Appendicitis is an inflammation of the appendix, a 3 1/2-inch-long tube of tissue that extends from the large intestine. No one is absolutely certain what the function of the appendix is. One thing we do know: We can live without it, without apparent consequences.

Appendicitis is a medical emergency that requires prompt surgery to remove the appendix. Left untreated, an inflamed appendix will eventually burst, or perforate, spilling infectious materials into the abdominal cavity. This can lead to peritonitis, a serious inflammation of the abdominal cavity’s lining (the peritoneum) that can be fatal unless it is treated quickly with strong antibiotics.

Sometimes a pus-filled abscess (infection that is walled off from the rest of the body) 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 can perforate or explode and cause peritonitis. For this reason, all cases of appendicitis are treated as emergencies, requiring surgery.

In the U.S., one in 15 people will get appendicitis. Although it can strike at any age, appendicitis is rare under age 2 and most common between ages 10 and 30.

What Causes Appendicitis?

Appendicitis occurs when the appendix becomes blocked, often by stool, a foreign body, or cancer. Blockage may also occur from infection, since the appendix swells in response to any infection in the body.

What Are the Symptoms of Appendicitis?

The classic symptoms of appendicitis include:

Dull pain near the navel or the upper abdomen that becomes sharp as it moves to the lower right abdomen. This is usually the first sign.
Loss of appetite
Nausea and/or vomiting soon after abdominal pain begins
Abdominal swelling
Fever of 99-102 degrees Fahrenheit
Inability to pass gas
Almost half the time, other symptoms of appendicitis appear, including:

Dull or sharp pain anywhere in the upper or lower abdomen, back, or rectum
Painful urination and difficulty passing urine
Vomiting that precedes the abdominal pain
Severe cramps
Constipation or diarrhea with gas
If you have any of the mentioned symptoms, seek medical attention immediately, because timely diagnosis and treatment is very important. Do not eat, drink, or use any pain remedies, antacids, laxatives, or heating pads, which can cause an inflamed appendix to rupture.