Encyclopedia of Health and Medicine

48 The Gastrointestinal System
gallbladder disease. Dietary fiber helps absorb cholesterol
from consumed foods, reducing the
amount of cholesterol that becomes available in
the bloodstream and for the liver to process.
See also DIET AND HEALTH; ENDOSCOPY; HYPERLIPI-
DEMIA; LIFESTYLE AND HEALTH; MINIMALLY INVASIVE SUR-
GERY; PRIMARY BILIARY CIRRHOSIS; PRIMARY SCLEROSING
CHOLANGITIS.
gastrectomy Partial or complete surgical
removal of the STOMACH, typically to treat STOMACH
CANCER or uncontrollable bleeding resulting from
PEPTIC ULCER DISEASE. Gastrectomy is a major OPERA-
TION, typically an OPEN SURGERY, performed under
general ANESTHESIA that requires several days to a
week in the hospital and 8 to 12 weeks for total
recovery and return to regular activities. An individual’s
course of recovery depends on the reasons
for the surgery. The surgical operation takes two
to three hours. After removing the diseased portion
of the stomach through an abdominal incision
at the lower edge of the left rib cage, the
surgeon connects the remaining portion of the
stomach (or the ESOPHAGUS, when the gastrectomy
is total) to the DUODENUM. A partial (also called
subtotal) gastrectomy leaves a gastric pouch that
can carry on some of the digestive functions of the
stomach. Total gastrectomy, which is less common,
leaves no residual gastric pouch though the
surgeon may construct one by expanding a portion
of the duodenum.
Many people are able to return to normal eating
habits after they recover from the surgery,
though find that they need to eat frequent small
meals to accommodate the smaller stomach and
reduce gastrointestinal distress. Foods that are
high in protein and low in simple sugars are easier
for the small intestine to digest without the aid of
the stomach. Some people have difficulty eating
regular foods after gastrectomy and need to use
NUTRITIONAL SUPPLEMENTS, typically liquid preparations,
to meet their NUTRITIONAL NEEDS.
Risks and complications of gastrectomy include
bleeding, INFECTION, dumping syndrome (RAPID
GASTRIC EMPTYING), and damage to the vagus NERVE
(which regulates gastric PERISTALSIS and other
digestive functions). People who have total gastrectomies,
and many people who have subtotal
gastrectomies, need regular injections of vitamin
B 12 (cyanocobalamin) because the gastric mucosa
is no longer able to produce intrinsic factor, a
chemical substance that allows the SMALL INTESTINE
to absorb this vital nutrient. Vitamin B 12 deficiency
causes pernicious ANEMIA.
See also BARIATRIC SURGERY; CANCER TREATMENT
OPTIONS AND DECISIONS; CRANIAL NERVES; SURGERY BEN-
EFIT AND RISK ASSESSMENT.
gastritis INFLAMMATION of the lining of the STOM-
ACH. There are two broad classifications of gastritis:
erosive and nonerosive. The most common cause
of erosive gastritis is repeated irritation from
ingested substances such as ALCOHOL, aspirin, and
NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS).
The most common cause of nonerosive gastritis is
INFECTION with HELICOBACTER PYLORI, the strain of
BACTERIA that causes PEPTIC ULCER DISEASE. Occasionally
viral infections can cause acute gastritis,
which resolves when the infection runs its course.
Autoimmune gastritis, in which the IMMUNE SYSTEM
attacks the cells that form the mucosal lining of
the stomach, interferes with the absorption of certain
NUTRIENTS, notably vitamin B 12 (pernicious
ANEMIA).
Symptoms include DYSPEPSIA (upset stomach),
PAIN, NAUSEA, VOMITING, and a sensation of fullness.
The diagnostic path may include BARIUM SWALLOW
and endoscopic examination of the ESOPHAGUS,
stomach, and DUODENUM (first segment of the
SMALL INTESTINE and the site of peptic ulcer disease).
The gastroenterologist may biopsy samples
of stomach tissue. Treatment targets the underlying
cause. Eliminating ingestion of the responsible
substance often ends erosive gastritis. ANTIBIOTIC
MEDICATIONS can eradicate H. pylori. Treatment for
autoimmune gastritis focuses on countering any
NUTRITIONAL DEFICIENCY that results as well as eliminating
other sources of irritation to minimize gastric
inflammation.
See also AUTOIMMUNE DISORDERS; COLITIS;
ENDOSCOPY; GASTROENTERITIS; PANCREATITIS; STOMACH
CANCER.
gastroenteritis INFLAMMATION of the SMALL INTES-
TINE. The most common cause of gastroenteritis is
viral INFECTION, though sometimes BACTERIA or PAR-
ASITES are responsible. The inflammation of the
intestinal mucosa (mucus lining of the intestinal