Which of the following most often initiates the development of acute appendicitis?

C. Obstruction of the appendiceal lumen.

DISCUSSION: The majority of patients with acute appendicitis have an obstructed lumen that is due to either hyperplasia of the lymph follicles in the wall of the appendix or a fecalith. The obstruction creates a site where the bacteria in the lumen multiply rapidly, producing exotoxins and endotoxins that then ulcerate the mucosa, allowing pathogenic organisms to enter the wall of the appendix. An inflammatory process follows that can extend to the serosa, and penetration through the serosal layer causes generalized peritonitis.