Pediatric Gastroenteritis

Quick Reference Card

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Overview

Acute gastroenteritis (AGE) is an infection of the gastrointestinal tract characterized by the acute onset of diarrhea, with or without vomiting, fever, and abdominal pain. [1] It represents one of the most common childhood illnesses worldwide and remains a leading cause of morbidity in developed countries and mortality in resource-limited settings. The World Health Organization estimates that diarrheal diseases cause approximately 525,000 deaths annually in children under 5 years globally, representing 8% of all deaths in this age group. [2]

In high-income countries, acute gastroenteritis remains the second most common infectious disease after respiratory infections, causing significant healthcare burden. [3] The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and European Society for Paediatric Infectious Diseases (ESPID) guidelines emphasize that the primary therapeutic intervention is prevention and treatment of dehydration through oral rehydration therapy, with intravenous fluids reserved for severe cases or oral rehydration failure. [1]

The introduction of rotavirus vaccination has dramatically reduced the burden of severe gastroenteritis requiring hospitalization in countries with high vaccine coverage, though norovirus has now emerged as the leading cause of medically-attended acute gastroenteritis in children. [4] Understanding the etiology, accurate assessment of dehydration severity, and evidence-based management remain essential skills for all clinicians caring for children.

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Epidemiology

Global Burden

Acute gastroenteritis accounts for an estimated 1.7 billion episodes of diarrhea annually in children under 5 years worldwide. [2] The burden differs substantially between high-income and low-income settings:

Developed Country Statistics

In the United States, acute gastroenteritis accounts for approximately 1.5 million outpatient visits, 200,000 hospitalizations, and 300 deaths annually in children under 5 years. [5] Emergency department visits for pediatric gastroenteritis occur at a rate of approximately 3-5 per 100 children annually. [3]

Exam Detail: ### Age-Specific Epidemiology

The peak incidence of acute gastroenteritis occurs in children aged 6-24 months, corresponding to:

• Waning maternal antibody protection
• Introduction of complementary foods
• Increased oral exploration behavior
• Early daycare exposure
• Incomplete vaccine coverage

Seasonal Patterns:

Impact of Rotavirus Vaccination

The introduction of rotavirus vaccines has dramatically changed the epidemiology of severe gastroenteritis. A systematic review of post-licensure studies demonstrated:

• 49-89% reduction in rotavirus hospitalizations in high-income countries [6]
• 40-59% reduction in all-cause gastroenteritis hospitalizations [6]
• Shift in peak age from 6-24 months to 2-5 years in some populations
• Herd immunity effects observed in unvaccinated populations

Following widespread rotavirus vaccination, norovirus has emerged as the leading cause of medically-attended acute gastroenteritis in US children, responsible for approximately 1 million healthcare visits annually. [4]

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Etiology

Viral Pathogens (70-80% of Cases)

Viruses are the predominant cause of acute gastroenteritis in children, particularly in high-income settings. The four major viral pathogens demonstrate distinct epidemiological and clinical characteristics:

Rotavirus

Rotavirus remains the most common cause of severe gastroenteritis requiring hospitalization globally, though its incidence has declined dramatically in countries with high vaccine uptake. [6]

Clinical Pearl: Rotavirus Clinical Pearl: Rotavirus typically causes more severe vomiting early in the illness compared to other pathogens, often preceding diarrhea by 24-48 hours. The combination of profuse watery diarrhea and early vomiting leads to rapid dehydration, explaining why rotavirus historically caused the most hospitalizations before widespread vaccination.

