Definition

　　Appendicitis is a sudden inflammation of the appendix, a small, finger-shaped tube that branches off the large intestine.

　　Causes, incidence, and risk factors

　　Appendicitis is one of the most common causes of emergency abdominal surgery in children. Approximately 4 appendectomies per 1,000 children are done annually in the United States.

　　Appendicitis is more common in males than in females, and incidence peaks in the late teens and early 20s. The condition is uncommon among children younger than 2, but it can occur.

　　Appendicitis generally follows obstruction of the appendix by feces (fecalith), a foreign body, or rarely, a tumor. Typically, the first symptom is crampy or "colicky" pain around the navel (periumbilical). There is usually a marked reduction in or total absence of appetite, often associated with nausea, and occasionally, vomiting and low grade fever.

　　As the inflammation in the appendix increases, the pain tends to move downward and to the right (right lower quadrant) and localizes directly above the position of the appendix at a point called "McBurney's point." If a line is drawn from the navel to the prominence on the right pelvic bone (right superior iliac crest) and divided into thirds, McBurney's point is two-thirds of the line from the navel.

　　Pressing the abdomen at McBurney's point causes tenderness in a patient with appendicitis. When the abdomen is pressed, held momentarily, and then rapidly released, the patient may experience a momentary increase in pain. This "rebound tenderness" suggests inflammation has spread to the peritoneum.

　　If the appendix ruptures, the pain may disappear for a short period and the patient may feel suddenly better. However, once peritonitis sets in, the pain returns and the patient becomes progressively more ill. At this time the abdomen may become rigid and extremely tender.

　　Symptoms of appendicitis in young children are seldom typical, so diagnosis is commonly delayed and perforation more likely. Older children, adolescents, and adults are more easily diagnosed.

　　Symptoms

　　· Abdominal pain

　　o Pain may begin in the upper-middle abdomen (epigastric), then develop to sharp localized pain

　　o Pain may shift from the epigastric area to become most intense in the lower right side of the abdomen ("typical" case), tenderness of this area is common

　　o Pain initially may be vague, but becomes increasingly more severe

　　· Point tenderness, especially over the right lower quadrant of the abdomen

　　· Nausea and vomiting

　　· Fever usually occurs within several hours

　　Abdominal pain may be worse when walking or coughing. The patient may prefer to lie still; sudden jarring motions or bumping can cause pain.

　　Later symptoms:

　　· Fever

　　· Loss of appetite

　　· Nausea

　　· Vomiting

　　· Constipation

　　· Rectal tenderness

　　· Chills and shaking

　　Additional symptoms that may be associated with this disease include bloody urine (microscopic hematuria).

　　Signs and tests

　　With appendicitis, pain increases when the abdomen is gently pressed and then the pressure is suddenly released. Touching the abdomen may cause a spasm of the abdominal muscles if peritonitis is present. Rectal examination may also cause pain, localized on the right side.

　　The health care provider may perform other tests, including having the patient lie on his or her back with the following:

　　· The right leg is extended straight up.

　　· The knee and hip are flexed, and then the leg is rotated inward and outward.

　　· The lower left portion of the abdomen is palpated.

　　Each of these actions will cause pain in the lower right quadrant of the abdomen of a person with appendicitis.

　　Appendicitis may be strongly suspected based on the following tests:

　　· CBC, often shows an increased white blood cell count

　　· Abdominal sonography

　　· Abdominal CT scan

　　The surgeon may confirm the diagnosis during an exploratory laparotomy. The operation may be done as an open procedure or through a laparoscopic approach that uses a small camera and requires a smaller incision.

　　It is important to realize that not all surgical explorations for appendicitis reveal an abnormal appendix. Approximately 10-15% of operations for suspected appendicitis reveal either no obvious abnormality, or a disease process other than appendicitis. This relatively high rate of "negative appendectomies" is tolerated because the consequences of not diagnosing appendicitis in patients with abdominal pain can be severe and sometimes life-threatening.

　　If an operation for suspected appendicitis reveals a normal appendix, the surgeon will probably remove the appendix anyway, and then explore the rest of the abdomen for other possible causes of pain. In some cases, this may require extension of the surgical incision.

　　Treatment

　　For uncomplicated appendicitis, surgery (appendectomy) is performed as soon as possible after the diagnosis is made. Little preparation is required. If an abscess is suspected, the patient is stable, there are no signs of peritonitis, and it is presumed that appendicitis occured some time ago, the surgery may be delayed until antibiotic therapy has reduced the infection.

　　In cases where the diagnosis is uncertain, an ultrasound or CT scan of the abdomen may be useful.

　　Expectations (prognosis)

　　Early surgery has a death rate of less than 0.5%.

　　Complications

　　· Perforation of the intestines

　　· Gangrene (tissue death) of the intestines

　　· Peritonitis

　　· Abscess

　　· Fistulas

　　Calling your health care provider

　　Call your health care provider if you develop abdominal pain in the lower right quadrant or any other symptoms suggestive of appendicitis.