Intussusception

• It is the most common cause of intestinal obstruction between 5 months and 3 years of age and the most common abdominal emergency in children younger than 2 years.
• Intussusception is derived from two Latin words: intus (within) and suscipere (to receive).
• Intussusception occurs when a portion of the alimentary tract is telescoped into an adjacent section.

• Incidence varies from 1 to 4 per 1,000 live births.
• Male:Female ratio is 3:1.
• Sixty percent of patients are younger than 1 year of age, and 80% of the cases occur before age 24 months.
• It is rare in neonates.

• Introduction of new feeds
• Preceding upper respiratory tract infection
• Preceding gastrointestinal infection
• Rotavirus vaccine (Rotashield - no longer in use)
• Pathologic lead point (e.g., Meckel diverticulum, intestinal polyp, etc.)

• IDIOPATHIC
  • Majority of cases (95%)
  • No PATHOLOGIC lead point
  • Peyer's patches are usually located in the antimesenteric area of the bowel wall
  • In the distal ileum, it involves the entire circumference of the bowel
  • Malnourished children are at lower risk because of less prominent intestinal lymphoid tissue
  • Incidence is higher in infants fed on cow milk than soy milk formula
• Pathologic lead point (PLP)
  • Incidence increases with age
  • 5% in the 1st year, 44% in the 5th year, 60% in the 5-14th year
  • Most common PLP - Meckel diverticulum, intestinal polyp
  • Others - benign tumor, malignant tumor, celiac disease, cystic fibrosis, Familial Adenomatous Polyposis
• Post-operative
  • Manifests as small bowel obstruction
  • 3rd most common cause of intussusception
  • Usually after prolonged laparotomy due to significant bowel handling
• Anatomic
  • Ileocolic (85%)
  • Ileoileocolic (10%)
  • Appendicocolic, cecocolic, colocolic (2.5%)
  • Jejunoileal, ileoileal (2.5%)
  • Around indwelling tube

• Three layers of the intestinal wall are involved
• The inner and middle layers are the invaginated bowel (intussusceptum)
• The outer layer is the recipient of the invaginated bowel (intussuscipiens)

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• In enteroenteral intussusception, there is an imbalance in the longitudinal forces along the intestinal wall
• This imbalance can be caused by a mass acting as a lead point or by a disorganized pattern of peristalsis (e.g., an ileus in the postoperative period)
• As a result of this imbalance, an area of the intestine invaginates into the lumen of adjacent bowel
• The invaginating portion of the intestine (i.e., the intussusceptum) completely “telescopes” into the receiving portion of the intestine (i.e., the intussuscipiens)
• This process continues and more proximal areas follow, allowing the intussusceptum to proceed along the lumen of the intussuscipiens
• The mesentery of the intussusceptum is invaginated with the intestine, leading to the classic pathophysiologic process of any bowel obstruction
• Early in this process, lymphatic return is impeded; then, with increased pressure within the wall of the intussusceptum, venous drainage is impaired
• If the obstructive process continues, the pressure reaches a point at which arterial inflow is inhibited, and infarction ensues
• The intestinal mucosa is extremely sensitive to ischemia because it is farthest away from the arterial supply
• Ischemic mucosa sloughs off, leading to the heme-positive stools and subsequently to the classic "currant jelly stool" (a mixture of sloughed mucosa, blood, and mucus)
• If untreated, transmural gangrene and perforation of the leading edge of the intussusceptum occur

• Bowel perforation
• Wound infection
• Sepsis
• Intestinal hemorrhage
• Necrosis
• Recurrence

• General health promotion
  • Educate mothers on hygienic practices (proper handwashing)
  • Exclusive breastfeeding
• Specific protection
  • Early diagnosis and prompt treatment
  • High index of suspicion by the physicians
• Limitation of disability
• Rehabilitation

• Untreated intussusception in infants is usually fatal
• The chances of recovery are directly related to the duration of intussusception before reduction
• Most infants recover if the intussusception is reduced in the first 24 hours, but the mortality rate rises rapidly after this time, especially after the second day
• The recurrence rate after reduction of intussusception is approximately 10%, and after surgical reduction it is 2-5%
• None has recurred after surgical resection. Most recurrences occur within 72 hours of reduction
• Corticosteroids may reduce the frequency of recurrent intussusception
• A single recurrence of intussusception can usually be reduced radiologically
• Laparoscopic reduction carries a very low mortality
• Repeated reducible episodes caused by lymphonodular hyperplasia may respond to treatment of identifiable food allergies

Poor Prognostic Factors

• Delayed presentation beyond 48 hours from the onset of symptoms
• Severe respiratory distress at presentation
• Temperature > 38.5 degrees Celsius at admission
• Severe acidosis
• Severe dehydration
• Delay in surgical intervention beyond 48 hours

• Intussusception often presents with a wide range of non-specific symptoms
• The 4 classic symptoms of pain, emesis, bloody stool +/- mass are together present in < 25% of children
• Success rate of non-operative reduction is > 90%
• Duration of complaint is the key for successful reduction