Meckel’s diverticulum is an out pouching from the intestine caused by an abnormality during the development of the fetus and it occurs between 5 and 7 weeks after conception. A Meckel’s diverticulum contains all the normal intestinal layers. This out pouching has its own blood supply. Variations of this abnormality include a blind ending passage from the belly button or umbilicus, called a sinus, or a cyst inside the abdominal cavity. In other instances, there may be a cord-like attachment from the undersurface of the umbilicus to the intestine and the intestine may twist around the band resulting in blockage of the intestine (Figure 1).
Figure 1: Various vitelline duct (the connection between the belly button and the intestine) abnormalities. A, Vitelline duct sinus. The portion of the vitelline duct attached to the intestine has disappeared as is typical. However, a sinus tract remains opening into the umbilicus (belly button). B, Meckel’s diverticulum. The umbilical portion of the primitive vitelline duct has disappeared, leaving a diverticulum or outpouching communicating with the normal small intestine. The diverticulum can bleed, become inflamed, rupture, and act as the point from which an intussusception (the upstream intestine moves inside the downstream intestine) can occur. C, Persistent cord of scar. The vitelline duct can be completely replaced by scar tissue; however, a twist around this band can result in intestinal blockage. D, Vitelline duct cyst. A fluid-filled, cystic structure may occur when the umbilical and the intestinal ends of the duct disappear but the central portion remains open. E, Patent vitelline duct. There may be an opening from the belly button to the intestine which is characterized by passage of gas or drainage from the umbilicus. F, Prolapse. Occasionally the intestine may pooch out through an open vitelline duct.
Meckel’s diverticulum is the most common congenital anomaly (abnormality) of the gastrointestinal tract (stomach and intestines) and is present in approximately 2% of the population. There are frequently other congenital abnormalities, such as heart problems, abdominal wall muscle abnormalities, intestinal problems, and Down syndrome. More than 70% of patients who are symptomatic (who have problems) from a Meckel’s diverticulum have abnormally located tissue resembling the lining of the stomach within the tip of the diverticulum; another 5% have abnormally located pancreatic tissue in the diverticulum (Figure 2). For the 95% of patients who are not symptomatic, the occurrence of abnormal tissue, such as stomach or pancreas, in the diverticulum is less than 15%.
The “rule of 2” often is cited in association with Meckel’s diverticulum: 2% occurrence, two types of abnormal lining (stomach and pancreas), located within 2 feet of the junction of the small and large intestine, approximately 2 inches in length, and usually symptomatic by 2 years of age. Symptoms result primarily from bleeding into the intestine (40%), blockage of the intestine (35%), or inflammation (reaction by the body) (17%) (Table 1). Symptoms vary indirectly with patient age (Table 2). In newborns, blockage of the intestine is the most common presentation, whereas bleeding is noted more frequently in slightly older infants and young children. More than 95% of Meckel’s diverticula do not cause symptoms. Surgical removal is indicated if symptoms occur. If there are no symptoms some surgeons may still recommend surgical removal in children.
Table 1. Meckel’s Diverticulum: Incidence of Complications
Table 2. Meckel’s Diverticulum: Age at Presentation (n = 217)
The most common symptom of a Meckel’s diverticulum is a large amount of intestinal bleeding, usually in children younger than age 5 years. The stools are characteristically maroon in color and unassociated with vomiting of blood. In many cases, bleeding subsides for a period but recurs intermittently. Bleeding is occasionally excessive and may require blood transfusion. Although spontaneous stoppage of bleeding is the general rule, occasionally life-threatening bleeding may occur.
The second most common presenting symptom with Meckel’s diverticulum is intestinal blockage. This usually occurs in the first few months of life. This is treated by surgery and surgical correction including surgical removal of the outpouching. Twisting of the intestine around a band may be associated with reduced blood supply to the intestine.
The third most common presentation of Meckel’s diverticulum is inflammation, which usually gives a clinical picture similar to that of appendicitis. If the appendix is normal at the time of surgery for suspected appendicitis, a careful search for a Meckel’s diverticulum should be made. The inflammation often is related to the abnormally located stomach lining or the pancreatic tissue in the diverticulum. This inflammation can cause a hole in the intestine with spread of infection in the abdominal cavity or a localized pus pocket or abscess. These patients require intravenous fluid and preoperative antibiotic therapy. Inflammation of the Meckel’s diverticulum is treated by surgical removal. Occasional reports have described foreign bodies (e.g., fish or chicken bones) stuck in a Meckel’s diverticulum. Stones also have been reported, and even parasitic infections have been observed in diverticula on rare occasions.
Intestinal cancer has been reported sporadically in patients with Meckel’s diverticula. These cancers are observed very rarely in children and are more often seen, though still rare, as a complication in adults.
Figure 4: The diagnosis of Meckel’s diverticulum can be obtained by a technetium-99m scintiscan. The radioactivity can be seen in the stomach and bladder, and the diverticulum is seen in the midabdomen.
Injection of dye into the outer opening in the umbilicus usually shows the dye extending into the intestine on x-ray examination if there is a connection between the pouch and the navel. The diagnosis of bleeding Meckel’s diverticulum may be made by a special scan, which shows the abnormally located stomach lining within the outpouching (Figure 4).
Administration of special medications and using antacids make the test more accurate. This scan should be the initial test performed when Meckel’s diverticulum is suspected. If the patient is actively bleeding, other special tests to look for bleeding, such as bleeding scans, angiography, colonoscopy, and/or upper gastrointestinal endoscopy, may need to be performed.
When the diagnosis of a symptomatic Meckel’s diverticulum has been established, surgical removal of the lesion should be performed. Simple removal with closure of the intestine is satisfactory treatment for most patients. For Meckel’s diverticulum with inflammation and a hole in the out pouching, removal of the outpouching is recommended. If there is an ulcer of the intestine at the base of the outpouching, removal of the outpouching as well as a piece of the intestine with reconnection of the normal intestine is recommended.
Although complications of Meckel’s diverticulum rarely may be life-threatening, studies of large numbers of patients with this problem have been associated with a low risk of complications or death (<2%), related largely to the management of the diverticulum itself. The most common complication after removal of a Meckel’s diverticulum is intestinal blockage from scar tissue, occurring in 5% to 9% of patients. The risk of death from surgical removal in a patient who is not symptomatic should approach zero. The reported risk of death for the complications of the Meckel’s diverticula themselves ranges from 1% to 10%.
Article and graphics adapted from O'Neill: Principles of Pediatric Surgery. © 2003, Elsevier.