eMedicine Specialties > Radiology > Pediatrics

Meckel Diverticulum

Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP, Chairman of Medical Imaging, Professor of Radiology, NGHA, King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia
Muthusamy Chandramohan, MBBS, DMRD, FRCR, Consultant Radiologist, Bradford Teaching Hospitals, UK; Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute

Updated: May 6, 2008

Introduction

Background

Meckel diverticulum represents a true diverticulum of the ileum containing all 3 layers of the bowel wall. Meckel diverticulum develops if the omphalomesenteric or vitelline duct, which connects the primitive midgut with the yolk sac, fails to obliterate, which normally occurs at 7-8 weeks of gestation. Heterotopic tissue, including gastric mucosa and pancreatic tissue, is present in 50% of patients.

Symptoms resulting from a Meckel diverticulum occur because of complications and are more frequent in children than in adults and include hemorrhage and intestinal obstruction. Hemorrhage is usually due to erosion of adjacent ileal mucosa by acid produced by ectopic gastric mucosa. Intestinal obstruction is most often due to volvulus about the Meckel diverticulum or intussusception with the diverticulum as the lead point.¹

Meckel diverticulum is notoriously difficult to diagnose at both clinical and imaging examination because the symptoms and imaging features are nonspecific.^1,2,3,4,5

Related Medscape topics:
Specialty Site Radiology
Specialty Site Gastroenterology
Resource Center Diverticulosis

Pathophysiology

Ectopic gastric or pancreatic mucosa is found in 50% of patients with Meckel diverticula. Rarely, colonic or hepatobiliary tissue is found. Symptoms may develop because of ulceration within the gastric or adjacent ileal mucosa and gastrointestinal bleeding. Intestinal obstruction, perforation, and inflammation are further complications (see Mortality/Morbidity, below).^5,6

Single or multiple enteroliths may develop within the lumen of the diverticulum in as many as 10% of patients. Most enteroliths show a peripheral calcification. Obstruction of the lumen by an enterolith may lead to diverticulitis. Extrusion of an enterolith into the lumen of the small bowel may cause intestinal obstruction similar to a gallstone ileus. Herniation of a Meckel diverticulum into the inguinal canal is called a hernia of Littre.^1,7

Frequency

United States

Meckel diverticulum is found in 2-3% of individuals at autopsy, and it is the most common congenital anomaly of the gastrointestinal tract.

International

Worldwide, the frequency of Meckel diverticulum is the same as that in the United States.

Mortality/Morbidity

Complications resulting from a Meckel diverticulum occur in 20% of patients. Most patients present with unexplained lower gastrointestinal bleeding. In most of these patients (95%), ectopic gastric mucosa within the diverticulum causes the bleeding.³

The second most common complication is intestinal obstruction, which results either from intussusception of the diverticulum into the lumen of the small bowel (inverted diverticulum) or from a volvulus. A volvulus occurs around a fibrous band attaching the omphalomesenteric diverticulum to the umbilicus. The diverticulum may become inflamed as a result of obstruction by an enterolith. The diverticulum may become herniated into the inguinal canal and cause intestinal obstruction.^1,7

Rarely, benign and malignant tumors may both occur within a Meckel diverticulum and include polyps, carcinoid tumors, adenocarcinoma, and sarcoma.

The incidence of tumors reported with Meckel diverticulum is 0.5-3.2%. Occasionally, an ulcer in a patient with Meckel diverticulum becomes perforated, leading to peritonitis. The highest morbidity and mortality rates occur with volvulus.

Related eMedicine topics:
Gastrointestinal Bleeding, Lower
Gastrointestinal Bleeding, Upper
Lower Gastrointestinal Bleeding: Surgical Perspective
Upper Gastrointestinal Bleeding: Surgical Perspective

Race

No race predilection exists.

Sex

The male-to-female ratio is 3:1.

Age

Most patients with symptoms of Meckel diverticula present when they are younger than 10 years.^8,9

Anatomy

The primitive endodermal tube of the gut is divided into the foregut, which is supplied by the celiac axis; the midgut, which is supplied by the superior mesenteric artery; and the hindgut, which is supplied by the inferior mesenteric artery. Early in development, the rapid proliferation of the gut wall obliterates the lumen, which is followed by recanalization. The midgut enlarges rapidly during the first 5 weeks of gestation and becomes too large for the abdominal cavity; subsequently, it is herniated into the umbilical cord.

