Appendicitis is an inflammation of the appendix, a 3 1/2-inch-long tube of tissue that extends from the large intestine. The appendix contains specialized tissue that can produce antibodies, but no one is absolutely certain what its function is. One thing we do know: We can live without it, without apparent consequences.
Appendicitis is a almost always a medical emergency that requires prompt surgery to remove the appendix. Left untreated, an inflamed appendix may eventually burst, or perforate, spilling infection into the abdominal cavity. This can lead to peritonitis, a serious infection of the abdominal cavity's lining that can be fatal unless it is treated quickly with strong antibiotics and surgery to remove the pus.
Sometimes a pus-filled abscess forms outside the inflamed appendix. Scar tissue then "walls off" the appendix from the rest of the abdomen, preventing infection from spreading. An abscessed appendix is a less urgent situation, but unfortunately, it cannot always be identified without surgery. For this reason, all cases of appendicitis are treated as emergencies.
In the U.S., about one in 15 people gets appendicitis. Although it can strike at any age, appendicitis is rare under age 2 and most common between ages 10 and 30, with the highest incidence in the 10- to 19 year-old age group.
What Causes Appendicitis?
Appendicitis occurs when the tube-shaped appendix becomes blocked, often by fecal material, a foreign body, or cancer. Blockage may also occur from infection, because the appendix swells in response to any infection in the body. As the wall of the appendix expands, its opening gradually closes.