Appendicitis
Appendicitis is inflammation and infection of the appendix.
The appendix is a small finger-shaped tube projecting from the large intestine near the point where it joins the small intestine. The appendix may have some immune function, but it is not an essential organ.
Except for trapped hernias, appendicitis is the most common cause of sudden, severe abdominal pain and abdominal surgery in the United States. Appendicitis is most likely to occur between the ages of 10 and 30.
The cause of appendicitis is not fully understood. In most cases, a blockage inside the appendix probably starts a process in which the appendix becomes inflamed and infected. If inflammation continues without treatment, the appendix can rupture. A ruptured appendix spills bacteria-laden intestinal contents into the abdominal cavity, causing peritonitis (see Section 9, Chapter 132), which may result in a life-threatening infection. A rupture also may cause an abscess (a pus-filled pocket of infection) to form. In a woman, the ovaries and fallopian tubes may become infected, and the resulting blockage of the fallopian tubes may cause infertility. A ruptured appendix also may allow bacteria to infect the bloodstream--a life-threatening condition called sepsis (see Section 17, Chapter 191).
Symptoms
Fewer than 50% of people with appendicitis have the traditionally described symptoms of nausea, vomiting, and severe pain in the lower right abdomen. Pain may begin suddenly in the upper abdomen or around the navel; then nausea and vomiting develop. After a few hours, the nausea passes, and the pain shifts to the right lower portion of the abdomen. When a doctor presses on this area, it is tender, and when the pressure is released, the pain may increase sharply (rebound tenderness). A fever of 100 to 101° F (37.7 to 38.3° C) is common.
Pain, particularly in infants and children, may be widespread rather than confined to the right lower portion of the abdomen. In older people and in pregnant women, the pain is usually less severe, and the area is less tender.
If the appendix is ruptured, pain and fever may become severe. Worsening infection can lead to shock (see Section 3, Chapter 24).
Diagnosis
A doctor may suspect appendicitis after reviewing the person's symptoms and examining the abdomen. A blood test shows a moderate increase in the white blood cell count in response to the infection. Usually, in the early stages of appendicitis, most tests--including x-rays, ultrasound scanning, and computed tomography (CT)--are useless. Typically, exploratory surgery is performed immediately if the suspicion of appendicitis is strong.
Treatment
Surgery is the main treatment. In nearly 15% of operations for appendicitis, the appendix is found to be normal. However, delaying surgery until the cause of the abdominal pain is certain can be fatal: An infected appendix can rupture less than 24 hours after symptoms begin. If appendicitis is found, the appendix is removed (appendectomy). Even when appendicitis is not found to be the cause, the appendix is usually removed.
With an early operation, the chance of death from appendicitis is very low. The person can usually leave the hospital in 2 or 3 days, and convalescence is normally quick and complete.
For a ruptured appendix, the prognosis is more serious. Fifty years ago, a rupture often was fatal. Surgery and antibiotics have lowered the death rate to nearly zero, but repeated operations and a long convalescence may be necessary.
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