The apex of the herniated midgut is continuous with the vitellointestinal duct and the yolk sac, which, even at this early stage of development, is reduced to a fibrous strand. The axis of the herniated midgut is formed by the superior mesenteric artery, which subdivides the midgut into a cephalic and caudal limb. The cephalic limb eventually forms most of the upper small bowel, while the caudal limb forms the terminal 60 cm or so of the small bowel, cecum, and colon as far as the junction of the proximal two thirds and distal one third of the transverse colon.

At approximately the 10th week of gestation, the midgut begins its return into the abdominal cavity. This return occurs by a highly complex developmental process, and as a result, numerous anomalies of the bowel may ensue, which include bowel atresias and stenoses, abnormalities of the vitellointestinal duct, failure of cecal descent, malrotation, malfixation, reversed bowel rotation, and exomphalos.¹⁰

Meckel diverticulum is a remnant of the embryonic vitellointestinal duct, which is a communication between the primitive midgut and the yolk sac; thus, a Meckel diverticulum is always on the antimesenteric border. Occasionally, the diverticulum ends in a fibrous solid strand. The vitellointestinal duct may persist as a fistula or fibrous band connecting the small bowel to the umbilicus or as a cyst within a fibrous band passing from the antimesenteric border of the small bowel to the umbilicus (see Images 1-4).

Presentation

Patients may present with acute or chronic gastrointestinal bleeding. Some patients are evaluated primarily for anemia. Vague pain in the lower abdomen is not unusual and may be present for several years. Patients may present with an acute abdomen resulting from acute diverticulitis, intestinal obstruction, or perforation; however, most patients with Meckel diverticula are asymptomatic, and the diverticulum is found incidentally on imaging, surgery, or autopsy.

Preferred Examination

Plain radiography, barium studies, angiography, computed tomography (CT), ultrasonography, and scintigraphy all play complementary roles in the diagnosis of the complications of Meckel diverticulum. The diagnosis is notoriously difficult and remains a continuing challenge for the radiologist.^{1,4,5,8,9,10,11,12,13,14,15}

Limitations of Techniques

In all imaging modalities, findings of Meckel diverticulum are nonspecific. Most Meckel diverticula are diagnosed during surgery or autopsy, with imaging playing a secondary role. The most sensitive technique is scintigraphy, and various modifications to imaging techniques have been devised to improve sensitivity. Ultrasonography and CT are improving and can help in making an anatomic diagnosis.

Differential Diagnoses

Abdominal Aortic Aneurysm, Diagnosis	Intussusception, Child
Embolization, Hemorrhage	Small-Bowel Obstruction
Embolization, Vascular Lesions
Gastrointestinal Bleeding, Lower
Gastrointestinal Stromal Tumors - Leiomyoma/Leiomyosarcoma

Radiography

Findings

Plain radiographs may demonstrate appearances typical of an intestinal obstruction.^1,5,12
If the diverticulum is distended, a gas-filled viscus seen in the right iliac fossa or the mid abdomen may provide a clue to the diagnosis.
The presence of an enterolith may further support the diagnosis.
When perforation is a complication, plain abdominal and upright chest radiographs may reveal features of a pneumoperitoneum.
Although a conventional small-bowel barium meal is usually not helpful in routinely depicting Meckel diverticulum in many patients, the anomaly can be detected if careful technique is applied.^1,4 Some limitations encountered by using barium series are the overlapping of small bowel loops, the inability to achieve adequate distention, and the failure to adequately depict the mucosal pattern in the distal ileum. The yield improves with meticulous technique and spot compression imaging. The diagnostic yield is also improved with enteroclysis.
Barium enema study probably reveals most Meckel diverticula when sufficient reflux is achieved into the terminal ileum.¹³
Typically, the diverticulum is depicted as a contrast-filled outpouching, 0.5 to 20 cm long, that is located on the antimesenteric border of the ileum and has a junctional-fold pattern. The site of origin of a Meckel diverticulum rests on the demonstration of its junctional-fold pattern at the site of attachment. The characteristic junctional-fold appearances are a triradiate fold pattern, in which the loops are collapsed, and a mucosal triangular plateau, in which the loops are distended.
An inverted Meckel diverticulum without an intussusception, which occurs in 20% of patients, appears as an elongated, smoothly marginated, clublike intraluminal mass parallel to the long axis of the ileum.
Rarely, a gastric rugal pattern, intraluminal filling defects, and mucosal irregularity are identified. These are suggestive of ectopic gastric mucosa.

Degree of Confidence

Findings on plain abdominal radiographs are nonspecific. A conventional small-bowel barium examination has a low yield because the diverticula fill transiently and surrounding loops of small bowel tend to overlap and obscure the diverticula.¹³ Enteroclysis can detect as many as 50% of Meckel diverticula. Retrograde small-bowel examination probably helps in detecting most Meckel diverticula because of the distal location.

