Encyclopedia of Health and Medicine

gastroenteritis 49
wall) reduces the small intestine’s ability to absorb
NUTRIENTS and fluid. People often refer to gastroenteritis
as “stomach flu,” though this is inaccurate;
the “flu” or influenza is a viral infection of the
pulmonary system.
Symptoms and Diagnostic Path
Symptoms of gastroenteritis include DIARRHEA,
abdominal cramping, and occasionally ABDOMINAL
DISTENTION. Depending on the cause of the infection,
the diarrhea can be profuse or bloody;
bloody diarrhea requires medical evaluation.
There may also be FEVER and VOMITING.
Symptoms that extend beyond two or
three days in children or the elderly, or
in a person of any age who cannot keep
any fluids down, require medical evaluation
to prevent DEHYDRATION.
The diagnostic path may include laboratory
tests to determine the presence of pathogens
(agents of infection) in the stool and blood tests to
help identify the extent and nature of infection.
The doctor may take stool samples or a rectal swab
to determine whether bacterial or parasitic
pathogens are present, which would require treatment
with the appropriate medications. Bacterial
gastroenteritis most often results from consuming
contaminated food or water. The doctor may recommend
ANTIEMETIC MEDICATIONS to quell nausea
and ANTIDIARRHEAL MEDICATIONS to reduce diarrhea,
depending on the cause and extent of the symptoms.
Noninfectious forms of gastroenteritis include
Crohn’s disease and radiation gastroenteritis.
Crohn’s disease is a component of INFLAMMATORY
BOWEL DISEASE (IBD), which many doctors believe is
an autoimmune disorder with a genetic component
in which the IMMUNE SYSTEM attacks the
intestinal mucosa. The attacks result in small
ulcerations that often bleed. The enteric symptoms
are chronic; treatment targets the underlying disease.
Radiation gastroenteritis results from damage
to the intestinal mucosa that occurs with
RADIATION THERAPY to the abdomen, and may be
acute (limited to the course of radiation therapy)
or chronic (signaling permanent changes in the
intestinal mucosa).
COMMON ENTERIC PATHOGENS
Pathogen Type Route of Infection
astrovirus VIRUS contaminated food or water
person-to-person
calicivirus virus contaminated food or water
person-to-person
Cryptosporidium PARASITE contaminated water
animal-to-person
person-to-person
Cyclospora parasite contaminated food or water
cayetanensis
person-to-person
enteric adenovirus virus contaminated food or water
person-to-person
Escherichia coli BACTERIA contaminated food or water
person-to-person
Giardia lamblia parasite contaminated water
person-to-person
Listeria bacteria contaminated food
person-to-person
Microsporidia parasite unknown
rotavirus virus contaminated food or water
person-to-person
Salmonella bacteria contaminated food
reptile-to-person
Staphylococcus bacteria contaminated food
enterotoxin
person-to-person
Treatment Options and Outlook
Adequate fluid replacement and other supportive
measures are the only treatment necessary for
viral gastroenteritis, which typically runs its
course in three to five days. Young children, older
adults, and people who have serious chronic
health care conditions are at greatest risk for complications
from viral gastroenteritis, though most
people recover fully. Bacterial and parasitic gastroenteritis
require treatment with the appropriate
medications to eliminate the causative PATHOGEN,