Causes and Risk Factors of Appendicitis

Primary Pathophysiologic Mechanism

Appendicitis is primarily caused by obstruction of the appendiceal lumen, which leads to increased intraluminal pressure, bacterial overgrowth, inflammation, and potential perforation in patients with appendicitis, according to the World Journal of Emergency Surgery 1

Elderly patients have significantly higher rates of complicated appendicitis (18-70%) compared to younger patients (3-29%), with vascular sclerosis of the appendix, luminal narrowing from fibrosis, and fat infiltration of muscular layers creating structural weakness predisposing to early perforation, as reported by the World Journal of Emergency Surgery 3
Lymphoid hyperplasia is the predominant cause in children and adolescents, with the lifetime risk of appendicitis peaking between ages 10-30 years, according to the World Journal of Emergency Surgery 1

The presence of intraluminal fecaliths or appendicoliths on imaging is predictive of perforation, with an odds ratio of 2.47-2.67, and CT findings of intraluminal fecaliths have sensitivity of 55.4% and specificity of 68.3% for predicting perforation, as reported by the Journal of the American College of Radiology 2

Lifetime risk varies by geography: 9% in the USA, 8% in Europe, and 2% in Africa, with incidence rates in developed countries ranging from 5.7-50 per 100,000 inhabitants per year, according to the World Journal of Emergency Surgery 1
The American College of Radiology recommends considering neoplasia in older patients with prolonged symptoms, as they may require right hemicolectomy rather than simple appendectomy if malignancy is confirmed 2