False Positives/Negatives

The neck of the diverticulum may become occluded by inflammation, which makes it difficult for the diverticulum to fill with barium; thus, a false-negative diagnosis may occur. Similarly, if the neck of the diverticulum is wide at the point where peristaltic activity tends to keep the diverticulum empty or partially filled, the result is a false-negative finding.

Demonstration of Meckel diverticulum does not necessarily mean that the diverticulum is the cause of symptoms. A barium examination involves simply filling the diverticulum with barium. In an actively bleeding patient, barium examination does not show whether the bleeding originates in the diverticulum. Rarely, a false-positive diagnosis may occur with acquired small-bowel diverticula (occurs in patients >40 y) and bowel duplications.

Computed Tomography

Findings

CT rarely is used as a primary imaging modality in patients in whom Meckel diverticulum is suspected. Most diagnoses made by using CT scans are incidental. An inverted Meckel diverticulum associated with an intussusception may be revealed as an intraluminal mass composed of a central area of fat attenuation representing the entrapped mesenteric fat of the inverted diverticulum, surrounded by a thick collar of soft-tissue attenuation.⁶

Degree of Confidence

Sufficient experience has not been gained to suggest the degree of confidence with CT.

False Positives/Negatives

Intussusception from other causes may appear similar to intussusception associated with Meckel diverticulum on CT scans.

Ultrasonography

Findings

The orifice of the diverticulum may become occluded. When this occurs, the wall becomes inflamed and the diverticulum is distended by fluid. Acute inflammation may mimic appendicitis. These diverticula are rarely revealed on sonograms, but they have been noted when they are distended by fluid. Sonographically, Meckel diverticulum may be identified when complications occur, such as a fluid-filled overdistended tube connected to the umbilicus. This tubular structure can be differentiated from an inflamed appendix because the former is larger and is located farther from the cecum. Two target signs of different sizes have been described in a double intussusception of the Meckel diverticulum into the ileum and the ileum into the colon.

Degree of Confidence

Occasionally, intussusception secondary to Meckel diverticulum has been diagnosed by using sonograms. However, the sensitivity and specificity of ultrasonographic examination generally is low. Ultrasonography is usually the first investigation used in young patients presenting with abdominal pain because it is noninvasive, but its role in evaluating gastrointestinal hemorrhage is limited.

False Positives/Negatives

The exact percentage of false-negative findings with diverticulitis and intussusception secondary to a Meckel diverticulum is unknown. Meckel diverticulitis and intussusception secondary to a Meckel diverticulum must be differentiated from appendicitis and other causes of intussusception.

Nuclear Imaging

Findings

The mucoid cells of the gastric mucosa secrete chloride into the intestinal lumen. Excretion does not depend on the presence of the parietal cells. Technetium-99m (^99m Tc)pertechnetate behaves in a manner that is analogous to halide anions (eg, chloride, iodide). The mucoid surface cells of gastric mucosa, whether located normally or ectopically, actively accumulate and secrete pertechnetate into the intestine. This is the basis for detecting ectopic gastric mucosa in symptomatic Meckel diverticulum.^8,9,14,15

Patient preparation is important to optimize results of this technique. This includes avoiding certain procedures, such as administration of cathartics (drugs that irritate the gastrointestinal tract), contrast-enhanced studies, endoscopy, and use of enemas for 48 hours prior to the procedure. The administration of certain drugs prior to scintigraphy improves results. These drugs include pentagastrin (which stimulates radionuclide uptake), cimetidine (which inhibits release of pertechnetate from the ectopic mucosa), and glucagon (which inhibits peristalsis). Because pentagastrin also increases motility, it may be most useful when used in conjunction with glucagon.

Degree of Confidence

Scintigraphy has an accuracy of 83-88%, a sensitivity of more than 85%, and a specificity of more than 95%. Sensitivity drops after adolescence.

False Positives/Negatives

False-positive results have been reported for a variety of reasons, including faulty technique, uptake at other sites of ectopic gastric mucosa (eg, in a gastrogenic cyst), and some enteric duplications. Occasionally, false-positive results are observed in a normal small bowel.

Vascular anomalies are a further source of false-positive findings, such as aneurysms, arteriovenous malformations, hemangiomas, and hypervascular tumors. Because^99m Tc pertechnetate is excreted by the kidneys, horseshoe kidneys, caliceal diverticulum, and urinary tract obstruction resulting from a variety of causes may cause false-positive scans. False-positive scans also may occur with a variety of bowel ulcerations, inflammations, and obstructions, including those due to duodenal ulcers, ulcerative colitis, Crohn disease, appendicitis, laxative abuse, intestinal obstruction, intussusception, and volvulus. These false-positive results are thought to be due to hyperemia caused by these conditions.

