What is the treatment for acute gastroenteritis?

Treatment of Acute Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for acute gastroenteritis with mild to moderate dehydration in both children and adults, and should be initiated immediately without waiting for diagnostic testing. 1, 2

Initial Assessment

Evaluate hydration status through specific clinical signs 1, 2:

• Skin turgor (decreased indicates dehydration)
• Mucous membrane moisture (dry membranes indicate dehydration)
• Mental status (altered status indicates severe dehydration)
• Capillary refill (prolonged >2 seconds indicates dehydration)
• Vital signs (tachycardia indicates dehydration)
• Urine output (decreased indicates dehydration)

Categorize dehydration severity 1, 2:

• Mild: 3-5% body weight loss
• Moderate: 6-9% body weight loss
• Severe: ≥10% body weight loss

Rehydration Strategy

For Mild to Moderate Dehydration

Use low-osmolarity oral rehydration solution as first-line therapy 1, 2:

• Children and infants: 50-100 mL/kg over 3-4 hours 2
• Adolescents and adults: 2-4 L of ORS over 3-4 hours 2
• Commercially available products (e.g., Pedialyte, CeraLyte) are preferred 2

Critical pitfall to avoid: Do not use apple juice, sports drinks (Gatorade), or soft drinks as primary rehydration solutions—these contain high simple sugars that worsen diarrhea through osmotic effects 1, 2

If the patient refuses oral intake: Consider nasogastric administration of ORS at 50-100 mL/kg over 3-4 hours 1, 2

For Severe Dehydration

Administer intravenous rehydration immediately 1, 2:

• Use isotonic fluids (lactated Ringer's or normal saline) 1, 2
• Give 20 mL/kg bolus over 30 minutes 2
• Continue IV therapy until pulse, perfusion, and mental status normalize 1, 2
• Transition to ORS once the patient improves to replace remaining deficit 1

Other indications for IV therapy include shock, altered mental status, failure of oral rehydration, or ileus 1

Ongoing Maintenance

Replace ongoing losses with ORS until diarrhea and vomiting resolve 1, 2:

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

Nutritional Management

Resume feeding early—do not withhold food 1, 2:

• Continue breastfeeding throughout the diarrheal episode 1, 2
• Resume age-appropriate diet during or immediately after rehydration 1, 2
• Avoid fasting or restrictive diets for 24 hours as this does not improve outcomes 2

Critical pitfall: Delaying refeeding worsens outcomes and prolongs recovery 1, 2

Pharmacological Management

Antiemetics

Ondansetron may be given to children >4 years and adolescents with significant vomiting to facilitate oral rehydration 1, 2:

• Dose: 0.15 mg/kg per dose 2
• Important caveat: Ondansetron is used to reduce vomiting and facilitate ORS intake, not to treat diarrhea itself 3
• Contraindications: Avoid in inflammatory diarrhea (bloody diarrhea with fever) due to risk of toxic megacolon 3
• Avoid in children with cardiac disease due to QT prolongation risk 3

Antimotility Agents

Loperamide should NOT be given to children <18 years with acute diarrhea 1, 2:

• For immunocompetent adults only: May use loperamide for acute watery diarrhea once adequately hydrated 1, 2
• Adult dose: 4 mg initially, then 2 mg after each loose stool 2, 4
• Absolute contraindications: Inflammatory diarrhea, bloody diarrhea, fever, or suspected toxic megacolon 1, 2, 4

Critical distinction: Loperamide is a true antimotility agent that slows intestinal transit, while ondansetron is an antiemetic that does not affect motility 3

Antimicrobials

Antimicrobial agents have limited usefulness since viral pathogens cause most cases 1:

• Consider antibiotics only for: bloody diarrhea, recent antibiotic use, specific pathogen exposure, recent foreign travel, or immunodeficiency 1

Other Agents

Avoid adsorbents, antisecretory drugs, and toxin binders—these do not reduce diarrhea volume or duration 1

Probiotics may reduce symptom severity and duration in both adults and children 1

Infection Control

Implement strict infection control measures 1, 2:

• Hand hygiene with soap and water after toilet use, diaper changes, before food preparation, and before eating 1, 2
• Use gloves and gowns when caring for patients with diarrhea 1, 2
• Clean and disinfect contaminated surfaces promptly 1
• Separate ill persons from well persons until at least 2 days after symptom resolution 1

Key Clinical Pitfalls to Avoid

• Do not delay rehydration while awaiting diagnostic testing 1
• Do not use inappropriate fluids (juice, sports drinks) for moderate to severe dehydration 1
• Do not give antimotility drugs to children or in cases of bloody diarrhea 1
• Do not restrict diet unnecessarily during or after rehydration 1
• Do not neglect infection control measures as this leads to outbreaks 1