Gastroenteritis (viral gastroenteritis, stomach flu) is an infection caused by a variety of viruses that results in vomiting and/or diarrhea. Even though it is often called the "stomach flu," it is not caused by the influenza viruses. Viruses that can cause gastroenteritis (stomach flu) include: rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Noroviruses. Gastroenteritis is not caused by bacteria. The main symptoms of gastroenteritis include vomiting and watery diarrhea, however, headache, fever, and abdominal cramps (stomach ache) may also be present.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Gastroenteritis is inflammation of the stomach, intestines, or both.
There are many causes of gastroenteritis; the most numerous cases are
caused by viruses, followed by bacteria and other agents.
The major gastroenteritis symptoms of diarrhea, nausea, vomiting, and
abdominal cramps; symptoms usually self-resolve in 2 to 5 days.
The majority of gastroenteritis disease is very contagious, especially
those caused by viruses and bacteria; a few causes of gastroenteritis are not
Gastroenteritis usually is not a serious illness unless the affected
dehydrated or an elderly person becomes infected with
especially, Clostridium difficile.
Most food, fluids, and other items become contaminated with causative agents of
gastroenteritis from direct or indirect contact with a person that has the
Most individuals have some risk of encountering gastroenteritis; people
that live in close contact with others (for example, live on a ship, in a dorm,
or barracks) have a higher risk.
People who become dehydrated should seek medical care; if the symptoms become
worse or are accompanied with other symptoms and/or last longer than about 5
days, the person should seek medical care as they may have a more
Gastroenteritis is frequently presumptively diagnosed by the symptoms;
infrequently, culture and identification, usually with immunological tests, of
the causative agent is done during large outbreaks of the disease.
Most people self-limit gastroenteritis in 2-5 days and require no
treatment as long as they remain well hydrated. IV hydration may be needed by
some people. Some clinicians treat the symptoms of nausea, vomiting, and diarrhea
with medications, others do not.
The major complication of gastroenteritis is dehydration; in addition,
pseudomembranous colitis may occur with Clostridium difficile
Hand washing, good hygiene, washing produce, cooking foods adequately, and
drinking only treated or pasteurized fluids can help prevent gastroenteritis.
The prognosis for gastroenteritis is usually excellent, unless dehydration
occurs or an elderly person's treatment is not started early in the infection.
(feces) is most commonly brown in color, and many people become curious or
concerned when the color of their stool changes. Most stool-to-stool changes in
color have little meaning; however, some "...