What Is Intussusception?

Intussusception is a serious condition that occurs when a portion of the intestines moves inside itself (similar to how a telescope works) and causes a blockage. It is more common in infants and children than it is in adults. Intussusception can be life-threatening and requires immediate treatment.

Symptoms of intussusception can include abdominal pain, jelly-like, bloody stools, vomiting, diarrhea, and fever. The abdominal pain will come and go every 15 to 20 minutes, and infants and babies with intussusception that experience this pain will cry and pull their knees to their chest.

Intussusception can occur at any point in the digestive tract but is most often found to occur at the junction between the small and the large intestine.

Anatomy and Function of the Digestive System

The small intestine is a tube-like structure that connects the stomach and the large intestine. The large intestine, which is also tube-like, is connected to the small intestine via the ileocecal valve.

After food is chewed, swallowed, and passes through the stomach, it enters the small intestine where most vitamins and minerals are absorbed. The food is moved through the digestive system by the muscle contractions in the walls of the digestive tract that is called peristalsis.

Next, the partially digested food passes through the ileocecal valve and into the large intestine, where it continues to be broken down and water is absorbed. Finally, the waste material exits the body through the anus as a bowel movement.

An intussusception can block the movement of stool through the intestine, which could lead to serious complications, such as a hole in the intestine (a perforation).

Intussusception Symptoms

Intussusception is more common in infants and children and rarely occurs in adults. The symptoms may be similar but may be more challenging to identify in infants and children who aren’t able to tell their caregivers what’s happening. In adults, intussusception may be occurring along with other conditions and may, therefore, be difficult to diagnose.

Symptoms of intussusception include:

• Abdominal lump
• Abdominal pain that comes and goes every 15 to 20 minutes
• Diarrhea
• Fever
• Lethargy
• Stools that contain blood and mucus and may look like jelly
• Vomiting

Not every symptom will occur in every case of intussusception. The abdominal pain will start out coming and going but will get more intense and frequent as the condition progresses.

Some children, especially those that are older, may only have pain and not any other symptoms. Infants, however, may not cry or give other cues that they are in pain. Infants that do have abdominal pain may respond by crying and pulling their knees up to their chest. 

For adults, intussusception is rare and the symptom that’s most common is the intermittent abdominal pain, followed by nausea and vomiting. Because it’s challenging to diagnose in adults, some people may go quite some time before seeing a doctor.

When intussusception isn’t treated it could lead to a loss of blood supply to that part of the intestine. Without blood flow, the tissue in the intestine may start to die, leading first to a hole in the intestinal wall and then to a serious infection called peritonitis.

Peritonitis may cause abdominal swelling and pain, fever, lethargy or listlessness, abnormal breathing, and a weak or racing pulse. Peritonitis is a medical emergency and requires immediate treatment. 

Causes

There are a few different reasons that intussusception may occur, but most of the time there is no identifiable cause.

One possible cause of intussusception in children is a virus. Viruses have been found in the stool of children who have had intussusception. In addition, this condition seems to follow season variations like viruses do. That is to say, it happens more often during the times of the year when viruses are more commonly being spread from person to person.

Another possible cause of intussusception is a polyp, tumor, or abnormal growth in the small intestine. The normal contractions of the intestine are called peristalsis. They cause the intestine to move in a wave-like way. A section of the intestine may "grab on" to this abnormal growth (which is called a lead point) as it moves. What happens next is that piece of the intestine is hooked on that abnormal growth and when the wave motion occurs, the intestine can telescope over itself.

In children, the cause of intussusception is often unknown in up to 90% of cases. However, in some children the cause may be a Meckel’s diverticulum. This is an outpouching in the wall of the small intestine.

A Meckel’s diverticulum is present at birth (congenital). It is the most common congenital abnormality of the digestive tract, occurring in up to 2% of people. The diverticulum becomes the anchor that a piece of intestine grabs onto and starts to telescope.

In adults, intussusception could be the result of an abnormal growth (such as a polyp or a tumor). It could also occur because of scar tissue (adhesions) in the intestine, such as that which forms after having abdominal surgery.

Rarely (in 0.1–0.3% of cases), intussusception may occur after gastric bypass or other weight loss surgery. While also rare, intussusception with a lead point has also been seen in adults with Crohn’s disease.

Diagnosis

Intussusception might be suspected when an infant or child has abdominal pain and/or other symptoms. In order to make a diagnosis, a physician will palpate the abdomen, paying special attention to how the child reacts and to see if the abdomen is swollen or tender. A doctor may also be able to feel the location of the intussusception.

A diagnosis of intussusception is a medical emergency, and if the patient is not already in the emergency department, the next step will be to seek care there right away.

A plain abdominal X-ray will show a blockage but will not show an intussusception, and are therefore of limited use in diagnosis. However, the presence of a blockage that shows on an X-ray may offer more diagnostic clues.

An abdominal ultrasound is more useful in identifying an intussusception, especially in children. In adults an abdominal ultrasound is less helpful and therefore a computerized tomography (CT) scan might be used to make (or rule out) a diagnosis.

For children, a pediatric surgeon may be consulted in order to provide the best care. For adults and children who appear critically ill, surgery on the intestines may be done right away. 

Treatment

There are a few ways that an intussusception might be treated. There are two types of enemas that may help in reversing the intussusception. These treatments work in many cases but may need to be repeated in a small number of cases.

Air enema. An air enema is what it sounds like: air is introduced into the intestines. This is done by passing a tube through the anus and into the rectum. Air is moved through the tube and into the intestines. Then some X-rays are taken. The air helps the location of the intussusception be visible on the X-ray films. The air also serves as a treatment, as it helps push the telescoping part of the bowel and move it so that it is no longer folding in on itself. 

Barium enema. During this type of enema, barium is introduced through a tube that has been inserted through the anus and into the rectum. X-rays are then taken and the barium helps in visualizing the area of the intestine that has telescoped. The barium also serves as a treatment because it helps push the telescoping part of the intestine back into place.

Surgery. For those that may have a blockage, where stool is not able to pass through the intestine, surgery may be done right away. Surgery might also be done if the intussusception doesn’t respond to the other, less invasive treatments like air or barium enemas, or if there is a perforation (hole in the intestine).

During the surgery a portion of the bowel may need to be removed and then the two ends of the bowel are reconnected (a resection). Surgery may be done laparoscopically, with a few small incisions, or open, which is a larger incision. There will be a need to stay in the hospital for a few days after surgery, until the bowel wakes back up after surgery and the patient can eat normally again.

Prognosis

There is a risk of intussusception recurring soon after treatment. The rate of recurrence was estimated to be somewhere between 8% and 13% in one published review of 69 studies on intussusception in children.

Summary

Intussusception is more common in babies and children and more uncommon, and difficult to diagnose and treat, in adults. Children who have intermittent pain, demonstrated by crying and bringing legs up to the stomach, should be evaluated by a physician for a potential case of intussusception.

In most cases, the condition can be treated in children without surgery, and recurrence is not common. For adults, surgery might be needed more often. Most people recover well, with either treatment with an air or a liquid enema, or surgery, without the intussusception happening again.