What are the signs and symptoms of viral gastroenteritis?

Signs and Symptoms of Viral Gastroenteritis

Viral gastroenteritis primarily presents with nausea, vomiting, non-bloody diarrhea, and abdominal cramps, with symptoms typically lasting 1-7 days depending on the causative virus. 1

Common Symptoms by Frequency

Based on studies of viral gastroenteritis outbreaks, the most common symptoms include:

• Gastrointestinal symptoms:

  • Nausea (79%)
  • Abdominal cramps (71%)
  • Vomiting (69%)
  • Diarrhea - always non-bloody (66%)

• Systemic symptoms:

  • Headache (50%)
  • Fever (37%)
  • Chills (32%)
  • Muscle aches/myalgias (26%)
  • Sore throat (18%) 1

Symptom Patterns by Age Group

The presentation varies by age group:

• Children:

  • Higher proportion experience vomiting
  • May have respiratory symptoms (especially with adenovirus)
  • Dehydration develops more rapidly than in adults 1, 2

• Adults:

  • Higher proportion experience diarrhea
  • More likely to report headache and myalgias
  • Elderly may have prolonged constitutional symptoms for several weeks 1

Characteristics by Common Viral Pathogens

Norwalk-like Viruses (Noroviruses)

• Incubation period: 24-48 hours
• Duration: 12-60 hours
• Prominent nausea with vomiting
• Non-bloody diarrhea
• Abdominal cramps
• Affects all age groups but more common in school-age children and adults 1

Rotavirus

• Primarily affects children under 5 years
• Incubation period: 1-3 days
• Duration: 5-7 days
• Watery diarrhea
• Vomiting and fever common
• Can cause severe dehydration 1, 3

Adenovirus (enteric types 40 and 41)

• Incubation period: 3-10 days
• Duration: ≥1 week (longer than other viral pathogens)
• Diarrhea more prominent than vomiting
• Often accompanied by respiratory symptoms
• Primarily affects children 1

Astrovirus

• Incubation period: 24-36 hours
• Duration: 1-4 days
• Affects mainly children <7 years and elderly
• Vomiting, diarrhea, fever, and abdominal pain 1

Calicivirus

• Incubation period: 1-3 days
• Duration: average 4 days
• Vomiting and diarrhea common
• Upper respiratory symptoms and fever less frequent 1

Warning Signs of Severe Disease

• Signs of dehydration (decreased urination, dry mouth, sunken eyes, lethargy)
• Persistent vomiting preventing oral rehydration
• Bloody diarrhea (suggests bacterial rather than viral etiology)
• High fever (>101.5°F/38.5°C)
• Severe abdominal pain
• Symptoms persisting beyond 7 days 2, 4

Key Diagnostic Features

• Temporal pattern: Acute onset with self-limited course (typically 1-7 days)
• Stool characteristics: Watery, non-bloody diarrhea
• Associated symptoms: Combination of gastrointestinal and systemic symptoms
• Epidemiological context: Often occurs in outbreaks in closed settings (nursing homes, cruise ships, schools) 1

Common Pitfalls in Diagnosis

1. Failure to recognize dehydration: Particularly dangerous in very young children and elderly patients
2. Misdiagnosis as bacterial gastroenteritis: Viral gastroenteritis never presents with bloody diarrhea
3. Overlooking viral gastroenteritis in adults: Often dismissed as "food poisoning" without proper evaluation
4. Unnecessary antibiotic use: Antibiotics are ineffective against viral pathogens and may worsen outcomes by disrupting gut flora 1, 2

Viral gastroenteritis is typically self-limited, with management focused on preventing dehydration through oral rehydration therapy and supportive care while the infection runs its course 4.