Diagnostic and therapeutic enema.

Air contrast or water-soluble contrast (e.g. Triombraste/Verografin) enema is the “gold-standard” diagnostic study for infants with suspected intussuception. It is both diagnostic and therapeutic in identifying and reducing intussusception. The diagnostic enema is therapeutic in 80-90% of patients.

Hydrostatic enema or pneumatic enema is used to confirm the diagnosis and to reduce the intussusception.

Hydrostatic reduction is contraindicated if the child has signs of peritonitis.

In North America and Western Europe some pediatric surgeons have been using barium as contrast for hydrostatic enema.

A lubricated straight catheter is placed into the rectum and secured by taping the buttocks together tightly. While many radiologists prefer a balloon-tipped catheter, laceration or perforation of the rectum is a risk with balloon inflation.

A manometer and blood pressure cuff are connected to the catheter, and air is insufflated slowly to a pressure of 70-80 mm Hg (maximum 120 mm Hg) and followed fluoroscopically as it percolates proximally through the colon. The column of air stops at the intussusception, and a plain radiograph is taken.

Each attempt should persist until reduction of the intussusception fails to progress for a period of 3-5 minutes. A maximum of three attempts should be made.

If no intussusception exists or if the reduction is successful, air (or other contrast) is observed to rapidly pass into the small bowel. Reflux of air into the terminal ileum, seen flouroscopically, signifies reduction of the intussusception.

Ultrasonography is advocated to aid in the diagnosis and assist with hydrostatic reduction of intussusception. Hence, ultrasonographically guided hydrostatic reduction for childhood ileocolic intussusception is preferred because it is safe, accurate, has a higher success rate, and can avoid radiation exposure risk.

If the intussusception is successfully reduced, an oral diet is resumed on the next morning.

If the intussusception cannot be completely reduced, operative intervention is indicated.

Differentiation

Disorders characterized by bowel obstruction, colicky abdominal pain, blood in the stool, an intra-abdominal mass, or a combination of these should be considered in the differential diagnosis of intussusception. These include gastroenteritis, appendicitis, Meckel diverticulum, malrotation with midgut volvulus, rectal mucosal prolapse or incarcerated hernia.

Treatment

Conservative treatment:

The use of contrast enemas allows direct visualization of the reduction under fluoroscopic control and is reported to be successful in 80% to 90% of cases (in some reports 65-70%).

Conservative treatment is contraindicated if the:

§ Recurrent intussusception

§ Patient’s age > 1 year or < 3 month

§ Appearance time of first symptoms more than 18 hours

§ X-ray evidence of a ileo-ileal (small intestine) intussusception

§ GI bleeding

Surgical treatment:

Surgery is indicated in children with:

§ Failed enema reduction

§ Peritonitis

§ Clinical evidence of dead bowel

§ Septicemia

§ Evidence of an anatomic/pathologic lead point

Preoperative details: Preoperatively, IV crystalloid resuscitation is begun (10 mL/kg x 2, plus 1.5 x maintenance fluid). A nasogastric tube is placed. Broad-spectrum IV antibiotics are administered. Body temperature must be preserved in the operating room. A type and screen of the patient's blood should be obtained. As with any patient with a bowel obstruction, careful induction of anesthesia should take place because of the risk of regurgitation and aspiration.

Surgical exploration for intussusception is performed through a right lower quadrant transverse incision. After inspection for signs of perforation, the intussusception is identified and delivered into the wound. First, an attempt is made at manual reduction by retrograde milking of the intussusceptum (retrograde pressure is applied by squeezing the intussusceptum within the intussucipiens in a proximal direction). Although gentle pulling may aid in reduction, avoid vigorous pulling a part of the intussuscepted segment of bowel. Following successful reduction, it is important to assess bowel viability and search for anatomic lead points.

If manual reduction is unsuccessful, if a mass or pathologic lead point is present, or if perforation has occurred, segmental bowel resection is necessary. After resection, a primary anastomosis may be performed. Often after successful manual reduction, the involved segment of bowel appears edematous, hyperemic, or ischemic. These findings do not necessarily mandate resection. An incidental appendectomy is often performed, particularly if a right lower quadrant incision was made for access to the abdomen, as it may be presumed that the patient has had an appendectomy.

