Acute Gastroenteritis (Diarrhea) in Children: Evaluation & Management Learning Tool

Clinical History Assessment

Systematic approach to history taking for a child presenting with acute gastroenteritis

Physical Examination Guide

Systematic approach to examining a child with acute gastroenteritis

Diagnostic Approach

Initial Assessment

For a child presenting with acute gastroenteritis, the initial assessment should include:

• Detailed history focusing on onset, frequency, and characteristics of diarrhea
• Assessment of dehydration status
• Evaluation of associated symptoms (vomiting, fever, abdominal pain)
• Exposure history (travel, sick contacts, food)

Diagnostic Criteria for Acute Gastroenteritis

Clinical definition of acute gastroenteritis in children:

Criteria	Definition	Key Features
WHO Definition	Passage of 3 or more loose or watery stools per day	Focus on increased frequency and decreased consistency
ESPGHAN Criteria	Decrease in stool consistency and/or increase in frequency (≥3 stools/24h), with or without fever or vomiting	Includes duration <14 days for acute cases
CDC Criteria	Diarrheal illness of rapid onset that may be accompanied by nausea, vomiting, fever, or abdominal pain	Emphasizes the acute nature and associated symptoms

Dehydration Assessment

Parameter	Mild Dehydration (3-5%)	Moderate Dehydration (6-9%)	Severe Dehydration (≥10%)
Mental Status	Alert, normal	Irritable, restless	Lethargic, obtunded
Thirst	Slightly increased	Moderately increased	Very thirsty or too lethargic to indicate
Heart Rate	Normal	Increased	Rapid, weak, or not palpable
Breathing	Normal	Normal to fast	Deep, rapid
Eyes	Normal	Sunken	Very sunken
Tears	Present	Decreased	Absent
Mouth/Tongue	Slightly dry	Dry	Very dry
Skin Pinch	Normal	Returns slowly	Returns very slowly (>2 seconds)
Capillary Refill	Normal	Prolonged (2-3 seconds)	Prolonged (>3 seconds)
Extremities	Warm	Cool	Cold, mottled, cyanotic
Urine Output	Slightly decreased	Decreased	Minimal or absent

Differential Diagnosis

Category	Conditions	Red Flags
Infectious Diarrhea	- Viral (Rotavirus, Norovirus, Adenovirus) - Bacterial (Salmonella, Shigella, E. coli) - Parasitic (Giardia, Cryptosporidium)	- Blood in stool - High fever - Severe abdominal pain - Recent travel - Exposure to untreated water
Systemic Infections	- Urinary tract infection - Otitis media - Pneumonia - Meningitis	- Fever without clear GI source - Dysuria, ear tugging - Respiratory symptoms - Nuchal rigidity, altered mental status
Surgical Conditions	- Appendicitis - Intussusception - Malrotation with volvulus - Incarcerated hernia	- Localized abdominal tenderness - Bilious vomiting - Currant jelly stools - Abdominal distension
Non-infectious GI disorders	- Inflammatory bowel disease - Celiac disease - Food allergies/intolerances - Irritable bowel syndrome	- Chronic/recurrent symptoms - Growth failure - Peri-umbilical rash - Family history
Medication/Toxin Related	- Antibiotic-associated diarrhea - C. difficile infection - Laxative abuse - Heavy metal poisoning	- Recent antibiotic use - Recurrent episodes - Unusual stool characteristics - Environmental exposures

Laboratory Studies

Consider these studies based on clinical presentation:

Investigation	Clinical Utility	When to Consider
Stool Studies (O&P, culture)	Identify causative pathogen	Bloody diarrhea, severe illness, immunocompromised, recent travel, outbreaks
Stool PCR Panel	Rapid detection of multiple pathogens	Severe or prolonged symptoms, hospitalized patients, immunocompromised
Complete Blood Count	Assess for inflammation, infection	Moderate-severe illness, high fever, bloody diarrhea
Electrolytes, BUN, Creatinine	Assess hydration status and electrolyte abnormalities	Moderate-severe dehydration, altered mental status, prolonged vomiting
Blood Culture	Identify bacteremia	Toxic appearance, immunocompromised, severe illness
Urinalysis and Culture	Rule out UTI	Fever without clear source, especially in young children

Advanced Studies

Reserve for atypical or severe presentations:

Investigation	Clinical Utility	When to Consider
Abdominal Imaging (X-ray, Ultrasound)	Evaluate for obstruction, ileus, or intussusception	Bilious vomiting, severe abdominal pain, distension, bloody stools
CT Abdomen	Evaluate for appendicitis or other surgical emergencies	Focal right lower quadrant pain, concerning ultrasound findings
Endoscopy	Direct visualization and biopsy	Chronic/recurrent symptoms, suspected IBD, celiac disease
Hydrogen Breath Test	Diagnose carbohydrate malabsorption	Suspected lactose intolerance, prolonged symptoms after acute infection
Toxicology Screen	Identify ingestions or poisonings	Suspicious history, unusual presentation, concern for non-accidental injury

Diagnostic Algorithm

A stepwise approach to diagnosing acute gastroenteritis:

1. Assess dehydration status using clinical parameters
2. Identify red flag symptoms requiring immediate intervention
3. Consider epidemiological factors (exposures, outbreaks, travel)
4. Determine need for laboratory testing based on severity and risk factors
5. Evaluate for mimicking conditions if presentation is atypical
6. Reassess diagnosis if symptoms persist beyond expected timeframe
7. Consider consultation for severe, unusual, or prolonged cases

Management Strategies

General Approach to Management

Key principles in managing acute gastroenteritis in children:

• Rehydration: Correct existing fluid deficits and replace ongoing losses
• Nutritional support: Early reintroduction of appropriate diet
• Symptomatic relief: Manage symptoms while avoiding harmful interventions
• Infection control: Prevent transmission to others
• Education: Parental guidance on warning signs and home care

Rehydration Strategies

Approach	Method	Evidence and Recommendations
Oral Rehydration Therapy (ORT)	- Use of oral rehydration solution (ORS) - Frequent small amounts - Replace ongoing losses	- First-line for mild to moderate dehydration - High-quality evidence supporting efficacy - Success rate >90% with proper administration - Cost-effective and accessible
Nasogastric Rehydration	- Continuous or bolus administration of ORS - Via nasogastric tube	- Equivalent efficacy to IV fluids - Consider when oral intake inadequate but GI tract functional - Less invasive than IV therapy - Suitable for moderate dehydration
Intravenous Rehydration	- Rapid (bolus) or slow continuous infusion - Isotonic fluids preferred	- Indicated for severe dehydration - When ORT fails or is contraindicated - Initial bolus (20mL/kg) of NS or LR - Reassess after each bolus
Maintenance Fluids	- Holliday-Segar method - ORS or IV depending on clinical status	- After correction of dehydration - Add replacement for ongoing losses - Monitor electrolytes if IV fluids > 24 hours - Transition to oral when possible

Oral Rehydration Solutions

Type	Composition	Indications/Comments
Standard WHO ORS	- Na⁺: 75 mEq/L - K⁺: 20 mEq/L - Cl⁻: 65 mEq/L - Citrate: 10 mEq/L - Glucose: 75 g/L (13.5 g/L)	- Universal standard - Effective for all causes of diarrhea - May not be palatable to some children
Reduced Osmolarity ORS	- Na⁺: 45-60 mEq/L - K⁺: 20 mEq/L - Reduced glucose - Total osmolarity: 210-268 mOsm/L	- Current WHO recommendation - Better tolerated - Reduces need for IV therapy - Suitable for all types of diarrhea
Commercial Pediatric ORS (Region-specific brands)	- Variable composition - Often flavored - May contain zinc, prebiotics	- Improved palatability - Similar efficacy to standard ORS - Choose products meeting WHO standards
Alternative Fluids (If ORS unavailable)	- Rice water with salt - Homemade sugar-salt solution	- Emergency use only - Potential for electrolyte imbalance - Replace with standard ORS when available

Nutritional Management

Recommendation	Approach	Evidence Level
Early Refeeding	- Continue breastfeeding throughout illness - Resume regular diet within 4-6 hours of ORT - No prolonged fasting	- High-quality evidence - Reduces illness duration - Improves nutritional outcomes - No increase in vomiting or diarrhea
Diet Selection	- Age-appropriate regular diet - Complex carbohydrates (rice, potatoes, bread) - Lean meats, yogurt - Fruits and vegetables	- Moderate evidence - Avoids nutritional deficits - Maintains gut integrity - Supports immune function
Foods to Avoid	- High simple sugar content (juices, sodas) - High fat foods - Spicy foods (temporarily)	- Limited evidence - Based on physiological principles - Individual tolerance varies
BRAT Diet	- Bananas, Rice, Applesauce, Toast - Historical approach	- Not recommended as exclusive diet - Insufficient calories and nutrients - May be included as part of normal diet

Pharmacological Management

Medication	Use and Dosing	Evidence and Recommendations
Zinc Supplementation	- Children <6 months: 10 mg daily - Children ≥6 months: 20 mg daily - For 10-14 days	- Strong evidence in developing countries - Reduces duration and severity - WHO recommended for all children with diarrhea in developing regions - Limited evidence in developed countries
Probiotics	- Lactobacillus GG: 10¹⁰ CFU/day - Saccharomyces boulardii: 250-750 mg/day - Other strains with varying evidence	- Moderate evidence for selected strains - Reduces duration by ~1 day - Strain-specific effects - Safe adjunctive therapy
Ondansetron	- Single dose based on weight: - 8-15 kg: 2 mg - 15-30 kg: 4 mg - >30 kg: 8 mg - Oral or ODT preferred	- Strong evidence for reducing vomiting - Improves ORT success - May increase diarrhea - Not for routine use but helpful in selected cases
Racecadotril	- 1.5 mg/kg/dose TID - Maximum 7 days	- Moderate evidence - Reduces stool output - Available in Europe, not in US - No significant adverse effects
Antimicrobials	- Pathogen-specific therapy - Based on local resistance patterns	- Not routinely recommended - Consider for: • Dysentery • Cholera • Suspected typhoid • Giardiasis • Amebiasis • C. difficile
Loperamide	- Not recommended in children <12 years	- Contraindicated in young children - Risk of ileus, toxic megacolon - Not recommended in acute infectious diarrhea

Management by Severity

Severity	Management Approach	Disposition
Mild (No/Minimal Dehydration)	- ORS to replace losses (5-10 mL/kg after each stool) - Continue normal diet - Consider zinc supplementation - Education on warning signs	- Home management - Follow-up as needed - Return if worsening symptoms
Moderate Dehydration	- ORS: 50-100 mL/kg over 3-4 hours - Reassess hydration status - Early refeeding - Replace ongoing losses	- Short observation may be needed - Home management if improved and tolerating ORT - Close follow-up
Severe Dehydration	- IV fluid resuscitation: 20 mL/kg boluses - Reassess after each bolus - Correct deficit within 4-6 hours - Monitor electrolytes - Transition to oral when stable	- Hospital admission - Consider ICU for shock - Discharge when rehydrated and tolerating oral intake
Complications Present	- Targeted management of complications: • Electrolyte abnormalities • HUS, acute kidney injury • Sepsis • Surgical abdomen	- Hospital admission - Specialist consultation as needed - Intensive monitoring

Special Considerations

• Young infants (<3 months): Lower threshold for evaluation and intervention
• Immunocompromised children: Higher risk for severe and prolonged illness
• Malnourished children: Special rehydration protocols may be needed
• Chronic medical conditions: Individualized fluid and electrolyte management
• Bloody diarrhea: Consider appropriate antimicrobial therapy after culture

Prevention

• Hand hygiene: Thorough handwashing with soap and water
• Food safety: Proper preparation, cooking, and storage
• Safe water: Treatment of suspicious water sources
• Vaccine prevention: Rotavirus vaccination per schedule
• Infection control: Isolation precautions for infectious cases

When to Refer

• Emergency evaluation: Severe dehydration, shock, altered mental status, intractable vomiting
• Hospital admission: Failed oral rehydration, severe dehydration, toxic appearance, underlying medical conditions
• Specialist referral: Prolonged symptoms (>2 weeks), growth failure, suspected inflammatory condition
• Return visit indicators: Persistent vomiting, worsening dehydration, bloody stools, high fever

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Patient Presentation

A 2-year-old male presents to the Emergency Department with a 2-day history of watery diarrhea (8-10 episodes/day), vomiting (6 episodes in the last 24 hours), and decreased oral intake. Parents report he had a low-grade fever (38.2°C) yesterday.

Key Presenting Symptoms:

• Watery diarrhea - no blood or mucus
• Non-bilious vomiting
• Decreased appetite and fluid intake
• Low-grade fever

Click to read about: ACUTE GASTROENTERITIS

Past Medical History

Previously healthy with normal growth and development. Vaccinations up to date, including rotavirus vaccine. No chronic medical conditions. No recent antibiotic use or travel history.

