Small Bowel and Colonic Intussusception

Intussusception is a condition in which one section of the bowel tunnels into an adjoining section, like a collapsible telescope. Intussusception can occur in the colon, the small bowel, or between the small bowel and colon. The result is a blocked small bowel or colon.

Intussusception is rare in adults. Causes include

• benign or malignant growths
• adhesions (scarlike tissue)
• surgical scars in the small bowel or colon
• motility disorders (problems with the movement of food through the digestive tract)
• long-term diarrhoea

Some cases of intussusception have been associated with viral infections and in patients living with AIDS. It can also occur without any known cause (idiopathic).

In infants and children, intussusception involving the small bowel alone, or the small bowel and the colon, is one of the most common causes of intestinal obstruction. Malrotation is a risk factor. Intussusception affects boys more often than girls, with most cases happening at 5 months and at 3 years of age. Most cases in children have no known cause, but viral infections or a growth in the small bowel or colon may trigger the condition. In the past, cases of intussusception appeared to be associated with a childhood vaccine for rotavirus, a common cause of gastroenteritis (intestinal infection). That vaccine is no longer given.

In adults with intussusception, symptoms can last a long time (chronic symptoms) or they can come and go (intermittent symptoms). The symptoms will depend on the location of the intussusception. They may include

• changes in bowel habits
• urgency—needing to have a bowel movement immediately
• rectal bleeding
• chronic or intermittent crampy abdominal pain
• pain in a specific area of the abdomen
• abdominal distention
• nausea and vomiting
• Children with intussusception may experience
• intermittent abdominal pain
• bowel movements that are mixed with blood and mucus
• abdominal distention or a lump in the abdomen
• vomiting bile
• diarrhoea
• ever
• dehydration
• ethargy
• shock (low blood pressure, increased heart rate requiring immediate attention)

If intussusception is not diagnosed promptly, especially in children, it can cause serious damage to the portion of the bowel that is unable to get its normal blood supply. A range of diagnostic tests may be required. X rays of the abdomen may suggest a bowel obstruction (blockage). Upper and lower GI series will locate the intussusception and show the telescoping. CT scans can also help with the diagnosis. When intussusception is suspected, an air or barium enema can often help correct the problem by pushing the telescoped section of bowel into its proper position.

Both adults and children may require surgery to straighten or remove the involved section of bowel. The outcome of this surgery depends on the stage of the intussusception at diagnosis and the underlying cause. With early treatment, the outcome is generally excellent. In some cases, usually in children, intussusception may be temporary and reverse on its own. If no underlying cause is found in these cases, no specific treatment is required.