Question

Which is the most common site of intussusception?

• A. Ileocecal
• B. Ileoileal
• C. Ileocolic
• D. Colicocolic

Hint:

Most common site of intussusception: Ileocolic ($>85\%$). Most common pathological lead point: Meckel's Diverticulum. Peak age: $5\text{--}9\text{ months}$.

Answer 1

The Correct Option is C

Concept:
Intussusception is the telescoping or invagination of a proximal segment of the bowel (the intussuscipiens) into an adjacent, immediately distal bowel segment (the intussuscipiens).
It represents the most common cause of acute intestinal obstruction in infants and young children between 3 months and 3 years of age.
Explanation:
• In over $85\text{--}90\%$ of pediatric cases, intussusception is idiopathic and occurs in the ileocolic region, where the terminal ileum invaginates through the ileocecal valve into the colon.

• This anatomical site is particularly vulnerable because the terminal ileum contains abundant lymphoid tissue (Peyer patches) that readily undergoes hypertrophy following common viral infections (such as adenovirus, rotavirus, or enterovirus), serving as a physiological lead point.

• Ileoileal intussusception (small-bowel intussusception) is less frequent and is often transient, non-obstructive, or associated with a pathological lead point like a Meckel diverticulum or Henoch-Schönlein purpura hematoma.

• Colicocolic intussusception accounts for less than $5\%$ of cases and typically occurs in older children or adults in association with discrete colonic polyps or neoplasms.

• Ileocecal intussusception refers specifically to invagination of the ileocecal valve itself, which is less precise than the classic ileocolic progression.
Final Answer:
The most frequent anatomical subtype of pediatric intussusception is ileocolic intussusception.