Acute Gastroenteritis (Stomach flu)

Acute Gastroenteritis (also called Stomach Flu)

  • Acute gastroenteritis is a sudden condition that causes irritation and inflammation of the stomach and intestines or the gastrointestinal tract.
  • Viral infection is the most common cause of gastroenteritis but bacteria, parasites, and food-borne illness (such as shellfish) can also cause acute gastroenteritis.
  • Fifty to seventy percent of cases of gastroenteritis in adults are caused by the noroviruses while rotavirus is the leading cause of infection in children. Staphylococcus aureus can form a toxin that cause food poisoning while the resident Escherichia coli can also cause significant problems.
  • Many people who experience symptoms of vomiting and diarrhea, which develop from these types of infections or irritations believe they have food poisoning, and they indeed have a food-borne illness.
  • The severity of gastroenteritis depends on the immune system’s ability to resist and fight the infection. Electrolytes, especially sodium and potassium may be lost if the client continue to vomit and experience diarrhea.
  • Most people recover easily from a short course of vomiting and diarrhea by drinking lots of fluids and resuming a typical diet. But for some, especially the young and the old, loss of body fluids with gastroenteritis can cause dehydration, which is a life-threatening condition unless it is treated and fluids are replaced.


The mechanisms potentially responsible for viral diarrhea include lysis of enterocytes, interference with the brush border function that leads to malabsorption of electrolytes, stimulation of cyclic adenosine monophosphate (cAMP), and carbohydrate malabsorption. For bacterial gastroenteritis, the pathophysiology involves the elaboration of toxin by enterotoxigenic pathogens and the invasion and inflammation of mucosa by invasive pathogens. Parasitic organisms invade epithelial cells and cause villus atrophy and eventual malabsorption.

Clinical Manifestations:

  • Low grade fever to 100°F (37.8°C)
  • Nausea with or without vomiting
  • Mild to moderate diarrhea
  • Crampy and painful abdominal bloating

More serious symptoms include:

  • Blood in vomit or stool
  • Vomiting more than 48 hours
  • Fever higher than 101°F (40°C)
  • Swollen abdomen or abdominal pain
  • Dehydration that is manifested by weakness, lightheadedness, decreased and concentrated urination, dry skin and poor turgor, and dry lips and mouth

Diagnostic Tests:

  • Blood test
  • Analysis of stool samples
  • Electrolyte tests
  • Physical examination to rule other existing conditions such as appendicitis

Medical Management:

Home care:

  • Clear fluids are appropriate for the first 24 hours to maintain adequate hydration.
  • They should be given oral rehydration solutions such as Pedialyte for pediatric patients or commercially prepared oral rehydration solution.  For homemade ORS, mix 2 tablespoons of sugar (or honey) with ¼ teaspoon of table salt in 1 liter (1 qt) of clean or previously boiled water.
  • After 24 hours without vomiting , begin to offer soft bland foods such as the BRAT diet, which includes bananas, rice, applesauce without sugar, toast, pasta, and potatoes.


  • Hydration through intravenous line.
  • Replacement of fluid losses volume per volume.
  • Encourage small, frequent feedings.


  • Always wash your hands before eating and after using the comfort room.
  • Eat only properly cooked and stored food.
  • Bleach soiled linens used.
  • Have vaccinations for salmonella typhi, vibrio cholerae, and rotavirus.

Photo credits:

Daisy Jane Antipuesto RN MN

Currently a Nursing Local Board Examination Reviewer. Subjects handled are Pediatric, Obstetric and Psychiatric Nursing. Previous work experiences include: Clinical instructor/lecturer, clinical coordinator (Level II), caregiver instructor/lecturer, NC2 examination reviewer and staff/clinic nurse. Areas of specialization: Emergency room, Orthopedic Ward and Delivery Room. Also an IELTS passer.

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