Triad of bilious emesis, abdominal mass, and blood per rectum is seen in less than 10% of cases Intussusception should be considered in infants and toddlers with emesis and altered mental status Children with intussusception may arrest during a pneumatic reduction and therefore the clinical team must be prepared After successful enema reduction, intussusception recurs in approximately 5% of cases within the first 48 hours Current Evidence Intussusception occurs when one segment of bowel invaginates into a more distal segment This is the leading cause of acute intestinal obstruction in infants, and it occurs most commonly between and 12 months of age The most common intussusception is ileocolic but the small bowel may intussuscept into itself Typically, this small bowel intussusception then prolapses through the ileocecal valve ( Figs 116.6 and 116.7 ) The intussusception continues through the colon a variable distance, occasionally as far as the rectum, where it can be palpated on rectal examination Colocolic intussusceptions are rare In infants, the lead point for ileocolic intussusception may be hypertrophied Peyer patches In children older than years of age, a specific lead point such as a polyp, a Meckel diverticulum, an intestinal duplication, or a tumor should be considered A diarrheal illness or viral syndrome may occur several days to a week before the onset of abdominal pain and obstruction Henoch–Schönlein purpura has been associated with intussusception (generally small bowel–small bowel) Small bowel–small bowel intussusceptions may cause symptoms but generally selfresolve Clinical Considerations Clinical Recognition The primary manifestation of intussusception is colicky abdominal pain in an infant or toddler Children with intermittent abdominal pain and vomiting, especially if bilious, should be evaluated for intussusception The condition of the patient is highly variable between being happy and playful between episodes to critically ill children with evidence of peritonitis and shock Occasionally, the primary complaint may be blood per rectum or vomiting and altered mental status