Careful attention to the timing of appearance of abnormal accumulations of pertechnetate can aid in distinguishing the false-positive causes from those due to ectopic gastric mucosa. The accumulations of pertechnetate due to hyperemia appear early in the study and tend to fade over time. The accumulations in ectopic gastric mucosa appear at, or nearly simultaneous with, the stomach and increase in intensity in parallel with the stomach. Lateral and oblique views are often helpful in differentiating the anterior location of a diverticulum from the posterior location of urinary activity.

False-negative scans may occur if the gastric mucosa mass within the diverticulum is insufficient or if intraluminal scintigraphic activity is diluted as a result of brisk hemorrhage or bowel hypersecretion. The quality of images is poor in patients who have received perchlorate or atropine.

Angiography

Findings

In patients presenting with acute gastrointestinal tract bleeding from a Meckel diverticulum, superior mesenteric angiograms may demonstrate not only the site of bleeding by focal contrast agent extravasation but also the cause of bleeding. Demonstration of the vitelline artery, which is an anomalous end branch of the superior mesenteric artery, is pathognomonic. The vitelline artery originates as an ileal branch of the superior mesenteric artery; this vessel is nonbranching and directed toward the right lower quadrant of the abdomen. This artery supplies the diverticulum via a network of tortuous and irregular small vessels likened to a basket-weave pattern. Superselective technique and the use of epinephrine are recommended to cause selective constriction of the normal splanchnic circulation for optimal depiction of the site of the lesion.¹¹

Degree of Confidence

Angiography has an accuracy of 59%.

False Positives/Negatives

Bleeding at a rate of 2-3 mL/min is required in adults for angiographic detection; higher rates of hemorrhage may be required in children for angiographic detection. Rarely, a Meckel diverticulum is supplied by branches arising from the ileocolic artery, which makes it more difficult to differentiate the causes of bleeding related to the cecum and ascending colon.

Intervention

When diagnostic angiography images depict severe gastrointestinal tract bleeding, superselective embolization should be considered so that surgery can be performed under stable conditions.^3,11,16

Medicolegal Pitfalls

Despite the reported sensitivity of radionuclide scanning, controversy remains regarding its use.
- Some clinicians believe that radionuclides have a limited role in the diagnosis of Meckel diverticulum and that imaging of all types should be replaced by laparoscopy, which offers the additional possibility of laparoscopic resection of a Meckel diverticulum.
- However, when used appropriately with meticulous technique in the appropriate age group, scintigraphy remains the best technique available for the diagnosis of a Meckel diverticulum.¹⁴
- The radiation dose to the patient is small and acceptable.
Laparoscopy is more invasive and poses a risk of morbidity.

See also the Medscape Resource Center Medical Malpractice and Legal Issues.

Multimedia

Media file 1: Diagram shows a Meckel diverticulum with vitelline ligament.

Media file 2: Diagram shows a cyst within a fibrous cord connecting the umbilicus to the intestine.

Media file 3: Diagram shows a patent vitellointestinal duct.

Media file 4: Diagram of a Meckel diverticulum.

Media file 5: Prone and supine radiographs of the right side of the abdomen obtained during an upper GI barium series in a 13-year-old boy shows the terminal small bowel and a Meckel diverticulum (arrow).

Media file 6: Technetium-99m pertechnetate scan in a 12-year-old boy who presented with intermittent dull abdominal pain and a mild iron deficiency anemia. On the present occasion, the pain appeared more severe and was associated with occasional vomiting; thus, the child was hospitalized. This 90-minute delayed image shows focal activity in the mid abdomen. The activity is more diffuse than is expected with Meckel diverticulum. At surgery, an inflamed Meckel diverticulum containing ectopic gastric mucosa was removed. The Meckel diverticulum had intussuscepted into the terminal small bowel.

Media file 7: Technetium-99m pertechnetate scan in a 12-year-old boy who presented with intermittent dull abdominal pain and a mild iron deficiency anemia. On the present occasion, the pain appeared more severe and was associated with occasional vomiting; thus, the child was hospitalized. This 90-minute delayed image shows focal activity in the mid abdomen. The activity is more diffuse than is expected with Meckel diverticulum. At surgery, an inflamed Meckel diverticulum containing ectopic gastric mucosa was removed. The Meckel diverticulum had intussuscepted into the terminal small bowel.

