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Intussusception
Telescoping bowel

Intussusception occurs when a segment of bowel telescopes (similar to closing of a telescope) into a segment just distal to it. It is the most common cause of intestinal (bowel) obstruction (blockage) between 3 months and 6 years of age. The ileocolic (small bowel into the colon) intussusception is the most common type although it may occur anywhere in the small bowel and colon.

Anatomy

  • The demarcation between the duodenum (1st part of small bowel) and the jejunum (2nd part of small bowel) is the ligament of Treitz (see Surgery of the Duodenum) (Figure 1)
  • The jejunum makes up about one third of the proximal small bowel
  • The ileum is the distal two thirds of the small bowel
  • The jejunum, ileum, and associated mesenteries (supporting and suspending structures) are attached to the back wall of the abdomen. They are completely covered with peritoneum (single layer of cells that line the surface of the abdomen and bowel)
  • The ileum joins the cecum (first part of the colon) in the right lower quadrant at the ileocecal valve near the appendix
  • The small bowel possesses an extensive lymphatic network that aids in the absorption of nutrients. It drains from the bowel wall into adjacent lymph vessels and lymph nodes and ultimately getting into larger lymphatics that finally empty into the left subclavian vein. The lymphatics of the small bowel play a major role in immune response (response to infection)

Pathology

  • The telescoping process is known as intussusception (Figure 2)
  • The leading proximal segment (intussusceptum) almost always telescopes into the distal segment (intussuscipens)
  • There may be a leading edge in the form of a polyp, inverted appendiceal stump, Meckel's diverticulum (See Surgery of the Jejunum and Ileum) or tumor
  • The leading edge gets caught up in the downstream peristalsis (wavelike action of the bowel wall that propels food) and is pulled into the distal bowel
  • In most cases the cause is unknown but viruses are thought to induce hyperplasia (increased size) of Peyer's patches (lymphoid tissue) in the end of the ileum

Figure 1 - Anatomy of the digestive tract showing the relationship of the small bowel (duodenum, jejunum and ileum) to the stomach and colon. © C. McKee

Figure 2 - Anatomy of a typical intussusception of ileum into the colon. The leading proximal, small bowel segment (intussusceptum) telescopes into the distal, colon segment (intussuscipens). © C. McKee

History and Exam

  • Typically, a happy child will have a sudden onset of severe colicky abdominal pain
  • The pain will occur in paroxysms (sudden attacks) and moments later the child may be happy and wanting to feed only to have another paroxysm
  • The pain increases as time passes because of the bowel wall changes as a result of the obstructive process
  • The bowel wall becomes compromised early and may become gangrenous and perforate (develop a hole in the wall) with constant severe pain
  • The child may pass bloody mucus through the rectum
  • On examination there is a tender distended abdomen often with a mass that can be felt in the upper abdomen that represents the intussusception
  • Rectal exam often shows a bloody mucus

Tests

  • X-ray of the abdomen may show the intussusception as an increase in density of the telescoped bowel
  • Barium enema (a barium solution that shows on X-ray is given as an enema) will show the tip of the obstructed intussusception
  • Ultrasound of the abdomen may show the intussusception
  • The white blood cell count is elevated

Indication for Surgery

  • The intussusception needs to be quickly reduced (straighten the bowel) either non-operatively or operatively because the bowel wall will lose its blood supply, become gangrenous and perforate
  • There is a 50% chance of non-operative reduction if the reduction is done within 24-48 hours
  • Non-operative reduction is accomplished under fluoroscopy utilizing a thin barium mixture or air alone with careful pressure control of the enema technique. The recurrence rate with this technique is about 10%
  • Operative reduction is carried out whenever non-operative reduction is unsuccessful or signs there are signs of peritoneal irritation. When signs of peritoneal irritation are present, the risk of bowel perforation with the pressure controlled enema is too high
  • Once signs of peritoneal irritation are present, prompt surgery is indicated

Surgery

  • Surgery is performed under general anesthesia with monitoring in a warmed operating room
  • A midline or transverse abdominal incision may be used. (Figure 3)
  • Careful inspection of the entire bowel is performed to determine if the bowel wall at the intussusception is alive
  • The intussusception is carefully reduced by gently pushing the leading portion of the intussusception back upstream to reduce the telescoping (Figure 4)

Figure 3 - Typical incisions for intussusception surgery. © C. McKee

Figure 4 - An ileum into colon intussusception reduced by gently pushing back the leading portion of the intussusception. © C. McKee
  • Careful examination of the reduced bowel is done to identify anything at the leading edge as the cause of the intussusception
  • The bowel may require fixation following reduction to prevent reoccurrence
  • Recurrence is very low following bowel resection
  • Bowel resection with anastomosis is carried out as follows:
    1. The bowel is inspected to determine if the bowel needs to be removed
    2. Any identified cause is removed. This may require removing the section of involved bowel with anastomosis (suturing the two cut ends together). If the bowel is nonviable (gangrenous) then resection of the intussusception with anastomosis without attempted reduction is performed (Figure 5 and 6)
    3. When the ileum is telescoped into the ascending colon, the involved bowel is removed back to normal bowel.
    4. The large bowel is cut straight across but the small bowel is cut at an angle so that the openings in the large and small bowel will be about the same (Figure 7)
    5. The two ends of the bowel are then anastomosed together with sutures. (Figure 8)

Figure 5 - Small bowel into small bowel intussusception with evidence of gangrene and showing the segment of small bowel being removed. © C. McKee

Figure 6 - Anastomosis between the two cut ends of the small bowel. © C. McKee
Figure 7 - Small bowel into colon intussusception. The colon is cut straight across and the small bowel cut at an angle so that the openings in the large and small bowel are similar. © C. McKeeFigure 8 - Anastomosis between the ileum and ascending colon. © C. McKee

Complications

  • The complications associated with any major operation should be anticipated:
  • Excessive bleeding
  • Respiratory distress
  • Hypothermia (low body temperature)
  • Low urine output
  • Infection
  • Bowel obstruction
  • Leak at any suture line of an anastomosis

Care After Surgery

  • The child is cared for in a Pediatric Intensive Care Unit
  • Breathing is monitored and the child may require ventilator support
  • Temperature and urine output is monitored
  • Intravenous (in the vein) fluids are given as necessary until the child can eat
  • A tube is placed through the nose into the stomach in order to decrease pressure in the bowel
  • Antibiotics are used as necessary

Follow Up Care

  • The children are usually hospitalized for approximately 5-7 days
  • At discharge, they are eating, drinking and having bowel movements
  • Follow up care is arranged with the surgeon and pediatrician