What is Meckel Diverticulum?
A Meckel diverticulum happens when there’s a failure to properly close off a certain area in the baby’s developing intestinal tract. This condition is the most commonly occurring birth defect of the gastrointestinal (stomach and intestines) system. This issue results in a small bulge or pocket in the small intestine, often referred to as a Meckel Diverticulum. However, many people with this condition don’t show any symptoms.
In some cases, this small intestinal pocket can produce acid, leading to stomach bleeding and stomach pain. A simplistic way to understand this condition is through the “rule of 2s”. This basically means that a Meckel diverticulum is found in 2% of the population, symptoms show in 2% of those affected, it usually affects children under 2 years old, appears twice as likely in males than females, is located about 2 feet away from a specific valve (the ileocecal valve) in the intestines, is usually less than 2 inches long, and this bulge can have 2 types of tissue lining found inside.
What Causes Meckel Diverticulum?
Meckel’s diverticulum is a condition that happens during early development when a small duct, known as the omphalomesenteric duct, doesn’t completely disappear as it should. This duct is a kind of ‘life line’ between the yolk sac and the gut of the growing embryo, providing nutrition until the placenta is formed.
Normally, around the 7th week of pregnancy, the duct should disconnect from the intestine. But sometimes, it doesn’t disappear completely or at all, which can lead to several outcomes. If it becomes a closed pouch or cyst, that’s called an omphalomesenteric cyst. If it turns into a channel with an opening at the belly button, that’s called an omphalomesenteric fistula. And if it becomes a fibrous cord from the small pouch to the belly button, that can cause a blockage in the gut.
If the duct disconnects without any additional attachment, this forms a Meckel’s diverticulum. There’s an easy way to remember the typical features of this condition, called the “rule of 2s”. It’s the most common birth defect of the digestive system, happening in about 2% of babies. It usually measures 2 inches long and is typically found about 2 feet from the valve that separates the small and large intestine. It’s twice as common in boys. The pouch can also contain two types of tissue normally found in the stomach or pancreas.
A Meckel’s diverticulum is a true diverticulum, which means it contains all the layers of the small intestine’s wall. Sometimes, this little pocket can have tissue types that are not typically found in this part of the gut, the origin of which is unknown. It’s estimated that about 15% of patients will have this atypical tissue within the pouch.
Risk Factors and Frequency for Meckel Diverticulum
Meckel diverticulum is the most frequently occurring inborn abnormality of the digestive system. It doesn’t typically run in families. However, people with other abnormalities in the digestive, nervous, or cardiovascular system are at a higher risk of having a Meckel diverticulum. Around 2% of the general population is thought to have a Meckel diverticulum, but the exact numbers are hard to estimate because many people do not show symptoms. Often, symptoms begin to appear in the first ten years of life, typically around the age of 2.5.
Signs and Symptoms of Meckel Diverticulum
A Meckel diverticulum is a medical condition that often goes unnoticed. Many people who have it may never find out unless it is accidentally discovered during medical imaging tests. Symptoms, if they occur, usually appear in early childhood, typically around 2.5 years old. The most common symptom in young kids is painless rectal bleeding, which often looks like jelly or has a brick-like color. In adults, the bleeding may manifest as black, tarry stools. Luckily, the bleeding often stops on its own, as the body naturally tightens blood vessels to avoid further blood loss. A variety of other gastrointestinal symptoms may also occur.
Doctors may also consider Meckel diverticulum as a possible cause when kids keep having a specific type of bowel obstruction known as intussusception, or when someone shows symptoms of appendicitis even though their appendix has already been removed. It can also be a suspect in cases where adults have gastrointestinal bleeding with no apparent cause. Notably, even though we typically think of Meckel’s diverticulum causing painless bleeding, some people with the condition might also have abdominal pain.
Testing for Meckel Diverticulum
Meckel diverticulum is a medical condition that can be suspected in young children, particularly those under two, who experience painless bleeding from the rectum. This condition is actually responsible for about half of all lower gastrointestinal (GI) bleeding incidents in children of this age group.
