What is the management and treatment of acute gastroenteritis?

Management and Treatment of Acute Gastroenteritis

Rehydration: The Cornerstone of Treatment

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

Assessment of Hydration Status

Evaluate dehydration severity through specific clinical signs 1, 2, 3:

• Skin turgor (decreased indicates dehydration)
• Mental status (altered with worsening dehydration)
• Mucous membrane moisture (dry membranes indicate dehydration)
• Capillary refill time (prolonged >2 seconds suggests dehydration)
• Vital signs (tachycardia, hypotension in severe cases)
• Urine output (decreased or absent)

Categorize dehydration severity 1, 2, 3:

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

Oral Rehydration Protocol

Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte)—not sports drinks, apple juice, or soft drinks, which can worsen diarrhea through osmotic effects. 1, 2

Dosing for mild to moderate dehydration 1, 2:

• Infants and children: 50-100 mL/kg over 3-4 hours
• Adolescents and adults: 2-4 L over 3-4 hours
• If vomiting is severe: Start with small volumes (5-10 mL) using a syringe or dropper, gradually increasing as tolerated 1

Replace ongoing losses 1, 2:

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

For children refusing oral intake: Consider nasogastric administration of ORS at 50-100 mL/kg over 3-4 hours 2

Intravenous Rehydration

Reserve IV fluids exclusively for 1, 2, 3:

• Severe dehydration (≥10% body weight loss)
• Shock or altered mental status
• Failure of oral rehydration therapy
• Ileus

IV protocol 2, 3:

• Isotonic fluids: Lactated Ringer's or normal saline
• Initial bolus: 20 mL/kg over 30 minutes
• Continue until pulse, perfusion, and mental status normalize (typically 2-4 hours)
• Transition to ORS once patient improves to replace remaining deficit 1

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration—do not fast or restrict diet. 1, 2, 3

• Continue breastfeeding throughout the illness in infants 1, 2, 3
• Early refeeding improves outcomes compared to prolonged fasting 1, 2
• Avoid foods high in simple sugars (soft drinks, undiluted apple juice) as they worsen diarrhea 1

Pharmacological Management

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, 2, 3

This reduces hospitalization rates and improves ORS tolerance 4

Antimotility Agents

Loperamide is absolutely contraindicated in children <18 years with acute diarrhea. 1, 2, 3

For immunocompetent adults with acute watery diarrhea 1, 2, 5:

• May use loperamide once adequately hydrated
• Initial dose: 4 mg, then 2 mg after each loose stool 2
• Contraindications: Bloody diarrhea, fever, inflammatory diarrhea, suspected toxic megacolon 2, 5
• Caution: Avoid in elderly patients on QT-prolonging drugs (Class IA/III antiarrhythmics) 5
• Drug interactions: CYP3A4 inhibitors (itraconazole), CYP2C8 inhibitors (gemfibrozil), and P-glycoprotein inhibitors (quinidine, ritonavir) increase loperamide exposure 2-12 fold, raising cardiac risk 5

Probiotics and Zinc

• Probiotics may reduce symptom severity and duration in both adults and children 1
• Zinc supplementation (for children 6 months to 5 years) reduces diarrhea duration in areas with high zinc deficiency or in malnourished children 1, 3

Antimicrobials

Antimicrobial therapy is NOT routinely indicated, as viral agents cause the majority of cases. 1, 6

Consider antimicrobials only for 1, 6:

• Bloody diarrhea with fever
• Recent antibiotic use (test for Clostridioides difficile)
• Recent foreign travel
• Immunodeficiency
• Symptoms persisting >1 week
• Confirmed bacterial or parasitic infection requiring treatment

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

Infection Control Measures

Practice rigorous hand hygiene 1, 2, 3:

• After using toilet or changing diapers
• Before and after food preparation
• Before eating
• After handling soiled items or animals

Use contact precautions 1, 3:

• Gloves and gowns when caring for patients with diarrhea
• Clean and disinfect contaminated surfaces promptly with appropriate disinfectants
• Isolate ill persons from well persons until at least 2 days after symptom resolution 1, 3

Monitoring and Reassessment

Reassess hydration status after 2-4 hours of ORS therapy 1:

• If still dehydrated, reestimate deficit and restart rehydration
• Monitor vital signs, capillary refill, skin turgor, mental status, and urine output every 2-4 hours 1
• Track daily weights to assess rehydration progress 1

Seek immediate medical attention if 5:

• No clinical improvement within 48 hours
• Blood in stools develops
• Fever or abdominal distention occurs
• Fainting, rapid/irregular heartbeat, or unresponsiveness develops

Critical Pitfalls to Avoid

• Never delay rehydration while awaiting diagnostic testing 1
• Never use inappropriate fluids (apple juice, sports drinks) as primary rehydration for moderate-severe dehydration 1
• Never give antimotility drugs to children or in cases of bloody diarrhea 1, 2
• Never unnecessarily restrict diet during or after rehydration 1, 2
• Never neglect infection control measures, as this leads to outbreaks 1