Norovirus

Norovirus has become the leading cause of medically-attended gastroenteritis in countries with high rotavirus vaccine coverage. [4] It demonstrates unique epidemiological features:

Exam Detail: Norovirus Outbreak Characteristics:

• Very high attack rate (50-70% of exposed individuals)
• Rapid spread through families, daycare, hospitals, cruise ships
• Resistance to alcohol-based hand sanitizers (non-enveloped virus)
• Requires soap and water handwashing for effective decontamination
• Chlorine-based disinfectants required for environmental cleaning

Adenovirus (Enteric Types 40/41)

Enteric adenoviruses cause approximately 5-10% of pediatric gastroenteritis cases with distinct clinical features:

Other Viral Pathogens

Bacterial Pathogens (10-20% of Cases)

Bacterial gastroenteritis tends to cause more severe illness with bloody diarrhea (dysentery) and is more common in summer months. [7]

Salmonella (Non-typhoidal)

Clinical Pearl: Salmonella Pearl: Antibiotic treatment is NOT indicated for uncomplicated Salmonella gastroenteritis in immunocompetent children > 3 months, as antibiotics may prolong the carrier state without shortening illness duration. Antibiotics ARE indicated for infants less than 3 months, immunocompromised patients, bacteremia, or severe illness.

Campylobacter

Shigella

Exam Detail: ### Shigella Toxins and Pathogenesis

Shigella produces several virulence factors:

1. Invasion plasmid antigens (Ipa): Enable epithelial cell invasion
2. Shiga toxin (S. dysenteriae type 1): Cytotoxic, causes HUS
3. Inflammatory response: Intense neutrophil infiltration causes bloody mucoid stools

Key distinguishing feature: Shigella invades colonic epithelium causing intense inflammation with WBCs in stool, unlike ETEC which produces secretory diarrhea without invasion.

Shiga Toxin-Producing Escherichia coli (STEC)

Clinical Pearl: STEC Red Flag: The classic STEC presentation is severe abdominal pain with bloody diarrhea but MINIMAL OR NO FEVER. The absence of fever in a child with bloody diarrhea should raise suspicion for STEC. Antibiotics are CONTRAINDICATED as they may increase the risk of HUS by promoting toxin release. [8]

Other Bacterial Pathogens

Parasitic Pathogens (5-10% of Cases)

Parasitic gastroenteritis is characterized by prolonged symptoms and is associated with travel, daycare outbreaks, and contaminated water sources:

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Pathophysiology

Mechanisms of Diarrhea

Understanding the pathophysiological mechanisms helps predict clinical features and guide management:

Secretory Diarrhea

The hallmark of toxin-producing pathogens (cholera, ETEC, rotavirus):

1. Toxin binding: Enterotoxin binds to epithelial cell receptors
2. Cyclic nucleotide activation: Increased cAMP (cholera toxin) or cGMP (STa toxin)
3. Ion channel dysregulation:
   • Increased chloride secretion via CFTR channels
   • Decreased sodium and water absorption
4. Osmotic gradient: Water follows electrolytes into intestinal lumen
5. Result: Profuse watery diarrhea, no mucosal damage

Exam Detail: ### Rotavirus Pathophysiology

Rotavirus causes diarrhea through multiple mechanisms: [9]

1. NSP4 enterotoxin: First viral enterotoxin discovered

   • Increases intracellular calcium
   • Activates calcium-dependent chloride channels
   • Causes secretory diarrhea

2. Villous damage:

   • Preferentially infects mature enterocytes at villous tips
   • Causes villous blunting and crypt hyperplasia
   • Reduces absorptive surface area

3. Enzyme deficiency:

   • Damage to brush border enzymes (lactase, sucrase)
   • Temporary lactose malabsorption
   • Osmotic diarrhea component

4. Enteric nervous system activation:

   • Stimulates secretion via VIP and serotonin pathways
   • Increases intestinal motility

Inflammatory/Invasive Diarrhea

The mechanism in Shigella, Salmonella, Campylobacter, and invasive E. coli:

1. Epithelial invasion: Bacteria penetrate M cells or enterocytes
2. Intracellular replication: Multiplication within epithelial cells
3. Inflammatory cascade:
   • IL-8 release recruits neutrophils
   • Cytokine storm (IL-1, TNF-α)
   • Prostaglandin-mediated secretion
4. Mucosal damage: Ulceration, hemorrhage, protein loss
5. Result: Bloody mucoid diarrhea, fever, tenesmus

Osmotic Diarrhea

Occurs when malabsorbed substances draw water into the intestinal lumen:

• Mechanism: Unabsorbed solutes create osmotic gradient
• Causes: Lactase deficiency (post-viral), excessive fruit juice intake, malabsorption syndromes
• Characteristic: Stops with fasting or removal of offending substance
• Clinical relevance: Avoid high-sugar drinks during gastroenteritis (osmotic worsening)

Dehydration Pathophysiology

Children are more vulnerable to dehydration than adults due to: [10]

Exam Detail: ### Electrolyte Disturbances in Gastroenteritis

Sodium Abnormalities:

• Isonatremic dehydration (most common, ~80%): Proportionate loss of sodium and water
• Hyponatremic dehydration (~15%): Excess free water replacement (dilute fluids)
• Hypernatremic dehydration (~5%): Inadequate water replacement or hyperosmolar feeds

Potassium:

• Total body potassium depletion common
• Serum K+ may be normal initially (acidosis shifts K+ extracellularly)
• Hypokalemia may manifest during rehydration

Acid-Base:

• Metabolic acidosis from:
  • Bicarbonate loss in stool
  • Lactic acidosis (hypoperfusion)
  • Ketosis (poor intake)
• Elevated anion gap suggests more severe illness

Glucose:

• Hypoglycemia risk in young infants (limited glycogen stores)
• Hyperglycemia possible with stress response

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Clinical Presentation

Symptoms

Typical Presentation

The classic triad of acute gastroenteritis includes diarrhea, vomiting, and fever, though not all components are always present:

Symptom Duration

History Taking

A systematic history helps assess severity, identify etiology, and exclude alternative diagnoses:

Essential History Components

Illness Characterization:

• Onset: Sudden (viral, toxin) vs gradual (parasitic)
• Duration of symptoms
• Frequency: Stool count/day, vomiting episodes
• Stool character: Watery, mucoid, bloody, color
• Vomit character: Bilious (GREEN = emergency), bloody, undigested food

Hydration Assessment:

• Oral intake: Volume and type of fluids tolerated
• Output: Wet diapers (number in 24 hours), urine color
• Last urination time
• Tears when crying
• Activity level compared to baseline

Risk Factor Evaluation:

• Sick contacts (household, daycare)
• Recent travel (domestic and international)
• Food history: Undercooked meat, unpasteurized products, restaurant exposure
• Water exposure: Swimming, well water
• Animal exposure: Reptiles, farm animals, pets
• Recent antibiotics (C. difficile risk)
• Immunization status (rotavirus)

Medical History:

• Age (infants less than 3 months at higher risk)
• Immunocompromised status
• Chronic diseases (diabetes, renal, cardiac)
• Prior surgeries (short gut, ostomy)

Physical Examination

Dehydration Assessment

Accurate assessment of dehydration severity is the most critical component of the physical examination and drives management decisions. [1,11]

WHO/ESPGHAN Dehydration Classification:

Clinical Pearl: Dehydration Assessment Pearl: The most reliable individual clinical signs for detecting dehydration are: prolonged capillary refill time, abnormal skin turgor, and abnormal respiratory pattern. The combination of multiple signs improves diagnostic accuracy. [11]

No single sign is sufficiently sensitive or specific to reliably detect or exclude dehydration. A clinical dehydration scale (CDS) combining multiple signs performs better than individual assessments.

Clinical Dehydration Scale (CDS)

A validated 4-item scale for children 1 month to 5 years: [12]

Score Interpretation:

• 0: No dehydration
• 1-4: Some dehydration
• 5-8: Moderate-severe dehydration

Abdominal Examination

Essential to exclude surgical pathology:

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Red Flags and Differential Diagnosis

Red Flags Requiring Urgent Evaluation

Differential Diagnosis

Not all vomiting and diarrhea is gastroenteritis. A systematic approach excludes dangerous mimics:

Surgical Emergencies

Clinical Pearl: Intussusception Pearl: The classic triad (colicky pain, vomiting, currant jelly stool) is present in only 20-40% of cases. Lethargy may be the only presenting sign in young infants. Any infant with unexplained lethargy should have intussusception considered.

Medical Conditions Mimicking Gastroenteritis

Chronic/Recurrent Causes

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Investigations

General Principles

Acute gastroenteritis is primarily a clinical diagnosis. Laboratory investigations are not routinely required for uncomplicated cases and should be guided by clinical severity and specific indications. [1]

Clinical Pearl: Investigation Pearl: For the typical well-appearing child with mild-moderate gastroenteritis, NO laboratory tests are needed. Focus clinical time on accurate dehydration assessment and oral rehydration rather than ordering unnecessary tests.

Indications for Laboratory Testing

Stool Studies

Stool Culture

Indications:

• Bloody diarrhea
• High fever with toxic appearance
• Immunocompromised host
• Prolonged diarrhea (> 7 days)
• Recent travel
• Outbreak investigation

Pathogens detected: Salmonella, Shigella, Campylobacter, STEC (requires specific request at many labs)

Exam Detail: Stool Culture Yield:

• Only 2-6% of routine stool cultures are positive in developed countries
• Higher yield with bloody diarrhea, fever, and specific risk factors
• STEC detection requires sorbitol-MacConkey agar or PCR (specify on order)
• Campylobacter requires selective media and incubation conditions

Stool Ova and Parasites

Indications:

• Prolonged diarrhea (> 14 days)
• Travel to endemic areas
• Daycare outbreaks
• Immunocompromised
• Freshwater exposure

Note: Often requires 3 specimens on different days for adequate sensitivity

C. difficile Testing

Indications:

• Recent antibiotic use (within 8 weeks)
• Healthcare-associated exposure
• Recurrent symptoms

Testing approach:

• Toxin EIA: Rapid, lower sensitivity
• PCR: High sensitivity, may detect colonization
• Two-step algorithm (GDH + toxin) preferred in many labs

Viral Studies

Generally not clinically necessary as management is unchanged

• May be useful for outbreak investigation
• Rotavirus antigen testing available
• Norovirus PCR for public health purposes

Blood Tests

Imaging

Not routinely indicated for uncomplicated gastroenteritis

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Management

Overview of Management Principles

The ESPGHAN/ESPID guidelines emphasize the following hierarchy of management: [1]

1. Assess and treat dehydration - The primary therapeutic goal
2. Continue feeding - Early refeeding shortens illness duration
3. Avoid unnecessary medications - Most antiemetics and antidiarrheals not recommended
4. Selective use of adjunctive therapies - Ondansetron, zinc, probiotics in specific situations
5. Antibiotics only when indicated - Minority of cases

Oral Rehydration Therapy (ORT)

Oral rehydration therapy is the cornerstone of gastroenteritis management and represents one of the most important medical advances of the 20th century. [13]

Physiological Basis

ORT exploits the coupled sodium-glucose transport mechanism (SGLT1) in the small intestine, which remains intact during most diarrheal illnesses:

• Glucose absorption drives sodium absorption
• Water follows sodium osmotically
• This mechanism is preserved even when other transport mechanisms are impaired

Exam Detail: ### ORS Composition

WHO/UNICEF Low-Osmolarity ORS (Recommended):

Rationale for Low-Osmolarity ORS: A Cochrane systematic review demonstrated that reduced osmolarity ORS (245 mOsm/L) compared to standard WHO-ORS (311 mOsm/L) results in: [14]

• 33% reduction in unscheduled IV therapy
• 20% reduction in stool output
• 30% reduction in vomiting

Commercial ORS Solutions:

NOT Recommended:

• Fruit juices (high osmolarity, low sodium)
• Sports drinks (high osmolarity, low sodium)
• Soda/soft drinks (no electrolytes, high sugar)
• Water alone (may cause hyponatremia)

ORT Protocol by Dehydration Severity

No Dehydration (Prevention):

• Continue breastfeeding on demand
• Offer ORS after each loose stool:
  • "Children less than 2 years: 50-100 mL"
  • "Children 2-10 years: 100-200 mL"
  • "Older children: Ad libitum"
• Continue age-appropriate diet

Some Dehydration (3-8%):

Administration Technique:

• Small, frequent volumes (5-10 mL every 1-2 minutes)
• Use syringe, spoon, or cup (not bottle)
• Increase volume as tolerated
• If vomiting occurs, wait 10 minutes, then restart smaller volumes
• Goal: Complete deficit replacement over 4 hours

Clinical Pearl: ORT Success Tips:

1. Small and slow: 5 mL every minute is 300 mL/hour
2. Cold ORS: Often better tolerated
3. Flavor: Plain is best; avoid adding sugar
4. Persistence: Mild vomiting is not a contraindication
5. Parental confidence: Education is key to home success

Ondansetron for Vomiting

Ondansetron significantly improves oral rehydration success and reduces the need for IV fluids: [15]

Indications:

• Persistent vomiting preventing oral rehydration
• Moderate dehydration with vomiting

Dosing:

Evidence: A landmark randomized controlled trial demonstrated that a single dose of oral ondansetron in children with vomiting and dehydration resulted in: [15]

• Decreased vomiting episodes (mean 0.18 vs 0.65 episodes)
• Increased oral intake
• Reduced IV fluid administration (14% vs 31%)
• Reduced hospitalization

Precautions:

• May cause mild increase in diarrhea (clinically insignificant)
• QT prolongation (rare at single antiemetic doses)
• Avoid in congenital long QT syndrome

Intravenous Fluid Therapy

Indications for IV Fluids

Fluid Choice

Current Evidence-Based Recommendations:

Exam Detail: ### Rapid vs Traditional Rehydration

Traditional approach: Replace deficit over 24-48 hours Rapid rehydration: Replace deficit over 4 hours

Evidence from multiple studies supports rapid rehydration (4-hour deficit replacement) with isotonic fluids: [16]

• Equally safe as prolonged rehydration
• Shorter ED/hospital stays
• Earlier return to oral intake
• No increased adverse events

Rapid Rehydration Protocol:

1. Bolus 20 mL/kg NS if signs of poor perfusion
2. Calculate deficit: Weight × % dehydration × 10 = mL deficit
3. Administer deficit over 4 hours
4. Reassess and transition to oral when tolerated
5. Replace ongoing losses: 10 mL/kg per stool/vomit

Isotonic vs Hypotonic Maintenance Fluids

Historical practice used hypotonic maintenance fluids (e.g., D5 0.2% NS), but this increases risk of hospital-acquired hyponatremia. Current guidelines recommend isotonic maintenance fluids for most hospitalized children.

IV Fluid Protocol for Severe Dehydration/Shock

Initial Resuscitation:

1. Establish IV/IO access (don't delay for IV if needed)
2. Bolus: 20 mL/kg 0.9% NS over 10-20 minutes
3. Reassess (HR, BP, cap refill, mental status)
4. Repeat bolus up to 60 mL/kg total if still compromised
5. If > 60 mL/kg required, consider other causes (sepsis, hemorrhage)

Post-Resuscitation:

1. Calculate remaining deficit
2. Continue isotonic fluids to replace deficit over 4 hours
3. Add maintenance requirements
4. Monitor urine output (target > 1 mL/kg/hour)
5. Transition to oral when mental status and vomiting improved

Nutrition and Feeding

Key Principles

Early refeeding is safe and beneficial: [1,17]

1. Continue breastfeeding: Never stop breastfeeding during gastroenteritis
2. Resume formula: Full-strength formula within 4-6 hours of rehydration
3. Age-appropriate diet: Resume regular diet once rehydrated
4. No dietary restrictions: BRAT diet (bananas, rice, applesauce, toast) is no longer specifically recommended
5. Avoid high-sugar foods/drinks: May worsen osmotic diarrhea

Lactose-Free Formula

Routine use NOT recommended

Consider temporary lactose-free formula if:

• Prolonged diarrhea (> 7 days)
• Symptoms worsen with reintroduction of lactose-containing feeds
• Clinical suspicion of secondary lactose intolerance

Duration: 2-4 weeks typically sufficient for recovery of lactase activity

Zinc Supplementation

The WHO and UNICEF recommend zinc supplementation for children with diarrhea in developing countries: [18]

Evidence: A Cochrane review of 33 trials demonstrated that zinc supplementation: [18]

• Reduces diarrhea duration by ~12 hours
• Reduces stool frequency
• Reduces treatment failure and hospitalization
• Greatest benefit in zinc-deficient populations

Developed country recommendations:

• Not routinely recommended in well-nourished children
• May be considered for children with malnutrition or zinc deficiency

Probiotics

The role of probiotics in acute gastroenteritis remains controversial with evolving evidence: [19]

ESPGHAN/ESPID Position:

• Certain specific strains may reduce diarrhea duration by ~1 day
• Not a priority intervention; ORT remains the focus
• If used, select evidence-based strains:
  • Lactobacillus rhamnosus GG
  • Saccharomyces boulardii

Recent Evidence: Two large RCTs (PROPS, Einstein-Probiotic) published in NEJM found NO benefit of Lactobacillus rhamnosus GG in acute gastroenteritis in US children, challenging earlier positive studies. [19]

Current Recommendation: Not routinely recommended; low priority compared to ORT

Antibiotic Therapy

Most acute gastroenteritis is viral and does NOT require antibiotics

Indications for Antibiotics

Clinical Pearl: Antibiotic Pearls:

1. STEC (E. coli O157:H7): AVOID antibiotics - may increase HUS risk by promoting toxin release [8]

2. Salmonella: Antibiotics may PROLONG carrier state in uncomplicated cases

3. Empiric antibiotics: Generally not recommended; await culture if needed

4. Ciprofloxacin: Avoid in children less than 18 years unless no alternative (cartilage toxicity concern, though evidence suggests low risk for short courses)

Antidiarrheal Agents

NOT recommended in children [1]

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Disposition

Discharge Criteria

A child with gastroenteritis can be safely discharged when:

1. Hydration status acceptable: Mild or no dehydration after ORT
2. Tolerating oral fluids: Keeping down ORS or clear fluids
3. Adequate urine output: Wet diaper or void observed
4. No red flags: No features suggesting alternative diagnosis
5. Reliable caregivers: Understand warning signs and follow-up
6. Access to ORS: Have or can obtain appropriate fluids
7. Follow-up arranged: Return precautions clear

Admission Criteria

Follow-Up Recommendations

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Special Populations

Infants less than 6 Months

Higher Risk Due To:

• Limited glycogen stores (hypoglycemia risk)
• Higher body water turnover
• Immature immune system
• Inability to communicate thirst
• Higher risk for serious bacterial infection

Management Considerations:

• Continue breastfeeding frequently (every 2-3 hours)
• Lower threshold for IV fluids
• Consider admission for observation
• Check glucose in ill-appearing infants
• Evaluate for UTI if febrile without clear source

Immunocompromised Children

At-Risk Populations:

• Primary immunodeficiency
• HIV/AIDS
• Post-transplant (solid organ, bone marrow)
• Oncology patients on chemotherapy
• Chronic immunosuppressive therapy

Considerations:

• Broader differential (CMV, MAC, microsporidia)
• Higher risk for severe/prolonged illness
• Lower threshold for stool studies
• May require antibiotics for pathogens usually self-limited
• Consider infectious disease consultation

Children with Chronic Diseases

Post-Travel Gastroenteritis

Consider:

• Bacterial pathogens: ETEC, Shigella, Salmonella, Campylobacter
• Parasites: Giardia, Cryptosporidium, Entamoeba
• Geographic-specific pathogens

Workup:

• Stool culture
• Ova and parasites x3
• Consider Giardia antigen
• C. difficile if recent antibiotics for travel

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Complications

Dehydration-Related Complications

Pathogen-Specific Complications

Secondary Complications

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Prevention

Vaccination

Rotavirus Vaccine

Two licensed vaccines with excellent efficacy: [6]

Important Notes:

• First dose by 14 weeks 6 days (maximum)
• Complete series by 8 months
• Contraindicated in severe combined immunodeficiency (SCID)
• History of intussusception is a contraindication
• Small increased risk of intussusception (1-2 per 100,000 vaccinees)

Hygiene and Infection Control

Travel Precautions

• "Boil it, cook it, peel it, or forget it"
• Avoid tap water, ice, and raw produce in high-risk areas
• Consider pre-travel consultation for high-risk destinations
• Carry ORS packets for self-treatment

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Patient and Family Education

Condition Explanation

For Parents/Caregivers:

"Your child has gastroenteritis, commonly called a 'stomach bug' or 'stomach flu.' This is an infection of the intestines, usually caused by a virus. It causes diarrhea, vomiting, and sometimes fever. Most children recover completely within a week without any specific treatment.

The most important thing is to prevent dehydration by giving your child plenty of fluids. We recommend using oral rehydration solution (like Pedialyte) in small, frequent amounts. It's okay to continue breastfeeding or formula feeding."

Home Care Instructions

Fluid Administration:

• Give small amounts frequently (1-2 teaspoons every few minutes)
• Use oral rehydration solution (Pedialyte or similar)
• Continue breastfeeding on demand
• Resume regular formula (do not dilute)
• Avoid juice, soda, and sports drinks

Feeding:

• Resume regular diet when vomiting subsides
• Start with bland foods if preferred, but no restrictions needed
• Do not force eating if child is not hungry

Hygiene:

• Wash hands thoroughly after diaper changes
• Keep child home from daycare until symptom-free 24-48 hours
• Clean contaminated surfaces with diluted bleach

Return Precautions (Warning Signs)

Return to Emergency Department Immediately If:

• Unable to keep any fluids down for more than 4-6 hours
• Blood in vomit or stool
• Green (bilious) vomit
• Severe abdominal pain
• No wet diaper for 6+ hours (infant) or no urination for 8+ hours (older child)
• Increasingly drowsy, difficult to wake, or not responding normally
• Sunken eyes, no tears when crying
• Fever not improving after 3 days
• Symptoms worsening instead of improving

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Exam Preparation

Common Examination Questions

1. "What are the causes of acute gastroenteritis in children?"
2. "How do you assess dehydration in a child?"
3. "What is the management of moderate dehydration due to gastroenteritis?"
4. "When would you give IV fluids instead of oral rehydration?"
5. "What are the indications for antibiotics in gastroenteritis?"
6. "A child presents with bloody diarrhea - what is your differential and approach?"
7. "What are the complications of Shiga toxin-producing E. coli infection?"
8. "How has rotavirus vaccination changed the epidemiology of gastroenteritis?"

Viva Points

Viva Point: Opening Statement: "Acute gastroenteritis is an infection of the gastrointestinal tract characterized by diarrhea with or without vomiting and fever. The most common cause in children is viral, particularly rotavirus and norovirus. The cornerstone of management is assessment and treatment of dehydration through oral rehydration therapy, with intravenous fluids reserved for severe dehydration or oral rehydration failure."

Key Facts to Quote:

• Rotavirus was the leading cause of severe gastroenteritis before widespread vaccination
• Norovirus is now the leading cause of medically-attended gastroenteritis in vaccinated populations
• Oral rehydration therapy is first-line for mild-moderate dehydration (WHO/ESPGHAN guidelines)
• Low-osmolarity ORS (245 mOsm/L) is superior to standard ORS
• Ondansetron reduces vomiting and IV fluid requirements
• Antibiotics are NOT indicated for most gastroenteritis (viral etiology)
• STEC: Antibiotics are CONTRAINDICATED due to HUS risk

Classifications to Know:

• WHO dehydration classification: None, Some (3-8%), Severe (≥9%)
• Diarrhea mechanisms: Secretory, Osmotic, Inflammatory, Dysmotility

Common Mistakes to Avoid

❌ Mistakes That Fail Candidates:

• Ordering excessive investigations for uncomplicated gastroenteritis
• Recommending IV fluids for mild-moderate dehydration
• Prescribing antibiotics routinely
• Recommending antidiarrheal agents (loperamide) in children
• Missing bilious vomiting as a surgical emergency
• Not considering intussusception in an infant with bloody stools
• Recommending dilution of formula
• Prescribing antibiotics for suspected STEC
• Not knowing WHO/ESPGHAN dehydration criteria
• Forgetting to mention ondansetron as adjunctive therapy

Model Answer

Q: "A 14-month-old presents with 2 days of diarrhea and vomiting. How would you assess and manage this child?"