Several tests can be used to identify a Meckel diverticulum. An abdominal x-ray typically doesn’t provide much useful information, and even procedures using barium (a type of contrast agent) often don’t show the diverticulum clearly. The best test for detecting a Meckel diverticulum is a specialized nuclear medicine study known as a Meckel radionuclide scan, or simply a Meckel scan.
In a Meckel scan, doctors inject a substance called technetium-99m into the patient’s body. This substance is absorbed by a type of tissue called ectopic gastric mucosa, which allows doctors to see the Meckel diverticulum clearly. Medications like cimetidine, ranitidine or glucagon can be used to enhance the absorption of the dye, thus increasing the effectiveness of the test.
In cases where the patient is actively bleeding, another type of nuclear medicine scan – a tagged red blood cell (RBC) scan – can be used to detect a Meckel diverticulum. A CT scan, which provides detailed images of the body’s internal structures, might show evidence of inflammation or blockage at the site of the diverticulum.
More invasive testing methods, such as angiography (a study of the blood vessels) and laparoscopy (a surgical procedure that involves a small incision and the use of a camera to look inside the abdomen), might also be used. However, these techniques are typically reserved for cases where other tests have been inconclusive or when the patient’s condition is unstable.
Treatment Options for Meckel Diverticulum
If you lose a lot of blood, it’s important to replace it. This may involve being hydrated with fluids or receiving a blood transfusion. Meckel’s diverticulum, a small pouch in the digestive tract, is typically treated with surgery if it’s causing symptoms. This small pouch is usually removed along with some areas of the small intestine next to it.
There are two common types of surgery for this: laparoscopic surgery or open surgery. Laparoscopic surgery is becoming more popular and is a technique where the surgeons make small cuts and use a camera to guide their work. Open surgery involves making a large cut to remove the pouch.
If a Meckel’s diverticulum is found by chance during surgery for another condition, but isn’t causing any symptoms, it’s unclear what the best course of action is. Some doctors suggest surgery to remove it, while others recommend watching it closely over time. Make sure to have a conversation with your healthcare provider to understand the best option for you.
What else can Meckel Diverticulum be?
When diagnosing the cause of gastrointestinal (GI) bleeding, especially in children, there are a lot of different conditions that doctors have to consider. It’s important to note that severe GI bleeding is rare in children. Sometimes, what looks like blood in a child’s stool could just be the impact of eating certain foods like spinach, or taking iron or bismuth. A special test can confirm whether or not there’s actually blood in the stool.
As for infants, they might have blood in their stool if they swallow their mother’s blood from her bleeding nipples, or if they are dealing with issues like a milk protein allergy, intussusception (where one part of the intestine slides into another part), or anal fissures (small tears in the lining of the anus).
Necrotizing enterocolitis, a serious intestinal disease, should also be considered, especially in newborns and prematurely born infants.
The common causes of rectal bleeding in older children include:
- Colitis (inflammation of the inner lining of the colon)
- Gastroenteritis (an infection in the stomach and intestines)
- Henoch-Schonlein purpura (HSP, a disease that causes inflammation and bleeding in the small blood vessels)
- Hemolytic uremic syndrome (HUS, a condition that affects blood clotting)
- Intussusception
- Inflammatory bowel disease (long-term inflammation of the digestive tract)
- Vascular malformation (abnormalities in blood vessels)
Possible Complications When Diagnosed with Meckel Diverticulum
The most frequent problem related to a Meckel diverticulum in children is rectal bleeding, which can lead to anemia. In adults, the most typical issue is an obstruction in the small intestine. This obstruction may be caused by multiple factors such as an omphalomesenteric band (a sort of tissue cord from the belly button to the small intestine), an internal hernia, a twisted intestine around leftover tissue from the vitelline duct, and intussusception (a condition where one part of the intestine folds into itself, with the diverticulum initiating this process). The diverticulum is also capable of becoming inflamed, resulting in a condition known as Meckel diverticulitis where it can rupture causing inflammation in the peritoneum (the lining of the abdominal cavity).
Common Side Effects:
- Rectal bleeding leading to anemia in children
- Small bowel obstruction in adults
- Causes of obstruction including the omphalomesenteric band, internal hernia, twisting of the intestine, and intussusception
- Inflammation of the diverticulum (Meckel diverticulitis)
- Possibility of rupture and inflammation in the abdomen (peritonitis)
