Stomach Flu (Tummy Bug) – Signs, Symptoms and Treatment

Infectious gastroenteritis is often referred to as a tummy bug or the stomach flu. It may be caused by bacteria, viruses or protozoa. The incubation period and duration of the infection may vary depending on the causative microorganism and the action of the microbe or toxins.

The signs and symptoms of acute gastroenteritis should be discernible from other gastrointestinal conditions like irritable bowel syndrome (IBS). Proper management is crucial and most of the time, treatment for acute infectious gastroenteritis is only necessary in prolonged cases or immunocompromised patients.

Refer to the article on Causes, Incubation Period and Duration of Infectious Gastroenteritis for further details on these aspects.

Signs and Symptoms of Gastroenteritis

The common signs and symptoms include :

  • Nausea
    • Constant and does not always ease after vomiting.
    • Retching is the involuntary but unproductive effort to vomit.
    • Heartburn and chest pain may be present as gastric contents rise up the esophagus coupled with muscle spasm from retching.
  • Vomiting
    • Severe with recurrent retching after expulsion.
    • May settle in the latter stages of the infection although nausea may still be present.
    • Eating solid foods usually aggravates nausea and vomiting.
    • Bloody vomit (hematemesis) is not always present and may only occur with persistent or violent vomiting (refer to gastritis caused by a Mallory-Weiss tear).
  • Diarrhea
    • Frequent, watery stools (large volume) often accompanied by intestinal cramps.
    • Certain infections and persistent diarrhea may result in bloody stools (melena ~ black, tarry; hematochezia ~ red, bloody).
    • Diarrhea may be mild in some infections.
    • Constant urging (tenesmus) may persist between evacuations.
  • Abdominal discomfort
    • Ranging from a dull ache,  to colicky or severe abdominal pain.
    • Bloating and tenderness often present, especially in bacterial infections.
  • Fever
    • Fever may be absent in some cases of infectious gastroenteritis – bacterial toxins may not cause a fever.
    • Other microorganism may cause a low, moderate or high fever.
    • Varies from >100F/37.7C to 104F/40C – temperatures in excess of 104F/40C requires immediate medical attention.
  • Dehydration
    • Complication of fluid loss – vomiting, diarrhea, perspiration.
    • May be moderate to severe and may lead to death if left untreated.
    • Dizziness, dry mouth, poor skin turgor and fainting.
    • Signs of shock due to severe dehydration – immediate medical attention necessary.

Treatment of Infectious Gastroenteritis

The focus should be on management – adequate rehydration, bed rest and gradual introduction to solid food. Acute infectious gastroenteritis should settle in 2 to 3 days in a healthy person. Medical treatment should be sought if the symptoms are persisting for more than 5 days or if there is any sign of moderate to severe dehydration.

  • Antibiotics may be necessary for treating infections caused by Vibrio cholerae, Shigella spp and salmenollosis. For other bacterial causes of gastroenteritis, antibiotics should be avoided unless a person is immunocompromised or in a case of persistent diarrhea where a stool culture confirms the bacterial species.
  • Antidiarrheal agents are not advisable in acute infectious gastroenteritis. The use of OTC (over-the-counter) antidiarrheal agents often results in complications especially if used excessively in a case of bacterial gastroenteritis.
  • Probiotics containing Saccharomyces boulardii and Lactobacillus casei GG may assist with persistent diarrhea following a case of acute infectious gastroenteritis. Probiotic use during the infection is of limited value. Live culture yogurt or dairy is unsuitable as this may aggravate the diarrhea (secondary lactose intolerance). Speak to a pharmacist about probiotics in capsule form.

Refer to the article on Oral Rehydration Therapy and BRAT Diet for the management of acute infectious gastroenteritis.

Related Articles

  1. Stomach Bug (Tummy Flu) – Causes, Incubation Period, Duration
  2. Oral Rehydration Therapy and BRAT Diet (Diarrhea, Vomiting)
  3. HIV Diarrhea Symptoms – Causes of Watery, Bloody Stool in AIDS
  4. Food Poisoning – Causes, Symptoms, Diagnosis, Treatment