What are the standard treatment guidelines for acute gastroenteritis?

Standard Treatment Guidelines for Acute Gastroenteritis

Oral rehydration therapy (ORT) with low-osmolarity oral rehydration solution (ORS) is the cornerstone of treatment for mild to moderate dehydration, while intravenous fluids are reserved for severe dehydration or ORT failure. 1

Initial Assessment

Evaluate hydration status through specific physical examination findings rather than waiting for laboratory results 1:

• Decreased skin turgor, dry mucous membranes, sunken eyes 2, 1
• Altered mental status, tachycardia, decreased urine output 2, 1
• Capillary refill time and vital signs 3

Categorize dehydration severity 1, 3:

• Mild: <4% body weight loss (3-5%)
• Moderate: 4-6% body weight loss (6-9%)
• Severe: >6% body weight loss (≥10%)

Rehydration Strategy

Mild to Moderate Dehydration

Use commercially available low-osmolarity ORS (Pedialyte, CeraLyte) as first-line therapy—avoid apple juice, Gatorade, and soft drinks as primary rehydration solutions. 1

Dosing for rehydration phase 1:

• Infants and children: 50-100 mL/kg over 3-4 hours
• Adolescents and adults: 2-4 L over 3-4 hours

If the child refuses oral intake, nasogastric administration of ORS at 50-100 mL/kg over 3-4 hours is an effective alternative to IV therapy. 1, 3

Severe Dehydration

Administer isotonic IV fluids (lactated Ringer's or normal saline) at 20 mL/kg over 30 minutes for severe dehydration, shock, altered mental status, or ORT failure. 1, 3

Continue IV rehydration for 2-4 hours until pulse, perfusion, and mental status normalize, then transition to ORS for remaining deficit replacement 1, 3

Maintenance and Ongoing Loss Replacement

Replace ongoing losses with ORS until diarrhea and vomiting resolve 1, 3:

• Children <10 kg: 60-120 mL ORS per diarrheal stool/vomiting episode (up to ~500 mL/day) 1
• Children >10 kg: 120-240 mL ORS per diarrheal stool/vomiting episode (up to ~1 L/day) 1
• Adolescents and adults: ad libitum intake up to ~2 L/day 1

Nutritional Management

Continue breastfeeding throughout the diarrheal episode without interruption. 1, 3

Resume age-appropriate diet during or immediately after rehydration—fasting or withholding food for 24 hours does not improve outcomes and should be avoided. 1, 3

Pharmacological Adjuncts

Antiemetics

Ondansetron 0.15 mg/kg per dose may be given to children >4 years and adolescents with significant vomiting to facilitate oral rehydration. 1, 3

Antimotility Agents

Loperamide may be given to immunocompetent adults with acute watery diarrhea: 4 mg initially, then 2 mg after each loose stool. 1, 3

Absolutely avoid loperamide in children <18 years, and avoid all antimotility agents in cases of inflammatory diarrhea, bloody diarrhea, fever, or suspected toxic megacolon. 1, 3

Antimicrobials

Antimicrobial therapy is generally not indicated since viral pathogens predominate—reserve antibiotics only for specific bacterial pathogens with severe symptoms, bloody diarrhea, recent travel, or immunocompromised status. 2, 3

Critical Pitfalls to Avoid

Do not delay rehydration while awaiting diagnostic testing—initiate ORT immediately based on clinical assessment. 3

Do not use sports drinks, apple juice, or soft drinks as primary rehydration solutions for moderate to severe dehydration—these have inappropriate osmolarity and electrolyte composition. 1, 3

Do not administer antimotility drugs to children or in cases of bloody diarrhea, as this increases risk of complications including toxic megacolon and hemolytic uremic syndrome. 1, 3

Do not unnecessarily restrict diet during or after rehydration—early refeeding improves outcomes. 1, 3

Infection Control

Practice hand hygiene with soap and water (alcohol-based sanitizers are less effective against norovirus) after toilet use, diaper changes, before food preparation, and after handling animals. 1, 3

Use gloves and gowns when caring for patients with diarrhea, and separate ill persons from well persons until at least 2 days after symptom resolution. 3

Laboratory Investigation

Laboratory testing is generally not warranted for previously healthy immunocompetent patients with self-limited acute diarrhea. 2

Consider testing when 2:

• Bloody diarrhea or inflammatory features
• Severe dehydration or toxic appearance
• Immunocompromised status
• Recent antibiotic exposure (test for C. difficile)
• Outbreak situation or recent travel