Lifetime Probability of Appendicitis

Appendicitis is the most common cause of emergency abdominal surgery, with a lifetime risk of approximately 7-8% in the United States. About 300,000 appendectomies are performed each year. The peak incidence occurs between ages 10 and 30, with the highest rates in the late teens and early 20s.

Appendicitis occurs when the appendix becomes blocked (usually by hardened stool, lymphoid hyperplasia, or rarely, a tumor), leading to inflammation and bacterial overgrowth. If untreated, the appendix can perforate (rupture), causing peritonitis, a life-threatening abdominal infection. Perforation occurs in about 20-30% of cases and is more common in children under 5 and adults over 65 who may have atypical symptoms and delayed diagnosis.

Classic symptoms include pain starting near the navel and migrating to the lower right abdomen, loss of appetite, nausea, vomiting, and fever. However, atypical presentations are common, making diagnosis challenging. CT scans have improved diagnostic accuracy to over 95%. While appendectomy (usually laparoscopic) has been the standard treatment, recent research suggests that uncomplicated appendicitis can sometimes be treated with antibiotics alone, with about 70% of patients avoiding surgery in the short term (though 30-40% eventually require appendectomy within 5 years).