Appendicitis and Appendectomy

1. Appendicitis & Appendectomy Slideshow Pictures
2. Medical Illustrations of Appendix Image Collection
3. Take the Appendicitis Quiz

Medical Author:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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What is the appendix?

The appendix is a closed-ended, narrow tube that attaches to the cecum (the first part of the colon) like a worm. (The anatomical name for the appendix, vermiform appendix, means worm-like appendage.) The inner lining of the appendix produces a small amount of mucus that flows through the appendix and into the cecum. The wall of the appendix contains lymphatic tissue that is part of the immune system for making antibodies. Like the rest of the colon, the wall of the appendix also contains a layer of muscle.

What is appendicitis?

Appendicitis is inflammation of the appendix. It is thought that appendicitis begins when the opening from the appendix into the cecum becomes blocked. The blockage may be due to a build-up of thick mucus within the appendix or to stool that enters the appendix from the cecum. The mucus or stool hardens, becomes rock-like, and blocks the opening. This rock is called a fecalith (literally, a rock of stool). At other times, the lymphatic tissue in the appendix may swell and block the appendix. Bacteria which normally are found within the appendix then begin to invade (infect) the wall of the appendix. The body responds to the invasion by mounting an attack on the bacteria, an attack called inflammation. (An alternative theory for the cause of appendicitis is an initial rupture of the appendix followed by spread of bacteria outside the appendix.. The cause of such a rupture is unclear, but it may relate to changes that occur in the lymphatic tissue that line the wall of the appendix.)

If the inflammation and infection spread through the wall of the appendix, the appendix can rupture. After rupture, infection can spread throughout the abdomen; however, it usually is confined to a small area surrounding the appendix (forming a peri-appendiceal abscess).

Sometimes, the body is successful in containing ("healing") the appendicitis without surgical treatment if the infection and accompanying inflammation do not spread throughout the abdomen. The inflammation, pain and symptoms may disappear. This is particularly true in elderly patients and when antibiotics are used. The patients then may come to the doctor long after the episode of appendicitis with a lump or a mass in the right lower abdomen that is due to the scarring that occurs during healing. This lump might raise the suspicion of cancer.