Intussusception is a condition in which part of the intestine folds into itself, much like a collapsible telescope. Usually, the last part of the small intestine, called the ileum, folds into the first part of large intestine, called the cecum.

In the United States, about 35 to 40 of every 100,000 babies younger than age 1 is hospitalized for intussusception. Intussusception is the most common cause of intestinal obstruction in babies and young children.

What is the lower GI tract?

The lower gastrointestinal (GI) tract is the last part of the digestive tract. The lower GI tract consists of the large intestine and the anus.

The large intestine absorbs water and changes the waste products of the digestive process from liquid into formed stool. The large intestine includes

• the appendix, a finger-shaped pouch attached to the cecum
• the cecum, the first part of the large intestine, which is connected to the end of the small intestine
• the colon, which has four sections: the ascending colon, the transverse colon, the descending colon, and the sigmoid colon
• the rectum, the lower end of the large intestine leading to the anus

The anus is a 1-inch opening at the end of your digestive tract through which stool leaves your body. The anus includes the sphincter muscles—muscles that open and close and allow you to control bowel movements.

What are anatomic problems of the lower GI tract?

Anatomic problems of the lower GI tract are problems related to the structure of the lower GI tract. The parts of the lower GI tract may be in the wrong place, may not be shaped normally, or may not connect normally to other parts of the body.

Some anatomic problems of the lower GI tract arise when the lower GI tract does not develop normally before birth. These are called birth defects and include

• anorectal malformations
• colonic atresia and stenosis
• malrotation

Other anatomic problems, which might be present at birth or develop later, include

• intussusception
• colonic and anorectal fistulas
• rectal prolapse
• colonic volvulus

Babies and young children are more likely than adults to get intussusception. Intussusception is most common in babies younger than age 1, and about 90 percent of cases occur in children younger than age 3.

Intussusception is rare in adults. Only about 5 percent of cases of intussusception occur in adults.

Intussusception is more common in boys than in girls.

Children

In most cases of intussusception in babies and young children, doctors cannot find a cause. Research suggests that infections with viruses or bacteria may increase the chance of intussusception.

Doctors can find a cause in only 2 to 12 percent of cases of intussusception in children. These causes include

• abnormal growths in the intestines, such as benign or cancerous tumors, polyps, or cysts
• birth defects in the digestive tract, such as malrotation and Meckel’s diverticulum
• diseases and disorders such as cystic fibrosis, IgA vasculitis, and hemophilia
• surgery

Adults

In adults, doctors can find the cause of intussusception in about 90 percent of cases.Causes of intussusception in adults include

• abnormal growths in the intestines, such as benign and cancerous tumors and polyps
• abdominal adhesions that form after surgery
• diseases such as cystic fibrosis, celiac disease, and Crohn’s disease

Anyone with signs or symptoms of intussusception or its complications should get medical help right away.

The signs and symptoms of intussusception in babies and children may include

• severe colicky or crampy pain in the abdomen
• crying and not able to be comforted
• drawing their knees up to their chest
• lethargy, or lack of energy
• vomiting
• stool mixed with blood and mucus, called currant jelly stool

Symptoms of intussusception in adults may include

• pain in the abdomen
• nausea
• vomiting
• bleeding from the rectum or blood in the stool
• constipation
• bloating

Signs and symptoms of complications of intussusception may include

• signs of dehydration, such as thirst, urinating less than usual, and feeling tired
• signs of infection, such as fever
• signs of shock, such as confusion or unconsciousness, a fast heart rate, pale skin, and sweating

To diagnose intussusception, doctors will ask about symptoms and medical history, perform a physical exam, and order imaging tests.

Physical exam

During a physical exam, the doctor may

• check for bloating of the abdomen
• check for a lump or mass in the abdomen
• press or tap on the abdomen to check for tenderness or pain
• use a stethoscope to listen to sounds in the abdomen
• check for signs of complications, such as dehydration or shock

Imaging tests

Doctors may use the following tests to diagnose intussusception

• x-rays, which use a small amount of radiation to create pictures of the inside of the body
• ultrasound, which uses sound waves to create an image of organs
• lower GI series, which uses x-rays and a chalky liquid called barium to view the large intestine
• computed tomography (CT), more commonly used in adults, which uses a combination of x-rays and computer technology to create images

In babies and children, doctors most often treat intussusception by performing an enema procedure that is similar to a lower GI series. A doctor inserts a tube through the anus and, with x-ray guidance, fills the large intestine with air, barium, or another substance to push the telescoped intestine back to its normal position.

A doctor may need to perform surgery to treat intussusception if the enema procedure does not work. A doctor may also perform surgery if the cause or complications of intussusception need treatment.

In adults, doctors most often treat intussusception with surgery.

Without treatment, intussusception can lead to life-threatening complications, such as

• intestinal obstruction
• dehydration
• lack of blood flow to the blocked part of the intestine and death of the blood-starved tissues
• a perforation, or hole, in the wall of the intestine
• peritonitis, an infection of the lining of the abdominal cavity
• sepsis, a serious illness that occurs when the body has an overwhelming immune system response to an infection
• shock