Intussusception

What is intussusception?

Intussusception is a condition in which one part of the intestine slides into an adjacent part, much like the segments of a collapsible telescope folding into each other. Doctors sometimes describe this as the bowel “telescoping.” When this happens, the folded section of intestine can block the passage of food and fluid. It can also squeeze the blood vessels that supply that part of the bowel, cutting off blood flow. If the blood supply is interrupted for too long, the affected tissue can become swollen, damaged, or even die, which is why intussusception is treated as a medical emergency in most cases.

Understanding what is intussusception starts with knowing who it affects. It is the most common cause of intestinal obstruction (a blockage of the bowel) in infants and young children, most often occurring between about 3 months and 3 years of age. Boys are affected somewhat more often than girls. Although it is far less common, intussusception can also occur in older children and adults. In adults, it usually has a different underlying cause than in young children and is often discovered while investigating other abdominal problems.

The most frequent location is where the small intestine (the ileum) meets the large intestine (the colon). This is called ileocolic intussusception. Other patterns exist, such as small bowel folding into small bowel, but the ileocolic type accounts for the majority of childhood cases.

With prompt recognition and treatment, most children recover fully. Delays, on the other hand, increase the risk of serious complications such as bowel perforation (a hole in the intestinal wall) and infection of the abdominal cavity. That is why awareness of the warning signs matters so much for parents and caregivers.

Symptoms of intussusception

Intussusception symptoms can be dramatic, but they can also be subtle at first, especially in very young infants who cannot describe what they feel. The picture also changes as the condition progresses, so it helps to know both the early and later signs.

Common intussusception symptoms in infants and young children include:

• Sudden episodes of severe abdominal pain: a previously well child may suddenly cry intensely, often drawing the knees up toward the chest. The pain typically comes in waves, with the child seeming calm or even sleepy between episodes.
• Vomiting: this may begin as ordinary vomiting and can later become green or yellow-green (bilious), which suggests the bowel is blocked.
• Blood and mucus in the stool: a classic but late finding is stool that looks like red currant jelly, a mixture of blood and mucus. Not every child develops this, and its absence does not rule out intussusception.
• A lump in the abdomen: a doctor may feel a sausage-shaped mass, often in the upper right part of the belly.
• Lethargy or unusual drowsiness: some infants become strikingly floppy, pale, or hard to wake. Occasionally lethargy is the main or only sign, which can be confusing because it may look like a neurological problem rather than a bowel problem.
• Refusing feeds, irritability, or a swollen belly.

In the early stage, the pattern of on-and-off crying spells with quiet intervals is typical. As hours pass and the bowel becomes more swollen and its blood supply more compromised, the child may become persistently unwell: continuously distressed or unusually limp, with a distended (swollen) abdomen, ongoing vomiting, fever, or signs of dehydration such as fewer wet diapers. Bloody stools tend to appear later in the course and suggest that the bowel lining is already injured.

In older children and adults, symptoms are often less dramatic and more chronic. Adults may experience recurring crampy abdominal pain, nausea, vomiting, changes in bowel habits, or intermittent partial blockages that come and go over weeks or months. Because these complaints overlap with many other digestive conditions, adult intussusception is frequently identified on imaging performed for another reason.

It is worth repeating that not every child shows the full “classic” set of symptoms. Many children have only one or two of them. Any combination of severe intermittent abdominal pain, vomiting, and blood in the stool in an infant or toddler should prompt urgent medical assessment.

Causes and risk factors

In most infants and toddlers, no single definite cause is found. These cases are called idiopathic, which simply means the cause is unknown. However, researchers believe that in many young children the trigger is enlargement of lymphoid tissue in the wall of the intestine. Lymphoid tissue is part of the immune system, and patches of it (called Peyer’s patches) sit in the last part of the small intestine. When a child has a viral infection—such as a common stomach bug or respiratory virus—this tissue can swell. The swollen patch may then act as a “lead point,” a spot that the normal squeezing movements of the bowel catch onto and drag forward, pulling one segment of intestine into the next. This may help explain why intussusception in children often follows a recent viral illness and why cases can cluster in certain seasons.

Recognized intussusception causes and risk factors include:

• Age: the condition is most common between roughly 3 months and 3 years of age.
• Sex: boys are affected more often than girls.
• Recent viral infection: gastroenteritis (stomach flu) or upper respiratory infections may precede an episode.
• A structural lead point: in a minority of children—and more commonly in older children and adults—a physical abnormality drags the bowel inward. Examples include a Meckel’s diverticulum (a small pouch in the intestinal wall present from birth), polyps (growths on the bowel lining), cysts, or tumors.
• Certain medical conditions: disorders such as Henoch-Schönlein purpura (an inflammation of small blood vessels that can thicken the bowel wall), cystic fibrosis, and celiac disease have been associated with intussusception.
• Prior abdominal surgery: scar tissue or altered bowel anatomy can occasionally contribute, particularly in adults.
• A previous episode: children who have had intussusception once have a somewhat higher chance of it happening again.

