Meckel’s diverticulum, diverticulum ilei
Definition/Introduction
A Meckel’s diverticulum is a bulge (diverticulum) of the ileum or the jejunum. This bulge originates from embryonic development and represents a remnant (relic) of the yolk duct (Ductus omphaloentericus). The yolk duct is the embryonic connection between the yolk sac and the intestinal tube and usually (physiologically) recedes in the womb (more precisely in the 6th week of embryonic development). Usually, the Meckel’s diverticulum is located in the last 30-60cm of the small intestine.
Causes
The reason for the emergence or persistence of the Meckel’s diverticulum lies in an inadequate regression of the yolk duct (Ductus omphaloentericus), which was created during embryonic development. Since only about 2% of affected patients show symptoms of Meckel’s diverticulum, this intestinal protrusion is usually found by chance during open abdominal surgery (laparatomy) or laparoscopy. If, however, the symptoms in the abdominal area are unclear, a Meckel’s diverticulum should always be ruled out during open abdominal surgery.
Scintigraphy is another important procedure for the diagnosis of a Meckel’s diverticulum. In this procedure, radioactive substances (in this case sodium pertechnetate) are introduced into the body, which accumulate in the displaced (ectopic) stomach mucosa in the area of the Meckel’s diverticulum and can thus represent the intestinal protrusion. Other imaging techniques such as CT or MRI are not groundbreaking and are rarely used when a Meckel’s diverticulum is suspected.
Especially a Sellink MRI can diagnose a Meckel’s ́sches diverticulum. Here, an MRI is performed after oral administration of contrast medium. The diverticulum becomes visible through the contrast medium image.
Frequency distribution
In about 1.5-2% of the population a Meckel’s diverticulum can be found. About 60% of patients are infants under 2 years of age, with boys being affected about twice as often as girls. Usually the Meckel’s diverticulum does not cause any symptoms.
However, in about 2% of those affected, symptoms similar to appendicitis may occur. The symptoms are caused by an inflammation in the area of the Meckel’s diverticulum due to accumulated intestinal contents, which are a breeding ground for bacteria and other germs. The symptoms range from fever, nausea and vomiting to severe pain in the right half of the abdomen.
In about 30-50% of patients, gastric mucosa can be detected in the area of the Meckel’s diverticulum instead of the normally occurring small intestinal mucosa. Since the stomach mucosa has glands for the release of acid, which normally stimulate digestion within the stomach and fight germs, acid can now also be produced on the stomach mucosa in the area of the Meckel’s diverticulum. Consequently, the intestinal mucosa is attacked by the aggressive stomach acid and the development of intestinal mucosa defects (ulcers) with bleeding, intestinal perforations and peritonitis is promoted.
In the worst case, due to the intestinal rupture and the spread of intestinal germs in the normally sterile abdomen, a so-called “acute abdomen” can develop, resulting in severe pain, fever and a reduced general condition. This can ultimately lead to the germs spreading via the blood into the whole body (sepsis) and to shock. Another complication that can occur with a Meckel’s diverticulum is the so-called intussusception, which leads to intestinal wall invaginations in the area of the Meckel’s diverticulum.
The consequences are a disturbance of the blood supply to the corresponding intestinal segment and water retention (edema) in the intestinal wall. The symptoms in children arise from complete health and correspond to those of an intestinal obstruction (ileus): sudden severe abdominal pain, vomiting, paleness, shrill screaming of the infants, bloody-mucilaginous stool and cylindrical hardening of the intestine. In adults, these symptoms usually develop insidiously over a longer period of time and finally culminate in a partial or complete intestinal obstruction (ileus).
In addition, an intestinal obstruction (ileus) can also occur when the intestine is trapped by a connective tissue strand between the Meckel’s diverticulum and the navel (so-called bridge ileus).The symptoms are characterized by severe, cramping abdominal pain (colic) and other more unspecific signs of illness such as vomiting, stool retention, diarrhea or a severe deterioration in general condition. The treatment of a Meckel’s diverticulum is the surgical removal of the intestinal wall bulge (resection). This should be done both in case of complaints and in case of accidental findings during another abdominal operation. Although the opinions of physicians differ on the question of whether removal is necessary when there are no complaints, it is clear that inflammation, bleeding and other complaints can certainly be caused by a Meckel’s diverticulum and that one is on the safe side by removing the diverticulum. As a further therapeutic option, it is possible to combat the bleeding or inflammatory complications which can arise from the acid formation within the distended stomach mucosa in the area of the Meckel’s diverticulum by taking so-called proton pump inhibitors (PPI).