Media file 8: Technetium-99m pertechnetate scan in an 8 year-old boy who presented with iron deficiency anemia. The scan shows intense activity just above the urinary bladder, which was thought to represent an end-on Meckel diverticulum. The surgical specimen confirmed this finding.

References

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Ariga M, Suga K, Matsunaga N, et al. Failure to detect a huge Meckel''s diverticulum with abundant ectopic gastric mucosa on gastric mucosal scintigraphy with Tc-99m pertechnetate. Clin Nucl Med. May 2001;26(5):470-1. [Medline].
Ford PV, Bartold SP, Fink-Bennett DM, et al. Procedure guideline for gastrointestinal bleeding and Meckel''s diverticulum scintigraphy. Society of Nuclear Medicine. J Nucl Med. Jul 1999;40(7):1226-32. [Medline].
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Emamian SA, Shalaby-Rana E, Majd M. The spectrum of heterotopic gastric mucosa in children detected by Tc- 99m pertechnetate scintigraphy. Clin Nucl Med. Jun 2001;26(6):529-35. [Medline].
Linebarger JS, Roy ML. Focus on diagnosis: common nuclear medicine studies in pediatrics. Pediatr Rev. Nov 2007;28(11):415-7. [Medline].
Delle Chiaie L, Neuberger P. Early prenatal sonographic detection of an uncomplicated Meckel diverticulum. Ultrasound Obstet Gynecol. Oct 2007;30(5):790-1. [Medline].
Mitchell AW, Spencer J, Allison DJ, Jackson JE. Meckel''s diverticulum: angiographic findings in 16 patients. AJR Am J Roentgenol. May 1998;170(5):1329-33. [Medline].
Navarro O, Dugougeat F, Kornecki A, et al. The impact of imaging in the management of intussusception owing to pathologic lead points in children. A review of 43 cases. Pediatr Radiol. Sep 2000;30(9):594-603. [Medline].
Nolan DJ. The true yield of the small-intestinal barium study. Endoscopy. Aug 1997;29(6):447-53. [Medline].
Omar AM, Al-Saee''d TA, Elgazzar A. Scintigraphic pattern of intestinal duplication on a Meckel''s diverticulum scan. Clin Nucl Med. Oct 1998;23(10):708-9. [Medline].
Swaniker F, Soldes O, Hirschl RB. The utility of technetium 99m pertechnetate scintigraphy in the evaluation of patients with Meckel''s diverticulum. J Pediatr Surg. May 1999;34(5):760-4; discussion 765. [Medline].
Okazaki M, Higashihara H, Yamasaki S, et al. Arterial embolization to control life-threatening hemorrhage from a Meckel''s diverticulum. AJR Am J Roentgenol. Jun 1990;154(6):1257-8. [Medline].

Keywords

Meckel's diverticulum, Meckel diverticula, diverticulum of the ileum, intestinal obstruction, intestinal hemorrhage, hernia of Littre

Contributor Information and Disclosures

Author

Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP, Chairman of Medical Imaging, Professor of Radiology, NGHA, King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia
Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP is a member of the following medical societies: American Institute of Ultrasound in Medicine, Radiological Society of North America, Royal College of Physicians, Royal College of Physicians and Surgeons of the United States, Royal College of Radiologists, and Royal College of Surgeons of England
Disclosure: Nothing to disclose.

Coauthor(s)

Muthusamy Chandramohan, MBBS, DMRD, FRCR, Consultant Radiologist, Bradford Teaching Hospitals, UK
Disclosure: Nothing to disclose.

Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute
Sumaira MacDonald, MBChB, PhD, MRCP, FRCR is a member of the following medical societies: British Medical Association, Royal College of Physicians, and Royal College of Radiologists
Disclosure: Nothing to disclose.

Medical Editor

Robert J Starshak, MD, Medical Director, Assistant Clinical Professor, Department of Radiology, Medical College of Wisconsin, Falls Medical Group
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

David A Stringer, BSc, MBBS, FRCR, FRCPC, Professor, National University of Singapore; Head, Diagnostic Imaging, KK Women's and Children's Hospital, Singapore
David A Stringer, BSc, MBBS, FRCR, FRCPC is a member of the following medical societies: British Columbia Medical Association, Canadian Association of Radiologists, European Society of Paediatric Radiology, Ontario Medical Association, Radiological Society of North America, Royal College of Physicians and Surgeons of Canada, Royal College of Radiologists, and Society for Pediatric Radiology
Disclosure: None None None

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

John Karani, MBBS, FRCR, Consulting Staff, Department of Radiology, King's College Hospital, London
Disclosure: Nothing to disclose.

Further Reading