Intussusception is most common in infants and is three times more common in males than in females. It typically occurs between ages 3 months and 3 years, with a peak incidence between ages 6 and 9 months.

Studies suggest that intussusception may be linked to viral infections because seasonal peaks are noted—in late spring and early summer, coinciding with the peak incidence of enteritis, and in midwinter, coinciding with the peak incidence of respiratory tract infections.

The cause of most cases of intussusception in infants is unknown. In older children, polyps, alterations in intestinal motility, hemangioma, lymphosarcoma, lymphoid hyperplasia, or Meckel’s diverticulum may trigger the process. In adults, intussusception usually results from benign or malignant tumors (65% of patients). It may also result from polyps, Meckel’s diverticulum, gastroenterostomy with herniation, or an appendiceal stump. In the elderly, decreased GI elasticity and motility can lead to intussusception.

When a bowel segment (the intussusceptum) invaginates, peristalsis propels it along the bowel, pulling more bowel along with it; the receiving segment is the intussuscipiens. This invagination produces edema, hemorrhage from venous engorgement, incarceration, and obstruction. If treatment is delayed for longer than 24 hours, strangulation of the intestine usually occurs, with gangrene, shock, and perforation.

In an infant or a child, intussusception produces four cardinal signs and symptoms: