What are the typical symptoms and signs of gastroenteritis?

Gastroenteritis Symptoms

Gastroenteritis typically presents with diarrhea (≥3 loose/liquid stools per 24 hours), often accompanied by vomiting, abdominal pain, and fever, with dehydration being the most clinically significant complication requiring assessment. 1

Core Clinical Presentations

The WHO defines diarrhea as passage of 3 or more loose or liquid stools per 24 hours, which forms the diagnostic cornerstone of gastroenteritis 1. The clinical syndrome manifests in several distinct patterns:

Primary Symptoms

• Diarrhea: Universal finding in all gastroenteritis cases, classified as either watery or bloody 1, 2

  • Acute watery diarrhea lasting <7 days is most common 1
  • Acute bloody diarrhea (dysentery) presents as frequent scant stools with blood and mucus 1

• Vomiting: Occurs in approximately 90.5% of cases, particularly prominent in viral gastroenteritis 3, 4

• Abdominal pain: Present in 13-100% of patients depending on pathogen and severity 3, 5

• Fever: Mild fever occurs in approximately 65.5% of cases 3, 4

Associated Findings

• Respiratory symptoms: Appear in approximately 60.7% of patients, particularly with rotavirus infection 3

• Nausea: Commonly accompanies vomiting and diarrhea 2, 5

Stool Characteristics

Macroscopic examination reveals important diagnostic clues:

• Mucus in stool: Found in approximately 46% of hospitalized patients 3
• Blood in stool: Present in 6.4% of cases, more common with bacterial pathogens and in immunocompromised patients 3, 2
• Acholic (pale) stool: Occurs in 8.4% of cases 3

Critical Complication: Dehydration

The most important clinical assessment involves evaluating hydration status, as dehydration drives morbidity and mortality. 4

Dehydration Assessment

Physical examination is the most reliable method for determining hydration status 4:

• Severe dehydration: Occurs in approximately 49.9% of hospitalized patients 3
• Metabolic acidosis: Develops in 79.2% of severe cases 3
• The four-item Clinical Dehydration Scale should be used to grade severity based on physical findings 4

Key Clinical Pitfall

Significant dehydration is unlikely if parents report no decrease in oral intake or urine output and no vomiting 4. However, physical examination remains superior to history alone for accurate assessment 4.

Temporal Classification

Duration of symptoms guides diagnostic and therapeutic approach 1:

• Acute: <7 days (most common presentation)
• Prolonged: 7-13 days
• Persistent: 14-29 days
• Chronic: ≥30 days

Age-Specific Considerations

• Children 7-24 months: Highest incidence of rotavirus gastroenteritis (71.8% of positive cases in this age group) 3
• Adults and elderly: Lower incidence but higher rates of hospitalization and mortality 1
• Infants <5 years: Highest disease incidence overall 1

Pathogen-Specific Patterns

While specific microbiological testing is not routinely needed for mild viral gastroenteritis 4, certain patterns emerge:

• Viral gastroenteritis (norovirus, rotavirus): Non-bloody diarrhea, prominent vomiting, affects both immunocompetent and immunocompromised patients 2
• Bacterial gastroenteritis: May present with bloody diarrhea, particularly with Shigella, Campylobacter, and STEC 1, 2
• Immunocompromised patients: Higher risk of bloody diarrhea from herpes virus and cytomegalovirus causing ulcerative GI disease 2

Disease Course

In hospitalized patients, illness duration averages 12.6 days with hospitalization averaging 10.2 days 3. Most cases in developed countries resolve without complications when appropriately managed 3.