What Is Meckel's Diverticulum?

Overview

Meckel's diverticulum is a rare condition where a bulge forms in the lower part of the small intestine. It occurs when a tube in the umbilical cord fails to close properly during development. This condition is considered the most common congenital (present at birth) anomaly affecting the gastrointestinal tract. However, in general, it is uncommon, affecting only about 2% of the population, up to 4 times more frequently in males compared to females.^1,2

The Meckel's diverticulum may be attached to the belly button with a fibrous band. The walls of the bulge are similar to those of the small intestine. However, in some cases, it may also contain cells from the stomach or pancreas and, more rarely, hepatobiliary, duodenal, colonic, and endometrial tissue. The extent of complications in Meckel's diverticulum is associated with the presence of those abnormal cells.

In most cases, this bulge, which is typically around 2 inches long, does not cause any symptoms and is often discovered incidentally during abdominal surgery or less frequently on diagnostic imaging. However, in certain complicated cases, which usually occur in the first years of life, it needs urgent medical attention.

Causes of meckel's diverticulum

During the development of an embryo, there is a connection called the omphalomesenteric (or vitelline) duct between the digestive system and the yolk sac. Normally, this connection should close by the 6th to 7th week of pregnancy. However, if it doesn't fully close, a bulge known as a diverticulum can develop close to the ileocaecal valve that separates the small intestine from the large intestine. The exact cause of this anomaly is still unknown. While Meckel's diverticulum is not likely to run in families, it is more common in children born with certain birth defects affecting the belly button, digestive system, nerves, or heart.³

Signs and symptoms of meckel's diverticulum

Meckel's diverticulum typically remains asymptomatic, and it is often an incidental finding. However, when symptoms do occur, they can manifest at any age, with a higher frequency observed in childhood, usually around the age of 2.⁴ Symptomatic cases are more commonly observed in males.

Bleeding is the most common complication of Meckel's diverticulum, with a higher occurrence in younger children, affecting approximately 50% of cases.⁵ The bleeding happens when the inner lining of the diverticulum develops ulcers because of acid production by the ectopic gastric mucosa. The bleeding can be chronic and slow or sudden and massive. In children, it often causes painless rectal bleeding and dark red or maroon stools. In adults, it can lead to black, tarry stools called melena. Patients may also experience weakness and anaemia as a result of the bleeding.

Intestinal obstruction, another serious complication of Meckel's diverticulum, is more frequently observed in adults compared to children. Patients with intestinal obstruction experience symptoms like abdominal pain, distention, bloating, constipation, nausea, and vomiting. Obstruction can happen in different ways. The small bowel can twist around the fibrous cord associated with Meckel's diverticulum, causing Volvulus. The diverticulum may also cause the intestine to fold into itself. This is known as intussusception and usually occurs in children, who may also present with a palpable lump in the lower abdomen and currant jelly stools. Meckel's diverticulum can also get stuck in the abdominal wall or an internal hernia. 

The inflammatory process, due to infection or blockage, is a common complication in adults with Meckel's diverticulum. Around 20% of adults may experience diverticulitis, which can be challenging to distinguish from acute appendicitis. Typical symptoms include abdominal cramps and tenderness around the belly button, but more toward the middle compared to appendicitis.  If left untreated, diverticulitis can lead to perforation with peritonitis, which is a life-threatening emergency.

Management and treatment for meckel's diverticulum

The management of patients with suspected Meckel's diverticulum depends on their clinical presentation. The approach varies between symptomatic and asymptomatic cases.⁶

If Meckel's diverticulum is incidentally detected in imaging studies, no treatment is necessary. However, if it is discovered during a surgical procedure, it is recommended to resect the diverticulum in most children and young adults who are otherwise healthy. For adults under 50 years old, resection is needed for the diverticula that have a high risk of complications. However, for adults over 50 years old, no treatment is typically required.

Symptomatic cases of Meckel's diverticulum, which can present with haemorrhage, intestinal obstruction, herniation, or diverticulitis, are indications for surgical resection. 

