Gastroenteritis is a medical condition affecting the stomach and small bowel presenting mainly with loose motion. It occurs mainly due to bacterial, viral or parasitic infections. The spread of infection usually occurs from person-to-person and via contaminated food and water. It is a common infection that is self limiting, meaning that it passes in a few days often without the need for any treatment measures. The main treatment for gastroenteritis is prevention of dehydration by adequate fluid replacement and medication if required.


Gastroenteritis due to different causes usually produces more or less common set of symptoms, namely :

  • Diarrhea may be associated with passage of blood (dysentery), usually in bacterial infection.
  • Nausea and sometimes vomiting.
  • Abdominal cramping.
  • Fever.
  • Loss of appetite.
  • Loud bowel sounds (borborygmi).

Sometimes associated symptoms of dehydration (due to fluid and electrolyte loss) may also be present :

  • Drying of mouth and eyes.
  • Loss of skin elasticity.
  • Increased thirst.
  • Fatigue and lethargy.
  • Muscle weakness and cramps.
  • Headaches.

There are typical symptoms associated with infection with particular pathogen, like :

  • Joint pain (reactive arthritis) and weakness starting from limbs progressing to trunk (Guillain-Barre syndrome) with infection by Campylobacter and some viruses.
  • Kidney damage, abnormal clotting of blood due increased breakdown of platelets and severe anemia due to increased breakdown of RBC known as hemolytic-uremic syndrome (HUS) may occur due to infection with particular strain of E.coli and Shigella.
  • Epileptic fits (seizure) may be associated with some viral infections.


The cause of gastroenteritis may be of following types :

Bacterial infection by:

  • Campylobacter
  • E.coli
  • Salmonella
  • Shigella

Bacterial infection usually occurs due to intake of contaminated food or water or droplet spread from person-to-person.

Contaminated foods are may include :

  • Uncooked meat, egg, sea food
  • Unpasteurized milk and milk products.
  • Raw vegetables and fruits not properly washed.
  • Cooking in contaminated utensils.
  • Poor maintenance of personal hygiene and poor sanitary system facilitate in spreading of the disease.
  • Viral infection also spreads in the same way as bacterial infection.

Commonly infecting viruses are :

  • Norovirus commonly infects school going children.
  • Rotavirus: young children are most commonly affected but even adults may also be affected usually from infected children.
  • Adenovirus and astrovirus.

Parasitic infections caused by :

  • Giardia
  • Entamoeba
  • Cryptosporidium

Parasitic gastroenteritis most commonly affects people in developing countries. There may be some non-infectious medical condition which may cause gastroenteritis such as :

  • Lactose intolerance
  • Celiac disease (intolerance to gluten)
  • Crohn’s disease

Risk factors

  • Poor sanitary conditions.
  • Poor maintenance of personal hygiene.
  • Drinking of contaminated water.
  • Consumption of undercooked meat, uncooked raw vegetables, unpasteurized milk and milk products.


All viral and most bacterial gastroenteritis cases are self-limiting  and usually resolves without any treatment. The primary goal of treatment is prevention of dehydration by using oral rehydration solution. In a few cases there is severe dehydration, unconsciousness and profuse vomiting in which case parenteral (intravenous) fluid replacement is recommended

Breastfeeding must not be discontinued in gastroenteritis and a proper diet is essential in children as there is risk of development of malnutrition in children suffering from gastroenteritis. Zinc supplementation has been found to be beneficial. Antibiotics usually not required, may be given in severe cases. Sometimes antimotility agents are prescribed to reduce frequency of diarrhea. Anti-diarrheal drugs should be avoided as far as possible as it stops the body’s attempts to flush out the infecting organisms, its toxins and other irritants in the bowel.


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