Intussusception is the sliding of one part of the intestine into another.

Intussusception is caused by part of the intestine being pulled inward into itself. This can block the passage of food through the intestine. If the blood supply is cut off, the segment of intestine pulled inside can die.

The pressure created by the walls of the intestine pressing together causes:

• Decreased blood flow
• Irritation
• Swelling

The intestine can die, and the patient can have significant bleeding. If a hole occurs, infection, shock, and dehydration can take place very rapidly.

The cause of intussusception is not known, although viral infections may be responsible in some cases. Sometimes a lymph node, polyp, or tumor can trigger the problem. The older the child, the more likely such a trigger will be found.

Intussusception can affect both children and adults, although most cases occur in children ages 6 months - 2 years. It affects boys four times as often as girls.

The first sign of intussusception is usually sudden, loud crying caused by abdominal pain. The pain is colicky and not continuous (intermittent), but it comes back often, increasing in both intensity and duration.

An infant with severe abdominal pain may draw the knees to the chest while crying.

Other symptoms include:

• Bloody, mucus-like bowel movement, sometimes called a "currant jelly" stool
• Fever
• Shock (pale color, lethargy, sweating)
• Stool mixed with blood and mucus
• Vomiting

Your doctor will perform a thorough examination, which may reveal a mass in the abdomen. There may also be signs of dehydration or shock.

Tests may include:

• Abdominal x-ray
• Air or contrast enema

The child will first be stabilized. A tube will be passed into the stomach through the nose (nasogastric tube). An intravenous (IV) line will be placed in the arm and fluids will be given to prevent dehydration.

In some cases, the bowel obstruction can be treated with an air or contrast enema performed by a skilled radiologist. There is a risk of bowel tearing (perforation) with this procedure, and it is not used if the bowel has already developed a hole.

If these treatments are unsuccessful, the child will need surgery. The bowel tissue can usually be saved, but any dead tissue will be removed.

Intravenous feeding and fluids will be continued until the child has a normal bowel movement.

The outcome is good with early treatment. There is a risk the condition will come back.

A hole (perforation) is a serious complication due to risk of infection. If not treated, intussusception is almost always fatal for infants and young children.

Intussusception is an EMERGENCY. Call your health care provider immediately, then call 911 or go immediately to the emergency room.

Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Kliegman: Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007.