However, during active bleeding, the diverticulum itself may be missed, lowering its sensitivity in those circumstances. In adults, this same technique has been used to identify an inverted Meckel diverticulum that presented as GI bleeding.[45]

Other imaging studies

Magnetic resonance imaging (MRI)

Newer imaging modalities have been used to diagnose Meckel diverticulum. Magnetic resonance (MR) enterography (MRE) was able to visualize a Meckel diverticulum in an adult who presented with GI bleeding after numerous other modalities had failed to reveal the source of bleeding. MRI of another case revealed a cystlike structure of the small intestine in the iliac fossa with high signal intensity.[46] This cystlike structure had a tear drop shape in the nonenhanced T1-weighted spin-echo coronal image, suggesting that it was a blood-filled body.

MR imaging can also be used to detect inflamed Meckel diverticulum, which is especially attractive for pediatric patients due to the lack of ionizing radiation.[46]

Multidetector-row CT (MDCT) scanning

In a retrospective study that used MDCT scanning evaluate a series of patients prior to surgery for small bowel obstruction for factors such visualization of Meckel diverticulum, complication type of Meckel diverticulum, location and grade of small bowel obstruction, and the identification of a normal appendix, the authors found that when the Meckel diverticulum was visualized on preoperative MDCT scanning, it could be considered the likely source of the obstruction.[47] If the obstructive process was seen in the midline location, at the terminal branch of the superior mesenteric artery, then the Meckel diverticulum was possibly the cause of the obstruction. However, the preoperative diagnosis of Meckel could not be made if it was not noted in MDCT scanning; this is frequently the situation in children as the diverticulum is not as developed. Two children with obstruction, were noted to have congenital bands between the mesentery and Meckel diverticulum.[47]

Single-photon emission tomography/CT (SPECT/CT) scanning

Ambiguous results of a Meckel scan have recently been clarified with hybrid SPECT/CT scanning. SPECT/CT scanning enhances the sensitivity of a Meckel scan by precisely localizing ectopic gastric mucosa at an abnormal anatomic structure, while decreasing the false-negative or false-positive results associated with a traditional Meckel scan. Because of increased radiation, its greatest value may be in complicated situations.

In a case report that employed SPECT/CT fusion imaging after a CT scan showed an irregular inflammatory lesion believed to be an abscess in the distal ileum with a normal appendix, 99m-Tc pertechnetate scintigraphy was performed after the intravenous injection of 370 MBq 99m-Tc pertechnetate.[48]  Dynamic (2 min/frame) and delayed (30 min, 60 min) images revealed the focal concentration to be under the liver, similar to the gastric uptake. SPECT/CT fusion imaging clarified that the focal concentration was in the distal ileum, surrounded by the inflammatory lesion.[48] Thus, in the face of complications related to a Meckel diverticulum, SPECT/CT fusion imaging can enhance the preoperative findings. 

A 3-year-old girl was diagnosed with Meckel diverticulum by planar scintigraphy; due to resolution of her symptoms and concomitant congenital heart disease, surgery was not performed at the time.[49] She presented 7 years later with massive hematochezia; a repeat planar scintigraphy showed an uptake in the area of the kidney. Whether this was due to physiologic uptake by the kidney or by ectopic gastric mucosa is unclear. A SPECT/CT scan was able to confirm that the Meckel diverticulum was the exact anatomic site of the focal concentration.[49]

Histologic Findings

The surgical and oncologic relevance of Meckel diverticulum comes from its pluripotent cell lining. In one study, heterotropic gastric mucosa was found in 62% of cases, pancreatic tissue was found in 6%, both pancreatic tissue and gastric mucosa were found in 5%, jejunal mucosa was found in 2%, Brunner tissue was found in 2%, and both gastric and duodenal mucosa were found in 2%.[3]

Rarely, ectopic tissue may undergo malignant degeneration; consequently, because the wall of the diverticulum is thin, a small cancer can penetrate and widely metastasize within the peritoneal space. In a case report, the immunohistochemical profile of the tumor cells, along with the presence of gastric epithelial differentiation, favored its origin in ectopic gastric epithelium.[50]  Per the authors’ report at the time, this was the first patient with gastric cancer peritoneal metastases reported in the literature and successfully treated.

GISTs can coexist along with other tumors. Carcinoid, pancreatic, and gastrointestinal stromal tumors (GIST) have been found in resected specimen of perforated or symptomatic Meckel diverticulum. A case report described a case of perforated Meckel diverticulum in which histologic findings revealed a GIST within the Meckel diverticulum.[51] The study concluded that segmental resection of the small bowel should be considered in cases of perforation due to the risks of a tumor within the diverticulum.

