Acute appendicitis is inflammation of the appendix, the narrow, finger-shaped organ that branches off the first part of the large intestine on the right side of the abdomen. Although the appendix is a vestigial organ with no known function, it can become diseased. In fact, acute appendicitis is the most common reason for abdominal surgery in the world.

If it is not treated promptly, there is the chance that the inflamed appendix will burst, spilling fecal material into the abdominal cavity. The usual result is a potentially life-threatening infection (peritonitis), but the infection may become sealed off and form an abscess.

Appendicitis is uncommon among older people, and symptoms are generally mild, so that diagnosis of the acute episode is often not made. Members of this age group are thus at greater risk for rupture with peritonitis or abscess formation.

What Causes Acute Appendicitis?

  • Appendicitis is usually caused by a bacterial infection, although the reason the appendix becomes infected is unknown.
  • The appendix may become obstructed by a lump of feces, calcium salts, and fecal debris (called fecaliths) or tumors (rarely), leading to inflammation and infection.
  • Swelling and inflammation lead to infection, blood clot, or rupture of the appendix.
  • Lymphoid hyperplasia is associated with inflammatory and infectious disorders such as Crohn disease, measles, amebiasis, gastroenteritis, respiratory infections, and mononucleosis.

Symptoms of Acute Appendicitis

  • In very young children or people over age 65, symptoms of acute appendicitis may be deceptively mild. Otherwise, symptoms can vary widely and may include the following:
  • Vague discomfort or tenderness near the navel (early in an attack), migrating to the right lower quadrant of the abdomen
  • Sharp, localized, persistent pain within a few hours
  • Pain that worsens with movement, deep breathing, coughing, sneezing, walking or being touched
  • Constipation and inability to pass gas, possibly alternating with diarrhea
  • Low fever (below 102°F). A high fever (possibly accompanied by chills) may indicate an abscessed appendix
  • Rapid heartbeat
  • Abdominal swelling (in late stages)
  • Abrupt cessation of abdominal pain after other symptoms occur, indicating the appendix has burst—an emergency
  • Nausea and vomiting (in some cases)
  • Loss of appetite
  • Coated tongue and bad breath
  • Painful and/or frequent urination
  • Blood in the urine
  • Abdominal swelling or bloating, especially in infants

Prevention of Acute Appendicitis

There are no specific preventive measures. Contrary to popular belief, swallowing seeds from fruit does not precipitate appendicitis.

Diagnosis of Acute Appendicitis

  • Physical examination is necessary to rule out other disorders that produce symptoms similar to those of appendicitis.
  • A rectal examination may be performed.
  • Blood and urine samples will be taken for analysis.
  • CT (computed tomography) scan or an abdominal x-ray may be necessary.

How to Treat Acute Appendicitis

  • Call your doctor immediately. If you are unsure of your symptoms, take your temperature every two hours and keep a record for your doctor.
  • The appendix must be removed (appendectomy) either through a small incision or with a special instrument (laparoscope). Surgery should not be delayed more than a few hours.
  • If an abscess has formed, your doctor may drain it and prescribe antibiotics. Appendectomy may be scheduled for a later date.

When to Call a Doctor

Call a doctor immediately if you experience symptoms that may indicate appendicitis.



Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 17 Aug 2011

Last Modified: 07 Oct 2014