Gastroenteritis is inflammation in the digestive system including the stomach, small and large intestines.It can be caused by viruses, bacteria, toxins, parasites, some chemicals and medications, although viruses are the leading cause.It is often called as the ‘stomach or intestinal flu,’ although it is not caused by the influenza viruses.


Symptoms of Gastroenteritis are as follows

Gastroenteritis is an acute illness that usually lasts between 1-2 days. However, symptoms may take 1-3 days to develop depending upon the causative agent and may range from slight discomfort to severe dehydration which can be fatal especially in children. The typical symptoms of the infection, irrespective of the cause include:

  • Diarrhea

  • Vomiting

  • Nausea

  • Abdominal cramps

  • Abdominal pain

  • Headache

  • Body ache

  • Chills

  • Bloating

  • Loss of appetite


Infectious gastroenteritis

Infections causing gastroenteritis can be viral, bacterial, or parasitic in origin.

  • Viruses: The most common viruses responsible for gastroenteritis are:

  • Norovirus: It is the most common cause and is responsible for most cases of viral gastroenteritis. The virus is mostly responsible for outbreaks within closed communities such as nursing homes, schools, military populations, athletic teams, and cruise ships.

  • Rotavirus: The virus is mostly responsible for severe vomiting in young children and infants. The infection of rotavirus in children and infants may require hospitalization.

Less common viruses that can cause gastroenteritis include astrovirus and adenovirus.


Gastroenteritis can also be caused by foods contaminated with chemicals such as lead, mercury, cadmium, and arsenic or by directly consuming a heavy metal or chemical.


Gastroenteritis can be a side effect of some medications such as :

  • Antacids containing magnesium as a major ingredient

  • Antibiotics

  • Chemotherapy drugs

  • Colchicine

  • Digoxin

  • Laxatives


Viral gastroenteritis is highly infectious. Viruses are present in the vomit and stool of the infected person and can live outside the human body for a long time. It can spread through:

  • Direct contact with vomit or stool of infected person

  • Shaking hands with infected person

  • Touching contaminated surfaces and objects such as handrails, elevator buttons, utensils, doors etc.

  • Sharing food and beverages with the infected person


  • Acute: The disease is considered as acute if the duration is 14 days or less than that.

  • Persistent: If the symptoms persist for 14-30 days, gastroenteritis is considered as persistent.

  • Chronic: The duration of more than 30 days makes the disease chronic in nature.

  • Recurrent: Gastroenteritis is considered chronic in nature if it recurs after 7 days without diarrhea.


Stool tests

The examination of the stool sample is done to diagnose bacteria and parasites in the stool. The test does not diagnose specific viral causes of gastroenteritis. Patients with bloody stool, high fever, severe abdominal pain, and chronic dehydration are usually recommended for stool tests due to their high specificity for bacterial gastroenteritis.

Examining the stool for blood

Blood in the stool can be a sign of infectious gastroenteritis. The stool sample is checked for the presence of hidden blood.

Stool culture

The culturing of the stool is done to identify the disease causing bacteria. For a stool culture, loose and fresh stool samples are taken. Sometimes, more than one stool samples are collected for the culture. The identification of the virus through stool culture can also be done, however it takes longer.

Testing the stool for parasites and ova

The presence of parasites and ova (the egg stage of the parasite) can also be detected in a stool sample. The identification is done by examining the stool smear under the microscope.

Blood tests

The complete blood count (CBC) is performed to check the infection. The infection can cause mild leukocytosis (high white blood cell count). In case of severe dehydration, electrolytes levels are also measured by blood tests.

Sometimes, serum inflammatory markers are also examined through blood tests.

Urine test

Dehydration can be due to acute kidney injury. Blood urea nitrogen and creatinine tests are also recommended to rule out the possibility of kidney disease.

Imaging tests

The imaging tests are rarely done for gastroenteritis. In some cases, imaging studies such as CT scans, ultrasound, and X-ray are done to diagnose the condition of the intestine. CT scans may show thickened walls of the colon or other inflammatory changes of the bowel. Imaging studies are mostly done to rule out other major causes of the symptoms.


Fluid therapy

  • Most cases of mild dehydration can easily be managed at home through fluid therapy.

  • It is advised to drink plenty of fluids to compensate for water loss and prevent dehydration.

  • Oral rehydration solutions are preferred over other clear fluids for managing diarrhea.

  • Fluids high in sugar (such as cola, apple juice, and sports drink) should be avoided as they may aggravate dehydration and diarrhea.

  • Patients having severe dehydration and persistent vomiting may require hospital admission for continuous monitoring of electrolyte level.

  • Enteral (oral or nasogastric) and intravenous fluids (Saline solution and lactate Ringer’s solutions) are given to patients facing difficulty in taking fluids due to nausea, vomiting, and to correct electrolyte levels.

Zinc supplementation

  • Zinc is a metal that is found in a variety of foods such as meat, fish, almonds, and cereals. Diarrhea, the most common symptom of gastroenteritis, is associated with severe zinc deficiency.

  • Zinc supplementation is a very safe and effective way for reducing complications due to gastroenteritis in children. WHO recommends the intake of 10 to 20 mg of zinc for 10 to 14 days for the management of diarrhea in children.

  • It is given in the form of zinc sulfate, zinc acetate, or zinc gluconate.


Probiotics are effective in the treatment of diarrhea, especially for diseases with an infectious origin. The use of probiotics is associated with the reduction in the duration of the diarrhea, if started immediately after the onset of symptoms.


They are mostly used to treat gastroenteritis caused by bacteria. Some of the commonly used antibiotics in gastroenteritis include metronidazole, ceftriaxone, and azithromycin.


Antiemetic medications are the drugs that are used to control nausea and vomiting. The commonly used antiemetic medications are ondansetron and metoclopramide.

Antidiarrheal medications

Antidiarrheal medications are used only in those patients who are not able to maintain a well-hydrated status. Medications such as diphenoxylate, atropine are used.

diseases treatments health prevention gastroenteritis digestive-system disorders

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