What is Gastroenteritis? Causes, Symptoms, Diagnosis, Treatment, and Complications

Gastroenteritis refers to inflammation of the stomach and intestines. Patients with this condition typically experience stomachache, diarrhea, and vomiting. In most cases, the condition is self-limiting and resolves completely within a few days without any need for medical intervention.

Causes of gastroenteritis

Gastroenteritis may be caused by a virus, bacterium, or parasite. The most common cause is a virus, especially the norovirus, rotavirus, and adenovirus.

According to the World Health Organization:

“Norovirus is a viral illness that is the most common cause of acute gastroenteritis globally. An estimated 685 million cases of norovirus are seen annually, including 200 million cases amongst children under 5.”

“Norovirus causes an estimated 200,000 deaths per year, including 50,000 child deaths, primarily impacting low-income countries. It has been estimated to cost $60 billion globally as a result of healthcare costs and economic losses.”

When the cause is bacterial, symptoms can be severe. Examples include Salmonella, Escherichia coli (E. coli), and Campylobacter.

The most common parasites that cause inflammation of the stomach and intestines are Giardia and Cryptosporidium. This type can be more severe than either bacterial or viral infections.

Signs and symptoms

If you experience something that only you can detect, such as a headache or suicidal thoughts, it is a symptom. If you have a skin rash, which both you and other people can detect, it is a sign.

The most common signs and symptoms of gastroenteritis are:

  • Diarrhea.
  • Dehydration due to loss of fluids from vomiting and diarrhea.
  • Nausea, feeling queasy, i.e., having an urge to vomit (you feel like throwing up).
  • Vomiting, which often overcomes the patient suddenly with a forceful explosion of stomach contents.
  • Stomachache, discomfort or cramping in the abdomen.
  • Fever – temperature of at least 100.4°F (38°C).

Diagnosis of gastroenteritis

The doctor’s diagnosis is the result of identifying specific signs and symptoms. They will also perform a physical exam and check the patient’s medical history.

Less commonly, the doctor may order stool tests, imaging tests, and blood tests to rule out other illnesses or conditions with similar symptoms.

Gastroenteritis Viruses

Wikipedia image adapted by medicalvocab.com


Treatment depends on the cause of the inflammation. As mentioned earlier, in most cases no treatment is required because the condition resolves on its own within a few days.

If treatment is necessary, it most likely includes:

  • Rehydration – the patient drinks water, sports drinks, clear broths, and other liquids to help replace lost fluids and electrolytes.
  • Rest – as with many illnesses, lots of rest and avoiding strenuous physical activity helps the body recover faster.
  • Drugs – OTC medications such as bismuth subsalicylate (Pepto-Bismol) and loperamide (Imodium) can help treat stomach cramps and diarrhea. OTC stands for over the counter. Over the counter medications do not require a doctor’s prescription.
  • Antibiotics are only effective if the gastroenteritis is caused by bacteria.


In extreme cases, gastroenteritis can lead to severe dehydration, electrolyte imbalances, and malnutrition.

Bacterial infections can, in very rare cases, lead to reactive arthritis, and kidney failure, and sepsis. Sepsis refers to a current infection which spreads and triggers a chain reaction through the patient’s body.

Seniors, people with weakened immune systems, young children, and infants are more vulnerable to complications than the rest of the population.

If you, a family member, or a friend experience severe signs and symptoms, such as dizziness, dry mouth, and rapid heartbeat (triggered to extreme dehydration), see your doctor immediately.

Regarding the difference between dysentery and gastroenteritis, healthline.com says the following:

“Dysentery is a form of gastroenteritis. You can think of gastroenteritis as the umbrella term while dysentery is more specific.”

“Dysentery is an intestinal infection that causes severe diarrhea with blood or sometimes mucus present in the stool. It may sound like a disease from long ago, but dysentery is actually still around — there are about half a million casesTrusted Source in the United States per year.”

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