What Is Meckel's Diverticulum?

Meckel's diverticulum is an abnormal pouch in the wall of the small intestine, close to the area where the small and large intestines join. It is the most common congenital anomaly (anatomical difference present at birth) of the gastrointestinal system.

This condition usually doesn't cause symptoms and a person may never know they have it. But it can sometimes lead to serious bleeding, bowel obstruction, and infection (Meckel's diverticulitis).

This article discusses Meckel's diverticulum, including who it affects and what surgical treatment entails.

What Causes Meckel's Diverticulum?

No one knows why some people have Meckel's diverticulum. It is a condition present at birth, though it does not appear to run in families.

The pouch forms from a type of digestive system tissue that's usually absorbed before birth. It's a remnant of the vitelline duct, which connects the intestines to the fetus's umbilical cord. The pouch usually contains the same type of tissue as the stomach and pancreas, rather than intestinal tissue.

Who Gets Meckel's Diverticulum?

Anyone can be born with Meckel's diverticulum. It is seen in people of any sex. Research shows males are more likely to develop symptoms, which are most common in young children under age 4, with the risk decreasing over time. However, symptoms can develop at any age.

(Note that when citing research or health authorities, the terms for sex or gender from the source are used.)

People with other congenital anomalies, including in the esophagus (food tube), rectum, and anus, may be more likely to have Meckel's diverticulum. It may also be linked to defects in the nervous and cardiovascular systems.

How Common Is Meckel's Diverticulum?

Meckel's diverticulum is estimated to occur in about 2% of the population or about 1 in every 50 people. However, the actual percentage may be higher because many people don't know they have it unless they develop symptoms.

Sometimes it's found during a medical imaging study such as magnetic resonance imaging (MRI), but Meckel's diverticulum often goes undetected.

Children

Infants and very young children with Meckel's diverticulum are most likely to develop symptoms. Meckel's diverticulum is the most common cause of massive bleeding from the lower intestinal tract in children under 2.

The average age at which symptoms develop is around age 2. As a child grows older, the likelihood of symptoms developing decreases.

Adults

Though symptoms from Meckel's diverticulum are unusual in adults, they can happen at any age. The likelihood of someone developing symptoms over their lifetime if they have Meckel's diverticulum is about 4%. Males tend to have a higher complication rate than females, with the most common complication being bowel obstruction.

Symptoms and Complications

Though most people don't have symptoms from Meckel's diverticulum, the pouch can produce acid just like the stomach because it can contain the same type of tissue. The acid can irritate the intestinal lining and form an ulcer. If the ulcer ruptures, or if the pouch moves, it can cause the following symptoms and complications:

• Bleeding: In children, bleeding from the rectum is a common symptom. It is usually painless and can be bright red or passed in dark red, jellylike stools. It usually stops on its own, but you should always call your child's healthcare provider if you see this symptom. In adults, bleeding may make the feces look dark and sticky. Severe bleeding can lead to shock and be life-threatening.
• Nausea, vomiting, and abdominal pain: These symptoms may be present, especially if complications such as diverticulitis (inflammation), intestinal obstruction, or infection develop.
• Intestinal obstruction: This is a partial or complete blockage of the intestine. In both children and adults, small bowel obstruction is the most common complication seen when the condition presents symptoms.
• Abdominal infection: Waste leaking from the intestine can cause infection, including peritonitis (infection of the lining of the abdominal cavity and organs).

If bleeding, blockage, or infection develops, it can be a medical emergency. If someone is having severe abdominal pain, rectal bleeding that does not stop, or signs of infection or blockage, seek medical care immediately.

Why Are People Often Asymptomatic?

Most people will not develop symptoms from Meckel's diverticulum. Many of the pouches don't produce stomach acid even though they may contain some of the same kind of tissue as the stomach.

Any symptoms felt are due to complications. Complications can include ulcers that form from stomach acid production in the diverticulum or a twisting of the fibrous band that attaches to the umbilicus (navel). However, these are not expected to occur.

Conditions With Symptoms Similar to Meckel's Diverticulum

Healthcare providers may overlook symptoms of Meckel's diverticulum because it is rare and symptoms can closely resemble other conditions including appendicitis, peptic ulcers (an erosion in the lining of the stomach or small intestine), and Crohn's disease (a type of inflammatory bowel disease).

If the diverticulum becomes inflamed and results in diverticulitis, symptoms can be particularly hard to distinguish from those of an appendicitis attack. However, with diverticulitis, the pain and tenderness are located around the navel, whereas appendicitis pain begins in the middle of the abdomen and moves to the lower right side.

Crohn's disease can also cause rectal bleeding. Peptic ulcer disease symptoms similar to Meckel's diverticulum include abdominal pain and sometimes nausea and vomiting.

How Is Meckel's Diverticulum Diagnosed?

Though Meckel's diverticulum may never be diagnosed unless it causes symptoms, there are tests that can lead to a diagnosis. These include:

• Blood test: Labs can check for anemia or infection.
• Stool test: A stool sample may be checked for blood.
• Barium enema and small bowel X-rays: An enema containing the mineral barium is given. Barium makes the organs and any abnormalities show up more clearly on X-rays.
• Meckel's scan: A substance called technetium is given through an intravenous (IV) line. Technetium highlights stomach tissue in an X-ray, which Meckel's diverticulum may contain.
• Rectosigmoidoscopy: After sedation, a small tube with a camera at the end is inserted into the rectum and lower colon. It can detect bleeding, blockages, and other problems.

Surgical Treatment

If Meckel's diverticulum is not causing any symptoms but is discovered during an imaging study or another procedure, it is generally not removed. If a person has risk factors such as being male, being under age 50, having a longer diverticulum, or having a diverticulum with abnormal features, surgical removal may be considered. 

If Meckel's diverticulum is causing severe symptoms like hemorrhage or blockage, the pouch can be removed surgically. After general anesthesia, a surgeon performs either a minimally invasive procedure, which heals more quickly, or open surgery, which requires a larger incision.

In very severe cases, emergency surgery may be necessary to remove an obstruction, stop bleeding, and remove the intestinal pouch.

Prognosis After Meckel's Diverticulum Removal

Barring unusual surgical complications, the outlook for recovery from Meckel's diverticulum is very good. The source of the problem has been removed and the pouch will not grow back. Recovery time from surgery will vary according to factors including age, general health, and whether the procedure was minimally invasive or required a larger incision.

Summary

Meckel's diverticulum is the most common congenital anomaly of the digestive system. It is a pouch in the lower intestine that forms from tissue that is usually absorbed by the body before you are born. About 2% of the population has Meckel's diverticulum, but many people will never know they have it.

The condition does not harm your health unless it becomes inflamed (diverticulitis), bursts, or moves and blocks the intestine. Very young children are most likely to develop symptoms of painless rectal bleeding, but symptoms can develop at any age, and also include abdominal pain, nausea, and vomiting

A diagnosis may be overlooked because it is rare and mimics other abdominal conditions, including appendicitis. If severe symptoms develop, surgery can remove the pouch. In some cases, Meckel's diverticulum can become a medical emergency, due to hemorrhage, infection, or bowel obstruction.