In adults, intussusception is uncommon, and when it occurs a lead point is found in many cases. Because that lead point can sometimes be a tumor, adult intussusception generally prompts a more thorough search for an underlying cause than childhood cases do. This is one of the main ways adult and pediatric intussusception differ.

Importantly, intussusception is not caused by anything a parent did or failed to do. It cannot be reliably prevented, and it is not contagious.

Diagnosis

Intussusception diagnosis begins with a careful history and physical examination. The doctor will ask about the pattern of pain, vomiting, stool changes, recent illnesses, and how the child has been behaving. On examination, the doctor may feel a sausage-shaped mass in the abdomen and will check for signs of dehydration, a swollen or tender belly, and blood on rectal examination. Because the symptoms overlap with other causes of abdominal pain, imaging is almost always needed to confirm the condition.

• Abdominal ultrasound: this is the preferred first test in children. Ultrasound uses sound waves, involves no radiation, and is very accurate in experienced hands. The telescoped bowel produces characteristic patterns on the screen, often described as a “target” or “doughnut” sign when viewed in cross-section. Ultrasound can also give clues about blood flow to the affected segment.
• Abdominal X-ray: a plain X-ray may show signs of bowel obstruction or, in severe cases, free air suggesting a perforation. A normal X-ray does not rule out intussusception, so it is usually combined with ultrasound.
• Contrast or air enema: in this test, air or a liquid contrast material is gently introduced into the rectum while images are taken. It can confirm the diagnosis and—very usefully—often treats the condition at the same time (see the treatment section below).
• CT scan: computed tomography is used more often in adults, where it can both identify the intussusception and help find a lead point such as a polyp or tumor. In children, doctors generally try to avoid CT because of the radiation involved, unless there is a specific reason.
• Blood tests: these do not diagnose intussusception directly, but they help assess dehydration, infection, and overall condition before treatment.

Doctors also consider other conditions that can look similar, such as gastroenteritis, appendicitis, malrotation with volvulus (a twisting of the bowel), or constipation. Because an intussusception can occasionally reduce (slide back out) on its own before imaging, a child with a convincing story but a normal first scan may be observed or rescanned if symptoms return.

Treatment options for intussusception

Intussusception treatment is urgent in nearly all childhood cases. The goals are to relieve the blockage, restore blood flow to the affected bowel, and prevent or manage complications. Treatment usually happens in a hospital, and in children it is coordinated by pediatric emergency, radiology, and surgical teams; at Acibadem, for example, childhood cases are managed through the pediatrics department together with pediatric surgery.

Initial stabilization. Before any procedure, the care team typically gives intravenous (IV) fluids to correct dehydration, keeps the child from eating or drinking (in case surgery is needed), and may pass a thin tube through the nose into the stomach to relieve pressure if the bowel is blocked. Pain relief is provided as needed.

Enema reduction (non-surgical treatment). For most children whose condition is stable and whose bowel has not perforated, the first-line treatment is an air enema or a liquid contrast (or saline) enema performed by a radiologist, often with ultrasound or X-ray guidance. The gentle pressure of the air or fluid pushes the telescoped segment back into its normal position. This approach succeeds in a large proportion of children and avoids surgery altogether. It is not painless, but it is quick, and children are monitored closely during and after the procedure. The main risk is perforation of the bowel, which is uncommon but is the reason the procedure is done in a hospital with surgical backup available. If the first attempt does not fully reduce the intussusception and the child remains stable, doctors may sometimes repeat the attempt after a short interval.

Surgery. An operation is needed when an enema cannot be performed safely (for example, if the bowel has perforated or the child is very unwell), when enema reduction fails, or when a lead point such as a polyp or Meckel’s diverticulum is suspected. During surgery—performed either through a traditional incision or, in suitable cases, laparoscopically (keyhole surgery with small incisions and a camera)—the surgeon gently squeezes the telescoped bowel back into place. If a segment of intestine has lost its blood supply and is no longer healthy, that segment is removed and the healthy ends are joined together. Any lead point found is also removed. In adults, surgery is often the preferred treatment from the outset, both to relieve the obstruction and to remove and examine any underlying lesion.

Watchful waiting. True watchful waiting is appropriate only in limited situations. Small intussusceptions of the small bowel, sometimes found incidentally on scans in children or adults with few or no symptoms, may resolve on their own, and doctors may choose careful observation with repeat imaging. A symptomatic child with a confirmed ileocolic intussusception, by contrast, needs active treatment rather than waiting.

Medication. There is no medicine that reverses intussusception itself. Medications play a supporting role: IV fluids, pain relief, anti-nausea medicines, and antibiotics when perforation or infection is present or when surgery is planned.

