Encyclopedia of Health and Medicine

R
rapid gastric emptying A disorder, also called
dumping syndrome, in which food moves from
the STOMACH into the SMALL INTESTINE incompletely
digested, resulting in the small intestine attempting
to digest solid food particles. Normally the
digestive content that reaches the small intestine
is fairly liquefied. The incomplete gastric digestion
causes various gastrointestinal symptoms and
leads to MALABSORPTION. Rapid gastric emptying
typically occurs in people who have had stomach
surgery, particularly BARIATRIC SURGERY for weight
loss. Some research studies suggest that rapid gastric
emptying in people who have not had stomach
surgery may be an early sign of type 2
DIABETES. The diagnostic path may include gastroscopy
and BARIUM SWALLOW to rule out other
conditions. Treatment integrates dietary changes
and medications to slow PERISTALSIS. Dietary
changes include eating six small, low-carbohydrate
meals throughout the day and drinking liquids
between, rather than with, meals.
See also ENDOSCOPY.
rebound tenderness A clinical sign of PERITONITIS
(generalized INFLAMMATION and INFECTION of the
abdominal cavity). During abdominal palpation,
the doctor presses slowly and firmly on the
abdomen, then suddenly releases the pressure.
The person feels a stabbing PAIN with release when
the result is positive and notices no change when
the result is negative. Rebound tenderness has a
high level of accuracy for both positive and negative
results. Rebound tenderness often appears as
referred pain in appendicitis. The pressure and
release action applied to the left side of the
abdomen results in the person feeling pain on the
right side of the abdomen, at the approximate
location of the appendix.
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See also DIGITAL RECTAL EXAMINATION (DRE).
rectal fistula An abnormal opening in the wall
of the RECTUM, often connecting the rectum with
another structure such as the URETHRA (rectourethral
fistula), the VAGINA (rectovaginal fistula),
or the ANUS (anorectal fistula). Rectal fistulas
may be congenital or acquired. Congenital fistulas
often occur in combination with other congenital
anomalies, notably those affecting the HEART such
as tetralogy of Fallot (a collective of malformations
in the structure of the heart). Acquired rectal fistulas
may be idiopathic (without detectable
cause), though are more likely to occur in people
who have inflammatory conditions that affect the
gastrointestinal tract such as INFLAMMATORY BOWEL
DISEASE (IBD). RADIATION THERAPY as treatment for
PROSTATE CANCER, CERVICAL CANCER, OVARIAN CANCER,
COLORECTAL
CANCER, or other cancers in the
abdomen can weaken the rectal wall, allowing fistulas
to develop. As well, fistulas involving any
portion of the gastrointestinal tract are frequent
complications of HIV/AIDS.
Symptoms vary with the location of the fistula
though often include FECAL INCONTINENCE or inappropriate
presence of stool in the other involved
structure. The diagnostic path may include DIGITAL
RECTAL EXAMINATION (DRE), BARIUM ENEMA, and sigmoidoscopy
(endoscopic examination of the lower
COLON). Treatment is surgery to repair the fistula,
which can sometimes be extensive when the fistula
is long or deep. Potential complications vary
according to the nature of the OPERATION necessary.
In many people the surgical repairs end the symptoms
and the person returns to his or her usual
activities with no further problems. In some people,
complications such as fecal incontinence arise
or new fistulas occur.