I. Epidemiology, risk factors, and pathophysiology

  1. Consists of invagination of a proximal segment of intestine (the intussusceptum) into a more distal segment (the intussuscipiens)-Almost always the ileum unto the colon
  2. Most common in children < 2y; peak incidence 6-9mo
  3. Can be fatal within 1wk if untreated
  4. Risk factors
    1. Male predominance 3:2 (Arch. Ped. Adol. Med. 154:250, 2000--AFP)
    2. Antibiotic use
      1. In a case-control study of 93 pts < 4yo with intussusception and 353 age- and sex-matched controls, receipt of antibiotics in prior 48h was associated with OR 4.15 for intussusception (sig.).  For cephalosporins the OR was 22.49 (Arch. Pediat. Adol. Med. 157:54, 2003--JW)

II. Clinical findings and diagnosis
  1. "Classic triad": colicky abdominal pain, vomiting, and "currant jelly" stools-only present in 30-40% of patients
  2. Physical findings
    1. Pathognomonic physical finding is a sausage-shaped mass in RUQ or epigastrium, with feeling of emptiness in RLQ ("Dance's sign")
    1. Patients often hold hips in flexion
    1. Gross or occult hematochezia occur in 70% of patients
  3. Radiologic findings
    1. Plan abdominal radiographs have high specificity but low sensitivity (Pediat. Emerg. Care 26:281, 2010-JW)
      1. Findings include dilated loops of bowel, air-fluid levels, reduced air in RLQ and soft tissue mass in right or mid-abdomen
      2. Free air, if seen, suggests bowel perforation
    2. Traditionally, barium or air enema are used
      1. May also have the therapeutic effect of resolving the intussusception (80% are reduced with an air enema, but recurrence rate in these cases is 10%)
    3. Ultrasound seems have high sensitivity
      1. Quicker and less invasive than barium enema; consider if pretest probability is low
      2. Findings include tubular mass ("pseudokidney sign") in longiturinal views, and target appearance ("donut sign") in transverse views

III. Management

  1. "Pneumatic reduction" with air enema
  2. Laparotomy if pneumatic reduction is unsuccessful or if shock, peritonitis, perforation, or suspected bowel gangrene are present

(Sources include Core Content Review of Family Medicine, 2012)