Helicobacter pylori is a gram-negative rod that has virulence factors, allowing them to survive in the mucus layer adherent to gastric epithelium. The presence of H pylori in a heterotopic gastric mucosa in a Meckel diverticulum has not been widely reported, and its actual prevalence may vary. In a review of the literature for both adult and pediatric cases, a 2% prevalence of H pylori was noted in heterotopic gastric mucosa.[52] The authors thus proposed considering an addition to the “rule of twos” related to Meckel diverticulum. In contrast, a small series of 21 consecutive patients from Turkey using polymerase chain reaction (PCR) failed to identify 23S ribosomal RNA sequences from the organism in their 12 surgical specimens with heterotopic gastric mucosa.[53]

Although the underlying mechanisms leading to the rarely described perforated Meckel diverticulum in neonates have not been fully elucidated, it is thought that ectopic mucosa appeared to have little association with the development of perforation in these patients. Previous studies suggested that bowel obstruction was the most common etiology resulting in perforated Meckel diverticulum in term infants. High pressure within a thin diverticulum was hypothesized to play a vital role in the development of perforation in the neonatal period.[54, 55]  However, a small case series describing five neonates with perforation in a Meckel diverticulum demonstrated extensive inflammation without ectopic mucosa and gangrenous inflammation.[56] The authors of the series proposed that hypoxia, inadequate blood supply, intestinal permeability, and early use of postnatal steroid and indomethacin can increase the risk of spontaneous intestinal perforation.[56]

Like the authors of the small series above who inferred that the perforation may be related to intestinal immaturity, the authors of this article agree that in premature infants and neonates, conditions could lead to a necrotizing enterocolitis event that is centered in the Meckel diverticulum in a vulnerable patient. Another small case series that described seven cases of neonatal perforated Meckel diverticulum found heterotopic mucosa in just two cases and no evidence of intrinsic bowel wall weakness.[57]

In another case report, an inverted Meckel diverticulum contained several aberrant smooth muscle bundles.[58]  The investigators proposed that these muscle bundles may have produced abnormal peristaltic movement, acting as a lead point for the inversion and ileoileal intussusception.

A retrospective case study showed Meckel diverticulum with gastric heterotopia has an increased frequency of abdominal pain, vomiting/nausea, and rectal bleeding compared with Meckel diverticulum with pancreatic heterotopia or no heterotophic tissue.[59]

 

Treatment

Medical Care

Although numerous retrospective studies have described trends in the diagnosis and treatment of Meckel diverticulum, the amount of cases has been insufficient to warrant official guidelines.

The emergency department evaluation and treatment of patients depends on the clinical presentation of Meckel diverticulum.

Because most symptomatic patients are acutely ill, establish an intravenous line immediately, start crystalloid fluids, and keep the patient on nothing by mouth (NPO) status. Obtain the blood investigations suggested earlier with a type and cross-match (see Workup, Laboratory Studies). If significant bleeding occurs, perform a transfusion of packed red blood cells.

A patient who presents with intestinal obstruction usually requires nasogastric (NG) decompression. After passing the NG tube, obtain plain radiography of the abdomen.

When a child presents with bleeding, specifically a dark tarry stool, perform a gastric lavage to rule out upper gastrointestinal bleeding. If the gastric lavage is negative for bleeding, consider performing an upper endoscopy and flexible sigmoidoscopy.

Meckel scan results may be negative despite a high clinical suspicion of Meckel diverticulum. Consult the surgery team to discuss the possible need for laparoscopy and/or laparotomy, even without a nuclear medicine diagnosis.

Consultations

Consultations with the following specialists may be appropriate:

  • Radiologist

  • Surgeon

  • Gastroenterologist

Surgical Care

If the patient is bleeding but is hemodynamically stable, a Meckel scan is warranted. Alternatively, the presence of peritoneal signs or hemodynamic instability demands urgent surgical intervention. Signs of small bowel obstruction also require surgical intervention.[60]

A stationary foreign body within the right lower quadrant on imaging proximal to the ileocecal valve should raise suspicion for a Meckel diverticulum and prompt early surgical intervention. In a case report, a 6-year-old boy presented after having ingested a coin 2 days prior; serial abdominal radiographs demonstrated persistence of the coin in the right lower quadrant without a change in position over a 72-hour interval.[61]  The coin led to both obstruction and perforation of a Meckel diverticulum.