Local or segmental resection is indicated if:

o the intussusception cannot be reduced,

o the segment of bowel appears infarcted or nonviable, or

o a lead point is identified.

Primary anastomosis can usually be performed with minimal morbidity.

Complications

Intussusception cuts off the blood supply to the bowel. If this is not treated quickly, it can lead to bowel gangrene. Gangrene can cause tissue in the intestinal wall to die. This may lead to:

· Perforation of the intestinal wall

· Peritonitis (inflammation of the lining of the abdominal cavity) and infection

· If not treated quickly, peritonitis can lead to death.

Perforation with Pressure Reduction

In a large international survey, the cumulative incidence of perforation complicating hydrostatic reduction was 0,18%. It remains controversial whether pneumatic reduction is safer than hydrostatic reduction. The incidence of perforation has been higher with pneumatic reduction and varies between 1% and 2,8%. With increasing experience in pneumatic reduction, the incidence of perforation is decreasing. A more intense inflammatory reaction occurs with the peritonitis complicating a perforation with barium than that seen with water-soluble contrast or air contrast enemas. The mixture of barium and feces can lead to a prolonged septic course. Infants younger than 6 months of age and children with symptoms for longer than 36 hours, or with evidence of bowel obstruction, are at greater risk for having gangrenous bowel complicating their intussusception. They are consequently at greater risk for perforation.

Outcomes

The recurrence rate of intussusception after successful reduction (whether hydrostatic or surgical) is about 5-7%. Recurrence may be slightly lower with reduction using air insufflation. The mortality rate of intussusception is less than 1%. Mortality increases with delay in diagnosis, inadequate fluid resuscitation, perforation, and surgical complications.

Postoperative intussusception

In series from large children's hospitals, postoperative intussusception accounts for 1,5% to 6% of all cases of intussusception. The incidence of postoperative intussusception after laparotomy is 0,08% to 0,5%, but this process may complicate cardiac, thoracic, and orthopedic procedures. The diagnosis of postoperative intussusception is infrequently established by contrast enema, and a contrast meal with small bowel films may identify the obstruction. The intussusception is most frequently located in the small intestine.

The cause of postoperative intussusception is believed to be altered peristalsis due to prolonged or excessive manipulation of the bowel, bruising of the intestine, anesthetic agents, or other neurogenic factors. The higher incidence of postoperative intussusception seen in children who have known dysmotility suggests that abnormal propulsion of the intestine may be an important factor. Lead points from anastomotic suture lines are rarely found.

Nonischemic (chronic) intussusception

About 15% of cases of intussusception in children may be described as subacute (symptoms of 4 to 14 days) or chronic (symptoms greater than 14 days) (by Keith T. Oldham, 2005). Patients with nonischemic intussusception present with recurrent mild to moderate abdominal discomfort and other nonspecific GI complaints, including vomiting, diarrhea, rectal bleeding, and failure to thrive. Ischemic compromise of the intussusceptum is rarely found, and abdominal masses are infrequently appreciated in this group.

This nonspecific presentation and frequently normal abdominal examination lead to the common but erroneous diagnosis of gastroenteritis. The presence of a pink mucoid semiloose bowel movement may lead the examiner to suspect the diagnosis of chronic intussusception. Nonischemic intussusception should be included in the differential diagnosis of prolonged cases of vomiting and diarrhea, particularly if stools are positive for occult blood. Awareness of this entity will lead to correct diagnosis, and appropriate therapy can be initiated.

Neonatal intussusception

Neonatal intussusception, with symptoms occurring in the first 30 days of life, is rare. 60% to 75% of newborn infants with intussusception are found to have surgical lead points. Once the diagnosis of neonatal intussusception is confirmed, surgery is the preferred treatment option. There is a high incidence of surgical lead points, a low rate of successful enema reduction in small infants, and a greater risk of bowel perforation in infants younger than 6 months of age undergoing pressure reduction. Repeated attempts at hydrostatic or pneumatic reduction are not indicated once the diagnosis is established.