Etiology

• Sex: ♂ > ♀ (3:2)

• Age

  • Peak incidence: 3–12-month-old infants

  • Otherwise commonly occurs in children 3 months to 5 years of age

  • Uncommon in adults

Intussusception, alongside incarcerated hernia, is one of the most common causes of bowel obstruction in children. It is the most common cause of bowel obstruction in the first two years of life.

• Mostly idiopathic

  • ∼ 75% of cases have no identifiable lead point

  • More common in children 3 months to 5 years of age

• Defined as intraperitoneal anomalies or abnormalities that obstruct or tether the bowel and act as lead points in the process of intussusception [2]

  • 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)

  • Bowel wall thickening in IgA vasculitis

  • Cystic fibrosis [3]

  • Hematoma, hemangioma

  • Enlarged lymph nodes, lymphomas

  • Adhesions

• More likely the underlying cause in patients with recurrent episodes of intussusception; more common in children < 3 months or > 5 years of age

• Imbalance in the bowel wall (idiopathic or via a pathological lead point) → invagination or “telescoping” of a portion of intestinal bowel (intussusceptum) into the distal adjacent bowel loop (intussuscipiens) → impaired lymphatic drainage and increasing pressure in intussusceptum bowel wall → venous impairment → mesenteric vessels congestion → ischemia of intussusceptum bowel wall → sloughing of bowel mucosa (most sensitive to bowel ischemia since it is the furthest from the arterial supply) → transmural necrosis and perforation with prolonged ischemia

• The dysfunctional passage leads to mechanical bowel obstruction → vomiting