Two main surgical procedures may be considered for the treatment of Meckel's diverticulum. The first is a simple diverticulectomy, which involves removing the diverticulum at its base. The second is a segmental resection of the intestine, including the diverticulum, followed by end-to-end anastomosis - reconnecting the healthy ends of the intestine together. These operations can be performed using either an open or a laparoscopic surgical approach. The choice between the two approaches is based on the individual patient's clinical condition and needs.⁷

Diagnosis of meckel's diverticulum

Meckel's diverticulum is challenging to diagnose due to its non-specific symptoms, which can overlap with other conditions. It is sometimes discovered incidentally during imaging laparoscopy or laparotomy; however, in symptomatic cases where the symptoms point towards Meckel's diverticulum, doctors may order certain tests. 

Merkel's scan

A test where a radioactive substance called technetium ( 99mTc) is injected into the bloodstream. X-rays are then taken to detect areas with acid-secreting cells where the substance has been absorbed, including ectopic gastric mucosa found in Meckel's diverticulum. Meckel’s scan is the most commonly used technique for diagnosis. 

Mesenteric arteriography and CT angiography

Both can show the presence of an anomalous vitelline artery supplying blood to the diverticulum or detect contrast extravasation in cases of bleeding.

Double balloon enteroscopy 

A procedure where a long tube with a camera is inserted through the mouth or rectum to examine the entire small bowel. It confirms the diagnosis by providing a direct visual inspection and can also identify any complications associated with Meckel's diverticulum.

Capsule endoscopy 

It is a procedure where a small capsule with a tiny camera is swallowed to capture pictures of the gastrointestinal tract. It helps doctors examine the intestine for abnormalities, like Meckel's diverticulum, as a possible cause of gastrointestinal bleeding.

Exploratory laparoscopy

A surgical procedure that can effectively locate and remove Meckel's diverticulum. However, it is generally not performed as the initial step in diagnosis.  Simple blood tests, such as a complete blood count (CBC), are done to check for anaemia. Another test, called the faecal occult blood test (FOBT), is performed to detect hidden gastrointestinal bleeding.

FAQs

How common is meckel's diverticulum?

Meckel's diverticulum is a relatively rare condition. It is present in about 2% of the population.

How can I prevent meckel's diverticulum?

There are no specific recommendations or guidelines to prevent Meckel's diverticulum because the exact cause related to its development in the embryo is still unknown.

When should I see a doctor?

It is important to seek medical attention if you have symptoms such as abdominal pain, gastrointestinal bleeding, bowel obstruction, or any other unusual or persistent symptoms related to Meckel's diverticulum. Remember, early detection and timely medical care play a significant role in managing Meckel's diverticulum effectively and minimizing potential complications.

Summary

Meckel's diverticulum is a rare congenital disorder caused by the imperfect closure of the omphalomesenteric duct during embryological development. It manifests as a protrusion near the ileocaecal valve. Meckel's diverticulum is thought to be the most common gastrointestinal birth defect despite its low prevalence. Complications, including gastrointestinal bleeding, bowel obstruction, herniation, and diverticulitis, can occur, even though many cases remain undetected and stay asymptomatic. Meckel diverticulitis patients may experience pain resembling appendicitis. The majority of symptomatic patients are children under the age of two. Diagnosing the condition can be challenging, but various tests play a crucial role in confirming its presence. The technetium-99m pertechnetate scan is the most effective diagnostic technique in cases of bleeding. The best management strategy will depend on the clinical signs, which frequently call for surgical intervention in symptomatic instances. The surgical procedures may involve either a simple diverticulectomy, removing the diverticulum at its base, or a segmental resection of the intestine with end-to-end anastomosis. The choice of procedure depends on individual patient factors and can be performed using open or laparoscopic approaches.  Prompt diagnosis and effective treatment are crucial to reduce the likelihood of serious consequences associated with Meckel's diverticulum. If you suspect you or a loved one may have Meckel's diverticulum, it is important to seek medical attention promptly.