Viral Gastroenteritis Clinical Presentation

Updated: Jan 08, 2018
  • Author: Brian Lin; Chief Editor: Burt Cagir, MD, FACS  more...
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The clinical spectrum of acute viral gastroenteritis ranges from asymptomatic infection to severe dehydration and death. Viral gastroenteritis typically presents with short prodrome, with mild fever and vomiting, followed by 1-4 days of nonbloody, watery diarrhea. Viral gastroenteritis is usually self-limited.

  • The history should focus on severity and dehydration. The onset, frequency, quantity, and duration of diarrhea and vomiting are important factors in assessing the status. Oral intake, urine output, and weight loss are important considerations. Viruses are the suspected cause of acute gastroenteritis when vomiting is prominent, when the incubation period is longer than 14 hours, and when the entire illness is over in less than 3 days. Travel history (including cruise ships), eating history, and daycare history are important epidemiological factors.

  • A viral cause should be suspected when the warning signs of bacterial infection (ie, high fever, bloody diarrhea, severe abdominal pain, >6 stools/24 h) are absent and an alternative diagnosis is not suggested by epidemiologic clues from the history (eg, travel, sexual practices, antibiotic use).

  • Factors associated with severe and prolonged disease are immunodeficiency and immune suppression, comorbid disease, and malnutrition.

  • Death results from dehydration and acidosis.

  • Ruling out other diagnoses is important. Mucus or overt blood in the stool almost always indicates bacterial or parasitic infection.

In 1982, the Kaplan criteria were established to distinguish outbreaks due to norovirus from outbreaks of bacterial etiology. The criteria are highly specific (99%) and moderately sensitive (68%). The 4 criteria indicative of an outbreak due to norovirus are as follows: [23]

  • Vomiting in 50% of affected persons in the outbreak

  • Mean incubation period of 24-48 hours

  • Mean duration of illness of 12-60 hours

  • Lack of identification of a bacterial pathogen in stool culture


Physical Examination

The physical examination can be helpful in determining the etiology of gastroenteritis and in assessing the presence and degree of dehydration.

  • Temperature, blood pressure and pulse, and body weight can provide evidence of severity of the condition.

  • Temperature may be slightly elevated. High fever suggests bacterial infection. Tachycardia, thready pulse, and hypotension suggest severe dehydration.

  • Inflammatory signs associated with bowel infection (fever, bloody or mucoid stools) suggest invasive bacteria (eg, salmonella, shigella, or campylobacter), enteric viruses (eg, cytomegalovirus [CMV] or adenovirus), Entamoeba histolytica, or a cytotoxic organism such as C difficile. [24]

  • The degree of weight loss may be related to dehydration and the duration of the diarrhea.

  • The mucous membranes and the skin should be examined carefully. Dry mouth, no tears, skin tenting, dry skin, and capillary refill are all signs of dehydration.

  • The mental status in elderly patients and infants may be abnormal, especially when blood pressure and circulation are compromised.

  • The abdominal examination may demonstrate mild tenderness. Severe abdominal pain and tenderness suggest bacterial infection or an abdominal emergency.