Meckel diverticula containing gastric heterotopia predispose to local hyperacidity, mucosal ulceration, and gastrointestinal (GI) bleeding in children. Eradication of acid-producing oxyntic cells is always performed by segmental diverticulectomy, with or without segmental enterectomy. Definitive treatment of a complication, such as bleeding, is excision of the diverticulum along with the adjacent ileal segment. Excision is achieved by performing a wedge resection of the adjacent ileum and anastomosis with the use of a stapling device.[62] Adjacent ileum is included in the resection because ulcers frequently develop in the adjacent bowel and may continue to bleed. In those rare instances when the diverticulum is located on the mesenteric border, resection and anastomosis is preferred instead of a wedge resection.

Because of concern that ulcers in the adjacent bowel may continue to bleed if only the diverticulum is removed, a group compared whether a simple diverticulectomy rather than a segmental bowel resection is adequate treatment for GI bleeding secondary to Meckel diverticulum.[63]  The primary outcome was postoperative bleeding during the initial hospitalization, whereas secondary outcomes included postdischarge bleeding, transfusion or additional procedure requirement, readmission, and overall complications. The study concluded that simple diverticulectomy is adequate for the treatment of GI bleeding caused by Meckel diverticulum. Furthermore, diverticulectomy appears to have a lower overall complication rate.[63]

In support of this finding, a retrospective review of all surgical resections of a bleeding Meckel diverticulum at a tertiary-referral children's hospital found that a diverticulectomy-only procedure completely eradicates gastric heterotopia without an increased risk of continued bleeding or complications and significantly shortens hospitalization.[64] Ultimately, real-time intraoperative findings by the surgeon should dictate how to proceed; although the pursuit of a less invasive procedure is desired, one should be careful not to treat a patient too conservatively and ultimately result in greater complications for the patient.

Laparoscopy

Successful resection of a Meckel diverticulum, even in children and infants, can also be accomplished through laparoscopy, using an endoscopically designed autostapling device.[65, 66, 67] A large series of national trends in the surgical management of Meckel diverticulum found that one fourth of cases are now treated laparoscopically.[7] This group was older (6.4 y ± 5.1 y vs 5.1 y ± 5.3 y), had shorter length of stay, and trended toward lower total hospital charges.

Minimally invasive surgery via laparoscopy in patients with Meckel diverticulum has been associated with faster recovery time without increasing complications, offering a safe alternative to open surgery.[68]

In some cases of Meckel diverticulum, a primitive persistent right vitelline artery originating from the mesentery has been found during operation. When present, the artery is noted to supply the Meckel diverticulum; therefore, it must be identified and ligated during the operation.

Diagnostic laparoscopy is now being used more commonly in cases where Meckel diverticulum is the cause of intestinal perforation, which is a less common presentation in young children. A case report described the use of laparoscopy in a neonate with pneumoperitoneum to diagnose and surgically resect the perforated Meckel diverticulum.[69]  Using a multiuse single-site port in the umbilicus potentially reduces the preoperative and postoperative phases, allowing for earlier resumption of enteral nutrition, which is beneficial outcome in newborns.

Enteroscopy

Double-balloon enteroscopy (DBE) is a relatively new technique used to diagnose a bleeding Meckel diverticulum and to assist in a minimally invasive standard surgical resection. Previously, DBE has been used as a diagnostic tool followed by laparoscopic treatment of Meckel diverticulum. 

In a retrospective study (2011-2014) of 21 pediatric patients with melena and or/maroon-colored stools who underwent retrograde transanal DBE, 14 children had Meckel diverticulum that were all successfully treated with standard resection through an umbilical incision with exteroscopic light guidance, 5 children had a negative DBE study, and 2 had a lesion that prevented insertion of the enteroscope.[70] A clear advantage of this technique is that direct visualization of the distal small bowel lumen permits easy identification of the bleeding source. Noninvasive diagnostic methods such as ultrasonography, scintigraphy, and computed tomography (CT) scanning often yield false-positive or false-negative results, which may delay laparoscopy and treatment in pediatric patients. Note that a potential significant limitation of DBE is that the upper small bowel is not examined. Thus, DBE should not be routinely used as the first investigation to diagnose GI bleeding in patients presenting with a large quantity of melena and/or maroon-colored stools.[70]

Conversely, a case report described how retrograde DBE was employed to reduce an intussusception with an inverted Meckel diverticulum as the lead point.[71] Pressure was successfully applied to the protruding lesion using a contrast medium injection after wedging the lumen with a balloon to prevent distal flow, relieving the obstruction. By reducing the intussusception, emergent surgery was avoided. Endoscopic tattooing enabled elective laparoscopy-assisted surgery with minimum laparotomy to resect the inverted Meckel diverticulum.[71] In those with advanced endoscopic techniques along with a multidisciplinary surgical team, retrograde DBE can be useful for the investigation and treatment of ileal intussusception. It is important to note that this method does not necessarily entirely eliminate the need for surgery, and further studies are required before its benefit is fully established.

