What is the recommended treatment for acute gastroenteritis in adults and children?

Treatment of Acute Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for mild to moderate dehydration in both children and adults with acute gastroenteritis, with intravenous fluids reserved only for severe dehydration, shock, altered mental status, or failure of oral rehydration. 1, 2

Rehydration Strategy by Severity

Mild Dehydration (3-5% fluid deficit)

• Administer ORS at 50 mL/kg over 2-4 hours 2
• Replace ongoing losses with 10 mL/kg ORS for each watery stool and 2 mL/kg for each vomiting episode 1, 2
• Continue ORS until clinical dehydration is corrected 1

Moderate Dehydration (6-9% fluid deficit)

• Administer 100 mL/kg ORS over 2-4 hours 1, 2
• Use small, frequent volumes (5-10 mL every 1-2 minutes) via spoon or syringe to prevent triggering vomiting 2
• This technique successfully rehydrates >90% of children with vomiting and diarrhea without antiemetic medication 2
• If oral intake fails, consider nasogastric administration of ORS in patients who cannot tolerate oral intake or refuse to drink 1, 2

Severe Dehydration (≥10% fluid deficit)

• Administer isotonic intravenous fluids (lactated Ringer's or normal saline) immediately 1, 2
• Continue IV rehydration until pulse, perfusion, and mental status normalize 1, 2
• Transition to ORS to replace remaining deficit once patient improves 1, 2
• Oral rehydration is as effective as IV rehydration for preventing hospitalization in mild-moderate cases, with treatment failure occurring in only 4% of ORT cases 3

Nutritional Management

• Resume age-appropriate diet during or immediately after rehydration is completed 1, 2
• Continue breastfeeding throughout the diarrheal episode 1, 2
• Early refeeding reduces severity and duration of illness 2
• Avoid foods high in simple sugars (soft drinks, undiluted apple juice), as they exacerbate diarrhea through osmotic effects 2
• Avoid caffeinated beverages, as caffeine stimulates intestinal motility and worsens diarrhea 2

Pharmacological Management

Antiemetics

• Ondansetron may be given to children >4 years and adolescents to facilitate oral rehydration when vomiting is significant 1, 2
• A single oral dose reduces vomiting and facilitates ORT without significant adverse events 4
• Use only after adequate hydration attempts, not as substitute for fluid therapy 1

Antimotility Agents

• Loperamide is absolutely contraindicated in all children <18 years with acute diarrhea 1, 2, 5
• Loperamide may be given to immunocompetent adults with acute watery diarrhea once adequately hydrated 1, 2
• Avoid loperamide in suspected inflammatory diarrhea, bloody diarrhea, or fever at any age due to risk of toxic megacolon 1
• Maximum adult dose is 16 mg (eight 2 mg capsules) per day 5

Probiotics and Zinc

• Probiotics may reduce symptom severity and duration in immunocompetent adults and children 1, 2
• Zinc supplementation (10-20 mg daily) reduces diarrhea duration in children 6 months to 5 years in areas with high zinc deficiency prevalence or malnutrition 1, 2

Infection Control Measures

• Practice hand hygiene 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 2
• Separate ill persons from well persons until at least 2 days after symptom resolution 2

Critical Pitfalls to Avoid

• Do not delay rehydration while awaiting diagnostic testing—initiate ORS immediately 2
• Do not use sports drinks or apple juice as primary rehydration solutions for moderate-severe dehydration; use proper low-osmolarity ORS 2
• Do not give antimotility drugs to children or in cases of bloody diarrhea 1, 2
• Do not restrict diet unnecessarily during or after rehydration 1, 2
• Do not use adsorbents, antisecretory drugs, or toxin binders—they lack demonstrated effectiveness 2
• Do not routinely prescribe antimicrobials, as viral agents predominate and antibiotics are only indicated for specific bacterial pathogens 2

Indications for Hospitalization

• Severe dehydration (≥10% fluid deficit) with signs of shock 1, 2
• Altered mental status or lethargy 1, 2
• Failure of oral rehydration therapy despite proper technique 1, 2
• Intractable vomiting despite ondansetron 2
• Ileus (absent bowel sounds) 1, 2
• Infants <3 months, elderly patients, or immunocompromised patients with lower threshold for admission 2