What is the recommended treatment for viral gastroenteritis, including rehydration, antiemetics, antidiarrheals, and supportive care?

Treatment of Viral Gastroenteritis

Oral rehydration therapy with reduced osmolarity oral rehydration solution (ORS) is the first-line treatment for viral gastroenteritis in patients with mild to moderate dehydration, and antimicrobials are not indicated. 1

Rehydration Strategy

Mild to Moderate Dehydration (3-9% fluid deficit)

• Administer reduced osmolarity ORS immediately as first-line therapy for all age groups—infants, children, and adults. 1, 2
• Continue ORS until clinical dehydration is corrected, then provide maintenance fluids and replace ongoing stool losses until diarrhea and vomiting resolve. 1
• For patients who cannot tolerate oral intake, consider nasogastric administration of ORS in those with normal mental status who are too weak or refuse to drink adequately. 1

Severe Dehydration (≥10% fluid deficit)

• Administer isotonic intravenous fluids (lactated Ringer's or normal saline) when there is severe dehydration, shock, altered mental status, failure of ORS therapy, or ileus. 1
• Continue IV rehydration until pulse, perfusion, and mental status normalize, the patient awakens, has no aspiration risk, and has no evidence of ileus. 1
• Once stabilized, transition to ORS to replace the remaining fluid deficit. 1
• In patients with ketonemia, an initial course of IV hydration may be needed to enable tolerance of oral rehydration. 1

Nutritional Management

• Continue breastfeeding throughout the diarrheal episode without interruption. 1
• Resume an age-appropriate usual diet immediately during or after the rehydration process is completed. 1
• Early refeeding decreases intestinal permeability, reduces illness duration, and improves nutritional outcomes. 2

Antiemetic Therapy

• Ondansetron may be given to children >4 years of age and adolescents with acute gastroenteritis associated with vomiting to facilitate tolerance of oral rehydration. 1, 2
• This is the only antiemetic with sufficient evidence to support use, and it should be used only after adequate hydration is achieved. 1
• Ondansetron decreases vomiting and hospitalization rates but may increase diarrhea episodes. 3

Antimotility Agents: Critical Restrictions

• Loperamide and other antimotility drugs are absolutely contraindicated in all children <18 years of age with acute diarrhea. 1, 2
• Loperamide may be given only to immunocompetent adults with acute watery diarrhea. 1, 2
• Avoid loperamide at any age in suspected or proven inflammatory diarrhea or diarrhea with fever due to risk of toxic megacolon. 1
• Reports from Pakistan documented severe abdominal distention and at least six deaths associated with loperamide use in children. 1

Antimicrobial Therapy

• Empiric antimicrobial therapy is not recommended for viral gastroenteritis or acute watery diarrhea without recent international travel. 1
• Watery diarrhea and vomiting in a child <2 years of age most likely represent viral gastroenteritis and do not require antimicrobial therapy. 1
• Exceptions may be made only for immunocompromised patients or ill-appearing young infants. 1

Adjunctive Therapies

• Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent adults and children with infectious diarrhea. 1, 2
• Oral zinc supplementation reduces diarrhea duration in children 6 months to 5 years of age who reside in countries with high zinc deficiency prevalence or who have signs of malnutrition. 1, 2
• Bismuth subsalicylate may provide symptomatic relief in adults, with studies showing reduction in illness duration. 2

Common Pitfalls to Avoid

• Do not use traditional "clear liquids" approaches—they are inadequate for rehydration. 4
• Do not rely on adsorbents (kaolin-pectin), as they do not reduce diarrhea volume or duration and may increase electrolyte losses. 1
• Do not use nonspecific antidiarrheal agents, as they shift therapeutic focus away from appropriate fluid and electrolyte therapy and can cause serious side effects including ileus and drowsiness. 1
• Ancillary treatments with antimotility, antinausea, or antiemetic agents are not substitutes for fluid and electrolyte therapy. 1

Infection Control

• Perform hand hygiene with soap and water after using the toilet, changing diapers, before and after preparing food, before eating, and after handling garbage or soiled laundry. 1, 2
• Exclude symptomatic staff from contact with susceptible persons for at least 2 days after symptom resolution. 2
• Clean environmental surfaces with special attention to areas soiled by feces or vomitus. 2