Intussusception

• Intussusception is the infolding (telescoping) of one segment of the intestine within another.
• Intussusception usually results in a blockage of the intestine.
• Intussusception occurs primarily in infants (boys more often than girls) but can also occur in adults and older children.
• The primary symptoms of intussusception include abdominal pain and vomiting.
• Early diagnosis and treatment of intussusception are essential to save the intestine and the patient.

Intussusception is the telescoping of one segment of intestine into another adjacent distal ("downstream") segment of the intestine. (The term "intussusception" is pronounced "in-tuh-suh-sep-shun" with the accent on the "in." It comes from the Latin "intus", within + "suscipere", to receive = to receive within). Common misspellings of intussusception include: intususception, intussuseption, intersusception.

Intussusception is the most common cause of intestinal obstruction in children between 3 months and 5 years of age. It is extremely rare in children under 3 months of age or in older children and adults.

During intussusception, a segment of bowel (intussusceptum) telescopes into a more distal segment (intussuscipiens), and drags the associated mesentery, vessels, and nerves with it. This results in compression of the veins, followed by swelling of the region leading to obstruction and a subsequent decrease in blood flow to the affected part of the intestine. Most cases affect the ileocolic region of the intestine (where the small intestine meets the large intestine).

The compression of blood vessels in the involved intestine reduces the supply of blood to the affected intestine. If the blood supply is greatly reduced, the involved intestine may swell, causing an obstruction, or even die (become gangrenous) and bleed. It also may rupture and lead to abdominal infection and shock.

Intussusception is an emergency and requires immediate attention.

Most cases of intussusception occur in children between 5 months and 1 year of age. Boys develop the condition two times more often than girls. Intussusception can also occur in adults and older children, although it is uncommon.

The causes of intussusception are not fully known. Most cases in young children are idiopathic, (meaning the cause is unknown), although some viral and bacterial infections of the intestine may possibly contribute to intussusception in infancy.

Intussusception is very rare in older children and adults. In this population, the causes are believed to be due to polyps or tumors, which are often referred to as the "lead point" of the intussusception.

Early diagnosis and treatment of intussusception is essential in order to prevent injury to the intestine and the associated sequelae, including surgical removal of the bowel, sepsis, and even death.

Most describe the symptoms of intussusception as a triad of colicky abdominal pain, bilious vomiting, and "currant jelly" stool.

The primary symptom of intussusception is described as intermittent crampy abdominal pain. This is often called "colicky pain." Intussusception in an infant usually starts with the infant suddenly crying very loudly, as if in great pain. The infant intermittently draws the knees up to the chest while crying. This reaction is caused by the abdominal pain which recurs frequently and increases in intensity and duration. These intermittent painful episodes are believed to be caused by the telescoping of the bowel and resultant compression of blood vessels and nerves.

In addition to the abdominal pain, most children will also have episodes of vomiting associated with the pain. This vomiting is usually not associated with eating and may be bilious (yellow-green colored)

Some affected individuals who do not seek early medical attention may pass "currant jelly stool". This is stool that is bloody and mucousy and may be a sign that the affected bowel has lost its blood supply and that the bowel may be necrotic (non-viable).

As the condition progresses, the infant becomes may become weaker and develop additional symptoms, including those associated with shock, such as paleness, lethargy, and even fever, though these are not an integral part of the associated "triad."

Thankfully, most cases are diagnosed early.

The history of abdominal pain and vomiting as described above, may suggest the diagnosis of intussusception. Additionally, the examining doctor may feel an abdominal "sausage-shaped" mass (the intussusception itself) or upon auscultation with a stethoscope, may hear diminished or absent bowel sounds. Lab tests are usually not helpful, although plain abdominal X-rays can reveal signs of an intestinal obstruction, including air-fluid levels, decreased gas, and unexplained masses, usually seen in the right lower quadrant of the abdomen. Ultrasound and CT scans are generally not required to make the diagnosis.

A barium, water-soluble contrast or air enema is considered both diagnostic and therapeutic in the management of intussusception. This radiologic procedure involves the introduction of the contrast into the lower intestine. If an intussusception is present, it will be seen during the imaging. Often just the introduction of the contrast will reduce the telescoped bowel to its normal position and shape. In these cases, there is a high risk of for re-intussusception in the first 24 hours following the enema, though, less commonly, recurrence may be seen several days and even months later.

The treatment of intussusception may or may not require surgery. In some cases, the intestinal obstruction can be reversed with an enema. The enema carries a risk of intestinal rupture and cannot be done if the bowel has already perforated. The procedure also requires the availability of a surgeon, in case the patient's bowel ruptures or the intussusception cannot be reduced.

If the intestinal obstruction cannot be reversed by an enema, surgery is necessary to reverse the intussusception and relieve the obstruction. If a portion of the intestine has become gangrenous, it must be removed. After surgery, intravenous feeding and fluids are continued until normal bowel movements resume. Because of the risk of recurrence, patients who are successfully reduced by enema usually are admitted for observation during the first 24 hours post procedure, and have no ill effects. Recently, research has suggested that a select population of the children may be observed for shorter periods of time (6 hours) after undergoing reduction of the intussusception by enema, but currently, most patients stay the full 24 hours.

The outlook for intussusception is usually good with early diagnosis and treatment. Early detection and treatment are paramount.