What Is Meckel's Diverticulum?

Meckel's diverticulum is a bulge or outpouching in the last part of the small intestine, which is called the ileum. It is a condition that is present at birth (also called a congenital condition) and is the result of an incomplete process in the development of the fetus.

Most people who are born with Meckel’s diverticulum don’t have any symptoms and may not know that they have one. It’s estimated that between 2% and 4% of people are born with a Meckel's diverticulum, making it the most common congenital condition affecting the digestive system. This condition doesn't always require treatment, and in some cases, it may be treated with surgery.

Meckel's Diverticulum Symptoms

In most cases, Meckel’s diverticulum does not cause any symptoms. When symptoms occur, they may come and go.

The signs and symptoms of Meckel’s diverticulum can include:

• Abdominal pain or cramping
• Abdominal tenderness, especially near the navel (belly button)
• Anemia
• Bleeding in the digestive tract
• Black or bloody stool
• Bowel obstruction (blockage)
• Diverticulitis (inflammation in the diverticulum)
• Nausea
• Vomiting

For children under the age of 5 years, bleeding in the digestive tract is the most common symptom. This is due to the stomach acid that is released by the diverticulum and causes ulcers in the small intestine.

Older children may experience a bowel obstruction, where stool is unable to pass through the intestines. Adults may also experience symptoms if they have not had surgery to repair the diverticulum. 

If a child or adult has any of the signs and symptoms, it's important to make an appointment to see a healthcare provider. If the symptoms are severe, urgent medical attention is needed.

Causes

Meckel's diverticulum is a malformation of the small intestine and it is formed during gestation (while a baby is still developing). The Meckel’s diverticulum extends through all of the layers of the wall of the small intestine.

A structure called the omphalomesenteric duct or the vitelline duct connects the yolk sac of the embryo to the beginnings of the digestive tract. Normally, this duct is replaced by the placenta between the fifth and seventh week of gestation. If the duct is not completely gone and fully replaced during that time, it can result in a Meckel's diverticulum.

Some variations:

• The diverticulum may be made of different types of cells, depending on the type that formed. If it formed from intestinal cells, which is true for the majority of cases, there might not be any symptoms or any symptoms that become bothersome enough to seek treatment. 
• A Meckel’s diverticulum may also form from stomach cells or pancreatic cells. In this case, there could be symptoms because these cells aren’t part of a normal small intestine and the symptoms would be expected to begin during infancy.
• Risk factors for having symptoms as an adult include being male, younger than the age of 50, having a diverticulum that is larger (bigger than 2 centimeters), the presence of ectopic tissue (tissue that is from outside the small intestine), a longer diverticulum (broad-based), and an attached fibrous band.

There are other conditions that can occur from a persistent vitelline duct, including a vitelline fistula.

Diagnosis

The symptoms of Meckel’s diverticulum are nonspecific, which can make the condition challenging to diagnose. If Meckel’s diverticulum is diagnosed, it usually happens during early childhood. Many cases are diagnosed before a child turns 10 years old but some are not found until the teenage years.

In some cases, an asymptomatic Meckel’s diverticulum may be diagnosed in an adult as an incidental finding. That is, it is found during an examination or treatment for another disease or condition.

Diagnostic Procedures

A test called technetium-99m pertechnetate scintigraphy is the one that’s most often done to diagnose a Meckel’s diverticulum. It’s also called a Meckel's scan. During this test, a substance called technetium-99m, which has a small amount of radiation in it, is injected into a vein. A gamma camera, which can detect radiation, is used to take a series of images of the abdomen. If the technetium-99m is inside the Meckel’s diverticulum, it will be seen on the images. This test is more helpful in diagnosing Meckel’s diverticulum in children than it is in adults.

Other tests that may be used either to try and make a diagnosis or to look for complications include plain radiography, barium studies, angiography, computerized tomography (CT), and ultrasonography. Direct visualization of the diverticulum can also be achieved by using double-balloon enteroscopy or video capsule endoscopy.

Exploratory laparoscopy, a type of minimally invasive surgery, may be used if the symptoms are severe and other less invasive tests are not diagnostic.

Treatment

If there are no symptoms, Meckel’s diverticulum might not need any treatment. This might be true if the diverticulum is found incidentally, such as during surgery or during the diagnostic process for another disease or condition.

If surgery is recommended, the diverticulum and a portion of the small intestine would be removed. Laparoscopic surgery will be preferred and used if that is a possibility. During this surgery, several small incisions are made and the surgery is done through the use of a tube that has a camera on the end.

Laparotomy (open surgery), which is done through the use of a larger incision, might be done in certain cases.

Prognosis

Once the Meckel’s diverticulum is removed, it can no longer cause symptoms. The diverticulum won’t return because it is a congenital defect that one is born with and not something that develops over time. 

Complications may occur in a small number of cases where there is ectopic tissue or there is fibrous tissue. If any of this tissue is left behind after removing the diverticulum, it may cause additional symptoms.

In most cases, there are no further complications.

Summary

Meckel's diverticulum is considered a common disorder. It often does not cause symptoms, and most of the time won’t require treatment. Diagnosis can be a challenge, but when a diverticulum is diagnosed, surgery can be done to remove it. Children and adults who have surgery to remove and repair Meckel's diverticulum usually make a full recovery.