Inflammation of the appendix.

Appendicitis occurs when the appendix, a 3—4 in (8-10 cm) worm-like projection of the large intestine, becomes inflamed. The inflammation is caused by hardened feces blocking the appendix channel. Inflammation and infection happen within a matter of hours. If the inflamed appendix bursts, the infection could spread to the abdominal cavity, causing peritonitis or a perforation of the intestine. If a young girl suffers an intestinal perforation, she could develop a severe pelvic infection resulting in sterility.

Appendicitis usually attacks young people between the ages of two and thirty, with teenagers the most likely candidates. One hundred and twenty out of every 100,000 children in the United States undergo appendectomies every year. Some medical professionals believe that many of these surgeries are unnecessary and are making efforts to clarify the diagnostic procedure.

Children of all ages frequently experience stomachaches, and it is often difficult to know...