Brief overview
- What is an intussusception? An intussusception (a piece of intestine pushes itself into the next section of intestine). Babies in the first year of life are usually affected. If left untreated, an intussusception can become life-threatening.
- Causes & risk factors: Cause mostly unknown; otherwise e.g. viral infections, intestinal diverticula, intestinal polyps, intestinal tumors, bleeding under the intestinal mucosa in certain vasculitis; also possible connection with cystic fibrosis and vaccination against rotaviruses; possibly obesity as a risk factor
- Symptoms: mainly acute, severe abdominal pain, repeated vomiting, pale skin, possibly bloody, slimy diarrhea
- Possible complications: Intestinal obstruction, intestinal perforation, death of the affected intestinal sections, inflammation of the peritoneum
- Diagnosis: palpation, ultrasound
- Treatment: usually conservative by introducing saline solution or compressed air into the bowel, surgery if necessary.
What is an intussusception?
Invagination is the medical term for an intestinal protrusion. This means that a section of the intestine protrudes into the part of the intestine behind it. In most cases, the lower section of the small intestine (ileum) slides into the upper section of the large intestine (cecum). This is referred to as an ileocecal invagination.
However, invaginations within the small or large intestine are also possible. However, they occur much less frequently.
Intestinal invagination occurs mainly in children. In eight out of ten cases, intussusception occurs in babies in the first year of life. Boys are affected slightly more frequently than girls.
Adolescents and adults suffer intussusceptions less frequently. This is usually a so-called ileoileal intestinal invagination, in which the last section of the small intestine (ileum) is invaginated.
In children, however, the ileocecal form predominates (the last section of the small intestine invaginates into the first section of the large intestine).
Invagination: What are the symptoms?
Intestinal invagination often triggers the following symptoms (children, adults):
- sudden onset of severe, cramp-like abdominal pain (the peak of pain can even lead to shock symptoms)
- palpable cylindrical structure on the abdomen
- Raspberry jelly-like stool (late symptom)
- skin pallor
- Repeated, sometimes bilious vomiting
Affected babies and toddlers may cry continuously due to the pain. Crying attacks during sleep are also possible. Due to the pain, they may adopt a resting posture with their legs drawn up.
Complications
If intussusception is not treated, life-threatening complications can occur, for example
- Dehydration (dehydration) with repeated vomiting
- Lack of blood supply, followed by death of the affected bowel sections
- Intestinal obstruction
- Peritonitis (inflammation of the peritoneum)
Intestinal intussusception: causes & risk factors
The origin of most intussusceptions remains unknown (idiopathic intussusception), especially in children aged between six months and three years.
Sometimes viral infections play a role, such as infections with adenoviruses (pathogens of gastrointestinal infections, among others) or noroviruses (pathogens of diarrhea): Intestinal movement (intestinal peristalsis) is increased during these infections. In addition, the Peyer’s patches (accumulations of lymph follicles in the mucous membrane of the small intestine) can enlarge and the lymph nodes in the abdominal cavity can swell due to inflammation. This can disrupt the movements of the bowel and lead to intussusception.
Isolated cases of intussusception have also been described in connection with a Sars-CoV-2 infection.
Occasionally, anatomical causes are behind an intussusception (especially after the age of 3). These include, for example
- Meckel’s diverticulum: a congenital, sac-like protrusion of the small intestine wall
- Intestinal duplications: malformations in the (small) intestine in which parts of the intestine occur twice
- Adhesions in the intestinal area
- Space-occupying lesions: Intestinal tumors, intestinal polyps, lymphomas (malignant tumors of the lymphatic system) – they are increasingly the cause of intussusception with increasing age
In some cases, there is a connection with cystic fibrosis (mucoviscidosis): Intestinal invagination can occur repeatedly up to the age of nine to twelve years.
A slightly increased risk of intussusception is also associated with rotavirus vaccination. According to studies, there are a few additional cases of intussusception among vaccinees compared to babies who have not received this oral vaccine. However, the benefit of the vaccination is significantly greater than the risk of intussusception. Experts recommend starting and completing the rotavirus vaccination series as early as possible (the first dose can be given from 6 weeks of age).
If a baby shows possible signs of intestinal invagination (severe abdominal pain, repeated vomiting, etc.) in the days following the rotavirus vaccination, parents should take the baby to the doctor immediately.
It is possible that obesity may promote the occurrence of intussusception.
Intestinal invagination: examinations & diagnosis
The doctor can detect an intussusception with certain examinations. The first indications are cylindrical thickenings on palpation of the abdomen. The abdominal wall may also show a defensive tension. If the doctor palpates the rectum carefully with a finger (rectal examination), blood may be found on the finger.
Invagination: Treatment
The treatment of intussusception is usually conservative, but surgery can also be performed if necessary.
Conservative treatment
In so-called hydrostatic disinvagination, saline solution is introduced via the anus using a catheter under ultrasound guidance in order to return the intussusception to its original position. The procedure is particularly successful if the symptoms have only been present for a few hours.
An alternative is pneumatic disinvagination: here, compressed air is pressed into the intestine via the anus using a catheter in order to remove the invagination. The patient is x-rayed during the procedure for monitoring purposes. This has the disadvantage of exposing the patient to radiation. In addition, the risk of the intestinal wall breaking through (perforation) is somewhat higher with this compressed air method compared to the saline method.
After conservative treatment of the intussusception, patients must be monitored by a doctor for around 24 hours. Both procedures can lead to relapses (recurrences) after successful completion.
Operation
During the procedure, the intussuscepted section of bowel is carefully repositioned manually (reduction) and possibly fixed in place to reduce the risk of recurrence. The whole procedure can be performed as part of a laparoscopy or via open surgery (with a larger abdominal incision).
If repositioning is not possible or the intussuscepted section of bowel has already died (necrosis), it must be removed in open surgery. This is also necessary if, for example, an intestinal tumor is the cause of the intussusception. The ends remaining after the affected section of bowel has been cut out are joined together so that the intestinal tube can pass through again.
The risk of recurrent intussusception is lower after surgical treatment than after conservative treatment.
