Intussusception

Intussusception is the most frequent cause of bowel obstruction in infants and toddlers. It is an acquired invagination of the proximal bowel (intussusceptum) into the distal bowel (intussuscipiens). It was first described in 1674 by Paul Barbette of Amsterdam, defined by Treves in 1899, and operated on successfully in 1873 by John Hutchinson.

Pathophysiology

The intussusceptum telescopes into the distal bowel by peristaltic activity. There may or may not be a lead point. As the mesentery of the proximal bowel is drawn into the distal bowel, it is compressed, resulting in venous obstruction and bowel wall edema. If reduction of the intussusception does not occur, arterial insufficiency will ultimately lead to ischemia and bowel wall necrosis. Although spontaneous reduction can occur, the natural history of an intussusception is to progress to bowel ischemia and necrosis unless the condition is recognized and treated appropriately.

Primary Intussusception

A majority of cases, especially in infants, do not have a lead point and are classified as primary or idiopathic intussusceptions. The cause is generally attributed to hypertrophied Peyer patches within the bowel wall. Intussusception occurs frequently in the wake of an upper respiratory tract infection or an episode of gastroenteritis, providing an etiology for the hypertrophied lymphoid tissue. Adenoviruses in children older than age 2 and, to a lesser extent rotaviruses, have been historically implicated in up to 50% of cases. Other contributing evidence that viruses may play a role in intussusception includes the rise in cases during seasonal respiratory viral illnesses and the increased risk associated with rotavirus immunization. The initial rotavirus vaccine was removed from the market due to a significant increase in the incidence of intussusception. The current immunization formulas available in the United States, RotaTeq and Rotarix, also have been associated with a small increased risk, but these risks are widely thought to be outweighed by the benefits of vaccination.

Secondary Intussusception

An intussusception can have an identifiable lesion that serves as a lead point, drawing the proximal bowel into the distal bowel by peristaltic activity. The incidence of a lead point varies from 1.5–12%, and the presence of a lead point increases in proportion with age. The most common lead point is a Meckel diverticulum followed by polyps and duplications. Other benign lead points include the appendix, hemangiomas, carcinoid tumors, foreign bodies, ectopic pancreas or gastric mucosa, hamartomas from Peutz–Jeghers syndrome ( Fig. 38.1 ), and lipomas. Malignant causes, although rare, increase in incidence with age and include lymphomas and small bowel tumors. Systemic diseases, including Henoch–Schönlein purpura and cystic fibrosis, have been associated with intussusception. Other diseases that may be related to intussusception include celiac disease and Clostridium difficile colitis.