Intussusception occurs when 1 portion of proximal intestine (intussusceptum) telescopes into a more distal portion (intussuscipiens). Once this prolapse has occurred, lymphatic and venous congestion develops, resulting in edema, strangulation, ischemia, and ultimately necrosis. Additionally, the lumen of the intussuscepted portion of the bowel collapses, causing intestinal obstruction. Intussusception is fatal if spontaneous reduction does not occur and it is left untreated; therefore, prompt diagnosis and treatment are critical for successful management.
PATHOGENESIS AND EPIDEMIOLOGY
Intussusception is the most common cause of intestinal obstruction in children under 2 years of age. While it may occur at any age, intussusception is uncommon prior to 3 months of age, and children ages 3 months to 3 years are most commonly affected. There is a peak in incidence between 5 and 7 months of age. The worldwide incidence of intussusception is approximately 75 cases per 100,000 in the first year of life. Intussusception occurs twice as often in boys as in girls.
Pediatric intussusception is idiopathic (without an identifiable lead point) in 90% of cases. A majority of these cases are ileocolic (Fig. 399-1). The mechanism is hypothesized to be an extra mucosal lead point such as Peyer’s patch hypertrophy or mesenteric lymphadenitis. Viral gastroenteritis (most commonly adenovirus), Henoch-Schönlein purpura, intestinal lymphoid hyperplasia, and meconium ileus have all been associated with intussusception (Table 399-1). An association between intussusception and the tetravalent live attenuated rotavirus vaccine was identified in 1999. The peak incidence appeared within 2 weeks after administration of the first dose in infants 3 to 6 months of age. The manufacturer voluntarily withdrew the vaccine from the United States market, and 2 newer, oral attenuated rotavirus vaccines have since been licensed in the Unite States: the pentavalent rotavirus vaccine (RotaTeq) in 2006 and the monovalent rotavirus vaccine (Rotarix) in 2008. While prelicensure clinical trials did not reveal an increased risk of intussusception, subsequent studies have identified a small, but significant increased risk of intussusception following administration of these vaccines.
TABLE 399-1ETIOLOGIES OF PEDIATRIC INTUSSUSCEPTION |Favorite Table|Download (.pdf) TABLE 399-1ETIOLOGIES OF PEDIATRIC INTUSSUSCEPTION
|Hypertrophy of Peyer’s patch |
|Secondary/Pathologic Lead Point |
|Meckel diverticulum |
|Intestinal polyp |
|Intestinal duplication |
|Submucosal hematoma |
|Tumors (benign or malignant) |
|Ectopic pancreas |
|Iatrogenic (suture line, feeding tubes) |
Air contrast enema demonstrating air outlining the intussusceptum (arrow) within the colon.
Only 10% of pediatric intussusception can be attributed to a pathologic lead point, which include Meckel diverticulum, intestinal polyps, intestinal duplication, hemangioma, suture line, appendix, tumors, and ectopic pancreas. Pathologic lead points should be suspected in children over 2 years of age with intussusception or in children with recurrent intussusceptions. In children with classic symptoms and normal contrast enema, small ...