Mizutani et al determined the specific characteristics of hemorrhagic Meckel diverticulum and incidental Meckel diverticulum at DBE.[72] Findings during the procedure were classified into either major (ectopic gastric mucosa and/or open ulcer) or minor (ringlike scar). Hemorrhagic Meckel diverticulum correlated more with these findings. Specificity of major findings was 100%, and specificity of major and/or minor findings was 96%. These results allowed identification of asymptomatic Meckel diverticulum, thus avoiding unnecessary laparotomy/laparoscopy and diverticulectomy.[72]

The most common postoperative complication after Meckel’s diverticulectomy is adhesive intestinal obstruction. This usually presents with GI bleeding, and has been most often reported in patients with an ischemic and congested intestine.[73]

Management of Meckel diverticulum in asymptomatic patients is controversial. In the past, if a Meckel diverticulum was encountered in a patient undergoing abdominal surgery for some other intra-abdominal condition, many surgeons recommended its removal. This practice was questioned when a large case series described an overall 4.2% likelihood of complications in Meckel diverticulum and a decreasing risk with increasing age.[74] The investigators concluded that, assuming a 6% mortality rate from Meckel diverticulum complications, 400 asymptomatic diverticula would have to be excised to save one patient.

Another faction favors prophylactic removal of a diverticulum, which is a simple operation. This view is supported by data that demonstrate managing a complication of Meckel diverticulum is associated with high morbidity and mortality. Other authors feel the only exception to universal excision is if the diverticulum is so broad based or so short that stapled excision cannot be performed technically. Fortunately, patients are less likely to develop complications in both of these situations.

One small case series suggested that only patients younger than 50 years clearly benefited from removal if Meckel diverticulum was discovered unintentionally.[75]

Another study examined whether the appearance of the Meckel diverticulum was able to predict the need for resection based on the potential for complications.[76]  Using age, sex, clinical features, laboratory data, perioperative findings (diverticulum length, diameter, depth, thickening, height-to-diameter ratio [HDR]), pathology, and postoperative follow-up for evaluation, the authors found a correlation between the age of the patient and the size (length, diameter, and depth) of the Meckel diverticulum. With increasing age, Meckel diverticulum reaches larger sizes. The macroscopic appearance of the Meckel diverticulum did not predict the presence of heterotopic gastric mucosa and could not be used to guide subsequent surgery. Specifically, a thickened diverticulum had the same (68%) chance of containing heterotopic gastric mucosa as one without this finding (63%).[76] The study authors concluded that, regardless of appearance, Meckel diverticulum should be removed, except in certain situations unrelated to complications, such as peritonitis due to appendicitis or bowel perforation.

The limitations of this study were that it had a small sample size (50 children) and that macroscopic thickening is a subjective criterion, which differs among clinicians.[76] The study also found that resection of incidental Meckel diverticulum is not associated with higher operative morbidity or mortality than resection of symptomatic Meckel diverticulum, and thus all Meckel diverticulum should be removed.

 

Medication

Medication Summary

In addition to definitive therapy, urgently administer a regimen of antibiotics (eg, ampicillin, gentamicin, and clindamycin or cefotetan) whenever acute Meckel diverticulitis, strangulation, perforation, or signs of small bowel obstruction or sepsis are present.

Antibiotics

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the clinical setting.

Ampicillin (Omnipen, Marcillin)

Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms.

Clindamycin (Cleocin, Cleocin Pediatric, ClindaMax Vaginal)

Useful treatment for serious skin and soft tissue infections caused by most staphylococci strains. Also effective against entericaerobic and anaerobic flora, except enterococci. Inhibits bacterial protein synthesis by inhibiting peptide chain initiation at the bacterial ribosome, where it preferentially binds to the 50S ribosomal subunit, causing bacterial replication inhibition.

Gentamicin (Gentacidin, Garamycin)

If used in combination with an antianaerobic agent, such as clindamycin or metronidazole, provides broad gram-negative and anaerobic coverage. Dosing regimens are numerous and adjusted on the basis of creatinine clearance and changes in distribution volume.

Cefotetan (Cefotan)

Second-generation cephalosporin used as single-drug therapy to provide broad gram-negative coverage and anaerobic coverage. Half-life is 3.5 h. Inhibits bacterial cell wall synthesis by binding to ≥ 1 of the penicillin-binding proteins; inhibits final transpeptidation step of peptidoglycan synthesis, resulting in cell wall death.

Antibiotics have proven effective in decreasing rate of postoperative wound infection and improving outcome in patients with intraperitoneal infection and septicemia.