After treatment. Children are usually observed in the hospital afterward, because intussusception can recur, most often within the first days after reduction. Recurrence happens in a minority of children and is usually treated the same way as the first episode. After successful enema reduction, feeding is typically restarted gradually once the child is comfortable. Recovery after surgery takes longer, particularly if a segment of bowel was removed, and the team will advise on feeding, wound care, and activity.

Living with intussusception and outlook

For most children, intussusception is a single frightening episode rather than a lifelong condition. When it is diagnosed and treated promptly, the outlook is generally very good: the bowel returns to normal function, and long-term digestive problems are uncommon. Children who needed surgery, including those who had a portion of bowel removed, also usually recover well, although their hospital stay and recovery period are longer.

The main factor that worsens outcomes is delay. The longer the bowel’s blood supply is compromised, the higher the risk of tissue death, perforation, peritonitis (infection of the abdominal cavity), and sepsis (a dangerous body-wide response to infection). These complications are serious and, if untreated, intussusception can be life-threatening. This is why parents who have been through one episode are usually advised to seek care quickly if similar symptoms ever return.

Recurrence is possible but affects only a minority of children. Most recurrences happen soon after the initial treatment, which is one reason for the short period of hospital observation. Repeated recurrences may prompt doctors to look harder for a lead point.

Adults who have had intussusception related to a lead point will usually have follow-up focused on the underlying cause—for example, surveillance after removal of a polyp or tumor. Your doctor will tailor follow-up to your individual situation; no single schedule fits everyone.

Day to day, no special long-term diet or activity restriction is typically needed once recovery is complete, unless the care team advises otherwise because of surgery or an underlying condition.

Frequently asked questions

What is intussusception in simple terms?

Intussusception means one part of the intestine has slipped inside the part next to it, the way a telescope folds together. The folded section can block the bowel and pinch off its blood supply. It is most common in babies and toddlers and usually needs urgent hospital treatment, although in most cases it can be corrected without a major operation.

How serious is intussusception?

It is considered a medical emergency in children because a blocked, blood-starved segment of bowel can be damaged within hours. Treated promptly, most children recover completely. Left untreated, it can lead to perforation of the bowel, serious infection, and, rarely, death. The seriousness depends largely on how quickly care is received, so early evaluation matters more than almost anything else.

Can intussusception heal on its own?

Occasionally, especially with small intussusceptions of the small bowel found incidentally on scans, the bowel slides back into place by itself. However, a child with symptoms of a confirmed ileocolic intussusception should not wait for this to happen. Doctors treat symptomatic cases actively, most often with an air or contrast enema, because the risk of complications rises with time.

What are the first signs of intussusception in a baby?

The earliest sign is often sudden, severe crying spells in which the baby pulls the legs up toward the belly, with calm or drowsy periods in between. Vomiting is also common early on. Blood and mucus in the diaper—sometimes described as looking like red currant jelly—tends to appear later. Some infants show mainly unusual sleepiness or floppiness, so a strikingly lethargic baby also deserves urgent assessment.

How is intussusception diagnosed?

In children, doctors usually confirm intussusception diagnosis with an abdominal ultrasound, which shows a characteristic “target” or “doughnut” pattern where the bowel is telescoped. A plain X-ray may be added to look for obstruction or perforation. In adults, a CT scan is used more often, partly to search for an underlying lead point. Blood tests help assess the patient’s overall condition before treatment.

Does intussusception always require surgery?

No. In children, the majority of cases can be treated without surgery, using an air or liquid enema that gently pushes the bowel back into position under imaging guidance. Surgery is reserved for situations where the enema fails or cannot be done safely, where the bowel has perforated or lost its blood supply, or where a structural lead point needs to be removed. In adults, surgery is more commonly the first choice.

Can intussusception come back after treatment?

Yes, in a minority of children it recurs, most often within the first few days after successful reduction, which is why a short period of hospital observation is standard. A recurrence is usually treated the same way as the first episode. If intussusception keeps returning, doctors may investigate more thoroughly for a lead point such as a polyp or diverticulum.

When to see a doctor

Because intussusception can worsen quickly, do not wait to see whether symptoms pass on their own. Seek emergency medical care right away if an infant or child has any of the following:

• Sudden episodes of intense crying or abdominal pain, especially with the knees drawn up to the chest, coming in waves.
• Vomiting that persists, particularly if the vomit turns green or yellow-green.
• Blood or mucus in the stool, including stool resembling red currant jelly.
• Unusual drowsiness, floppiness, or paleness, or a child who is difficult to wake.
• A swollen, hard, or very tender belly.
• Signs of dehydration, such as far fewer wet diapers, dry mouth, or no tears when crying.
• Fever combined with any of the above.

Adults should seek prompt medical attention for severe or worsening abdominal pain, persistent vomiting, blood in the stool, or an inability to pass stool or gas, as these can signal a bowel obstruction from intussusception or another cause. If a child has already been treated for intussusception and similar symptoms return—even weeks later—have them evaluated urgently, since recurrence is possible. When in doubt, it is always safer to have symptoms checked early than to wait.