A: "I would approach this child systematically.

Assessment: First, I would perform a focused history including onset, frequency of stools and vomiting, stool character, oral intake, urine output, sick contacts, recent travel, and immunization status including rotavirus.

On examination, my priority is assessing dehydration using the WHO criteria: general appearance, eyes, tears, mucous membranes, skin turgor, and capillary refill. I would categorize as no dehydration, some dehydration (3-8%), or severe dehydration (≥9%).

I would also perform an abdominal examination to exclude surgical causes, specifically looking for bilious vomiting, focal tenderness, distension, or mass.

Management based on dehydration:

• No dehydration: Home with oral rehydration solution 50-100 mL after each loose stool, continue breastfeeding, resume regular diet, return precautions.

• Some dehydration: Oral rehydration therapy with ORS 50-100 mL/kg over 4 hours in the emergency department, with small frequent sips. If vomiting persists, I would give a single dose of ondansetron (0.15 mg/kg) to facilitate oral rehydration. Reassess after 4 hours.

• Severe dehydration: IV access and 20 mL/kg normal saline bolus over 20 minutes, reassess, repeat as needed up to 60 mL/kg, then replace remaining deficit over 4 hours with isotonic fluids.

Investigations: Not routinely required for uncomplicated viral gastroenteritis. I would consider electrolytes if IV fluids needed, and stool culture only if bloody diarrhea, high fever, or immunocompromised.

Antibiotics: Not indicated in most cases as etiology is usually viral. I would specifically avoid antibiotics if STEC is suspected due to increased HUS risk.

Discharge: When tolerating oral fluids with adequate urine output and no concerning features, with clear return precautions and follow-up arranged."

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Key Clinical Pearls Summary

Clinical Pearl: ### Diagnostic Pearls

1. Clinical diagnosis: Gastroenteritis rarely requires laboratory confirmation
2. Weight is the gold standard for dehydration assessment but often unavailable
3. No single sign reliably detects dehydration - use combination assessment
4. Bilious vomiting = surgical emergency until proven otherwise
5. Bloody stool + no fever = Think STEC, avoid antibiotics

Treatment Pearls

1. ORT is first-line for mild-moderate dehydration
2. Small frequent volumes (5 mL every 1-2 minutes) are key
3. Ondansetron enables ORT - use it for persistent vomiting
4. Early feeding shortens illness - no need for prolonged clear liquids
5. Isotonic fluids for IV rehydration (0.9% NS or LR)
6. Antibiotics rarely indicated - most gastroenteritis is viral
7. No antidiarrheals in children (loperamide dangerous)

Disposition Pearls

1. Most children go home with ORS and education
2. Low threshold to admit young infants and immunocompromised
3. Caregiver education is critical for home success
4. Clear return precautions prevent adverse outcomes

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References

1. Guarino A, Ashkenazi S, Gendrel D, et al. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr. 2014;59(1):132-152. doi:10.1097/MPG.0000000000000375

2. GBD 2016 Diarrhoeal Disease Collaborators. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of diarrhoea in 195 countries: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Infect Dis. 2018;18(11):1211-1228. doi:10.1016/S1473-3099(18)30362-1

3. Freedman SB, Gouin S, Bhatt M, et al. Prospective assessment of practice pattern variations in the treatment of pediatric gastroenteritis. Pediatrics. 2011;127(2):e287-e295. doi:10.1542/peds.2010-2214

4. Hall AJ, Rosenthal M, Gregoricus N, et al. Incidence of acute gastroenteritis and role of norovirus, Georgia, USA, 2004-2005. Emerg Infect Dis. 2011;17(8):1381-1388. doi:10.3201/eid1708.101533

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