Epidemiology


Etiology


  • Mostly idiopathic
    • ∼ 75% of cases have no identifiable lead point
      • Lead point: An intraperitoneal anomaly or abnormality that obstructs or tethers the bowel, provoking intussusception.
    • More common in children 3 months to 5 years of age
  • Pathological lead points
    • Defined as intraperitoneal anomalies or abnormalities that obstruct or tether the bowel and act as lead points in the process of intussusception
      • Meckel diverticulum (most common in children)
      • Intestinal polyps or other benign tumors (most common in adults and 2nd most common in general)
      • Enlarged Peyer patches: individuals with a history of a recent viral infection or immunization (e.g., rotavirus or adenovirus)
        • Viral stimulation of lymphoid follicles within the small intestine (Peyer patches) can lead to hypertrophy of those areas, which can then act as lead points that become trapped by peristalsis and dragged into a distal portion of the intestine.
        • The most common location is at the ileocecal junction, as in this patient, and is likely due to a dense concentration of Peyer patches in the terminal ileum.

Pathophysiology


Clinical features


  • Classic Triad: Intermittent, colicky abdominal pain, a “sausage-shaped” palpable mass in the abdomen, and “currant jelly” stool.
  • Pain: Sudden, severe, crampy pain causing the child to draw their knees to their chest, followed by periods of being calm or lethargic.
  • Stool: “Currant jelly” stool (a mix of blood, mucus, and sloughed mucosa) is a late sign indicating vascular compromise.
  • Vomiting: Can be nonbilious initially but progresses to bilious vomiting as obstruction develops.
  • Physical Exam: A sausage-shaped mass may be palpated, typically in the RUQ. The RUQ may also feel empty (Dance’s sign) due to the displacement of the cecum.

Diagnostics

  • Ultrasound is the gold standard diagnostic tool.
  • Classic Finding: “Target sign” or “doughnut sign” on a transverse view of the ultrasound.
  • Abdominal X-ray may be done to look for signs of obstruction or perforation but is not as sensitive as ultrasound.

Treatment