Appendicitis is a painful irritation of the appendix, which is a narrow, finger-shaped pouch attached to the large intestine in the lower right side of the abdomen. Appendicitis occurs when the inside of the appendix becomes filled with something that causes it to swell, such as mucus, stool or parasites.
If left untreated, the blood supply to the appendix (which is necessary for it to remain healthy) becomes cut off, and the appendix starts to die. Eventually this will cause rupture to occur as holes develop in the walls of the appendix.
A ruptured (or burst) appendix can be life-threatening. When the appendix ruptures, bacteria infect the organs inside the abdominal cavity, causing peritonitis. This bacterial infection can spread very quickly and be difficult to treat if diagnosis is delayed.
Appendicitis affects 1 in 1,000 people living in the United States. Most cases occur between the ages of 10 and 30. In fact, appendicitis is the most common reason for a child to need emergency abdominal surgery.