Physical Examination

Vital Signs:

• Temperature: 38.0°C
• Heart Rate: 130 beats/min
• Respiratory Rate: 28 breaths/min
• Blood Pressure: 90/60 mmHg
• Weight: 12 kg (documented weight loss of 0.8 kg from last well-child visit 2 weeks ago)

Physical Findings:

• General: Alert but irritable, appears moderately dehydrated
• HEENT: Dry mucous membranes, sunken eyes, delayed capillary refill (2-3 seconds)
• Cardiovascular: Tachycardic, normal heart sounds
• Respiratory: Clear breath sounds bilaterally
• Abdomen: Soft, non-tender, normal bowel sounds
• Skin: Decreased skin turgor, delayed skin pinch return
• Neurological: Age-appropriate, no focal deficits

Laboratory Findings

Basic Metabolic Panel:

• Na+: 138 mEq/L (135-145)
• K+: 3.3 mEq/L (3.5-5.0)
• Cl-: 102 mEq/L (98-108)
• HCO3-: 18 mEq/L (22-26)
• BUN: 18 mg/dL (7-20)
• Creatinine: 0.4 mg/dL (0.3-0.7)
• Glucose: 85 mg/dL (70-100)

Other Studies:

• Stool Studies: Negative for blood, leukocytes, and culture pending
• Urinalysis: Specific gravity 1.025, otherwise normal

Assessment

Primary Diagnosis:

Acute viral gastroenteritis with moderate dehydration (6-9% fluid deficit)

Evidence Supporting Diagnosis:

• Clinical presentation consistent with viral gastroenteritis
• Physical exam findings indicating moderate dehydration
• Laboratory findings showing mild metabolic acidosis and hypokalemia
• Age and vaccination status suggesting rotavirus less likely

Dehydration Assessment:

Moderate dehydration (6-9%) based on:

• Documented weight loss of ~6%
• Delayed capillary refill
• Decreased skin turgor
• Tachycardia
• Dry mucous membranes

Management Plan

Immediate Management:

1. IV Fluid Rehydration:
   • Calculate deficit: 7% of 12 kg = 840 mL
   • Initial bolus: 20 mL/kg NS (240 mL) over 1 hour
   • Remaining deficit plus maintenance over 24 hours
2. Electrolyte Replacement:
   • Add KCl 20 mEq/L to maintenance fluids after initial bolus
3. Monitoring:
   • Vital signs q2h
   • Input/output tracking
   • Serial weight measurements
   • Repeat electrolytes in 4-6 hours

Discharge Criteria:

• Adequate oral intake
• Normal vital signs
• Normalized electrolytes
• Parent education completed

Learning Points

Key Clinical Pearls:

1. Accurate assessment of dehydration severity is crucial for appropriate management
2. Weight loss is the most objective measure of dehydration
3. Most cases are viral and self-limiting; antibiotics are rarely indicated
4. Early rehydration and electrolyte correction improve outcomes
5. Regular reassessment is essential to guide therapy

Differential Diagnosis to Consider:

• Bacterial gastroenteritis
• Malabsorption syndromes
• Food intolerance
• Systemic infection
• Surgical abdomen

Clinical Presentations of Diarrhea in Children

1. Acute Watery Diarrhea

   Characterized by sudden onset of frequent, watery stools without blood or mucus. Often associated with vomiting and fever. Common causes include viral gastroenteritis (e.g., rotavirus, norovirus) and enterotoxigenic E. coli.

2. Dysentery (Bloody Diarrhea)

   Presents with frequent, small-volume stools containing visible blood and mucus. Often accompanied by abdominal pain, tenesmus, and fever. Common causes include Shigella, Campylobacter, and invasive E. coli.

3. Persistent Diarrhea

   Diarrhea lasting 14 days or more. May be associated with malnutrition, weight loss, and micronutrient deficiencies. Causes include persistent infections, post-infectious irritable bowel syndrome, or underlying gastrointestinal disorders.

4. Chronic Diarrhea

   Diarrhea lasting more than 30 days. May present with failure to thrive, anemia, and other signs of malnutrition. Causes include celiac disease, inflammatory bowel disease, cystic fibrosis, or congenital disorders.

5. Secretory Diarrhea

   Characterized by large-volume, watery stools that persist even with fasting. Often associated with electrolyte imbalances. Causes include cholera, carcinoid syndrome, or congenital chloride diarrhea.

6. Osmotic Diarrhea

   Occurs due to the presence of non-absorbable solutes in the intestine. Typically improves with fasting. Causes include lactose intolerance, sorbitol ingestion, or malabsorption syndromes.

7. Toddler's Diarrhea

   Chronic, non-specific diarrhea in otherwise healthy young children. Characterized by loose, frequent stools, often containing undigested food particles. Usually resolves spontaneously by school age.

Knowledge Check: Question and Answers for Medical Students & Professionals

This interactive quiz component covers essential viva questions and answers. It includes 30 high-yield viva questions with detailed answers.

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