Encyclopedia of Health and Medicine

appendix A small, fingerlike projection, sometimes
called the vermiform appendix, extending
from the bottom of the CECUM, the first segment of
the large intestine (COLON). Historically health professionals
have viewed the appendix as a vestigial
structure with no functional purpose. However,
recent research identifies clusters of GUT-ASSOCI-
ATED LYMPHOID TISSUE (GALT), fragments of lymphoid
tissue, within the lining of the appendix. Though
researchers do not yet understand the role of
GALT, they know it belongs to the IMMUNE SYSTEM
and has functions related to the IMMUNE RESPONSE.
It appears that the immune functions of the
appendix, like those of the THYMUS, are most active
early in life. Researchers are studying the relationappendix
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surgeon inserts special instruments. LAPAROSCOPIC
SURGERY often requires only an overnight stay in
the hospital, with return to normal activities in
three to four weeks. Laparoscopic appendectomy
is the operation of choice for most circumstances
of simple appendicitis in which INFLAMMATION and
INFECTION remain confined to the appendix and the
diagnosis is clear-cut. The surgeon may choose to
convert a laparoscopic to an open procedure
should there be any complicating factors once the
surgery begins.
Risks of appendectomy, open or laparoscopic,
include leakage of intestinal content into the peritoneal
cavity, which can result in PERITONITIS, or
postoperative ABSCESS (pocket of infection). To
safeguard against these complications, postoperative
care includes intravenous ANTIBIOTIC MEDICA-
TIONS during the hospital stay and a course of oral
antibiotics following hospital discharge. As with
any surgery, reaction to ANESTHESIA and bleeding
during or after the operation are also risks. Full
recovery after appendectomy for simple appendicitis
is the norm, with most people returning to
their usual activities within six weeks (up to eight
weeks for strenuous physical activity such as competitive
sports).
See also ENDOSCOPY.
appendicitis INFLAMMATION of the APPENDIX.
Because the appendix is so narrow, inflammation
can rapidly cause it to swell closed, trapping BAC-
TERIA-laden intestinal matter. This sets the stage
for INFECTION that can spread to involve nearby
structures.
Appendicitis is an emergency that
requires immediate surgery.
The classic symptoms of appendicitis include
• PAIN in the lower right abdomen
• NAUSEA, VOMITING, and aversion to food
• tendency to lie in somewhat of a fetal position,
often on the right side with the knees drawn
toward the chest
However, more than a third of people who
have appendicitis have atypical symptoms that
may include diffuse (generalized) abdominal discomfort,
pain referred to the back or shoulder
area, or symptoms that mimic other health conditions
ranging from DYSPEPSIA (indigestion) to URI-
NARY TRACT INFECTION (UTI). Further, there are no
definitive causes of appendicitis, though often the
surgeon or pathologist detects particles of food or
fecal matter lodged in the appendix. The key risk
of appendicitis is that the inflamed appendix may
perforate (rupture), spilling intestinal debris and
infectious matter into the peritoneal cavity. The
resulting widespread contamination evolves
quickly to PERITONITIS, a life-threatening infection.
The diagnostic path begins with a physical
examination to determine the quality of the pain.
Key signs of appendicitis during examination
include rebound tenderness (increased pain when
the doctor presses slowly downward on the
abdomen and then suddenly releases the pressure)
and pain (often intense) with pressure applied
directly over the location of the appendix. A DIGI-
TAL RECTAL EXAMINATION (DRE) also often elicits a significant
pain response. A complete blood count
(CBC) may reveal the inflammatory process or an
infection.
Surgical removal of an inflamed appendix
(APPENDECTOMY) provides the only conclusive diagnosis
of appendicitis. ANTIBIOTIC MEDICATIONS generally
are not effective in treating appendicitis
because the infection is generally well under way
by the time of diagnosis and the risk of peritonitis
or other complicating factors is very high.
See also GALLBLADDER DISEASE; PELVIC INFLAMMA-
TORY DISEASE (PID).