A rupture is when the appendix bursts or tears, and may occur if appendicitis is not diagnosed quickly and goes untreated. Infants, young children, and older adults are at highest risk of a rupture. A ruptured appendix can lead to peritonitis and abscess. Peritonitis is a dangerous infection that occurs when bacteria and other contents of the torn appendix leak into the abdomen. In people with appendicitis, an abscess usually takes the form of a swollen mass filled with fluid and bacteria. In rare cases, appendicitis complications can lead to organ failure and death.