Acute inflammation or infection of the vermiform appendix


  • Most common surgical emergency of childhood
  • Incidence rate (per 10,000 person-years):
    • 2 in 0- to 4-year olds,
    • 10 in 5- to 9-year olds,
    • 15 in 10- to 14-year olds
  • 293,000 admissions in the United States in 2010
  • 80,000 pediatric appendectomies per year in United States
  • Most commonly seen in 2nd decade of life; <5% are aged 0 to 4 years old
  • Affects boys more commonly than girls


  • Acute inflammation of the appendiceal lumen is caused by obstruction (i.e., by a fecalith, calculi, parasites, hyperplastic lymphoid tissue, or tumor).
  • Appendix is innervated by somatic afferent nerves of the 10th dermatome overlying the epigastrium and periumbilical areas.
  • In the first phase of pain, occlusion causing increasing wall tension results in vague pain poorly referred to this area.
  • Increasing wall tension and full-thickness serositis results in inflammation of surrounding tissues, and the second phase of pain is localized to the area in which the appendix is lying.
  • In 85% of patients, this tenderness is located at McBurney point; however, pelvic, retrocecal, retroperitoneal, inguinoscrotal, or other orientations will result in variance of location and intensity of this pain.

Commonly Associated Conditions

Neonatal appendicitis is associated most commonly with prematurity, inguinal hernia, and Hirschsprung disease.

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