Etiology

Caused by obstruction of the appendiceal lumen due to:

• Lymphoid tissue hyperplasia (60% of cases): most common cause in children and young adults

• Appendiceal fecalith and fecal stasis (35% of cases): most common cause in adults

• Neoplasm (uncommon): more likely in patients > 50 years of age [4]

• Parasitic infestation (uncommon): e.g., Enterobius vermicularis, Ascaris lumbricoides, and species of the Taenia and Schistosoma genera

• Obstructed proximal appendiceal lumen (closed-loop obstruction), resulting in:

  • Stasis of mucosal secretions → bacterial multiplication and local inflammation → transmural spread of infection → clinical features of appendicitis

  • Increased intraluminal pressure → obstruction of veins → edema of the appendiceal walls → obstruction of capillaries → ischemia → gangrenous appendicitis with/without perforation

• Inflammation can spread to serosa, leading to peritonitis