What is the recommended treatment for a patient with viral gastroenteritis?

Treatment of Viral Gastroenteritis

Oral rehydration therapy (ORT) is the cornerstone and first-line treatment for viral gastroenteritis, as it is as effective as intravenous therapy for mild-to-moderate dehydration and directly addresses the primary risk of death from this self-limited illness. 1, 2

Rehydration: The Primary Treatment Goal

Oral Rehydration Therapy

• ORT should be initiated immediately based on clinical assessment without waiting for laboratory results, as viral gastroenteritis is self-limited but dehydration poses the main mortality risk 1, 2
• Use oral rehydration solutions (ORS) for mild to moderate dehydration in all age groups—infants, children, and adults 1
• ORT is equally effective as IV therapy for mild-to-moderate dehydration and should be the default approach 1, 3
• Continue ORS until clinical dehydration is corrected, then provide maintenance fluids and replace ongoing stool losses until diarrhea and vomiting resolve 1

When to Use Nasogastric or Intravenous Routes

• Consider nasogastric ORS administration in patients with moderate dehydration who cannot tolerate oral intake, or in children with normal mental status who are too weak or refuse to drink 1
• Reserve intravenous fluids (lactated Ringer's or normal saline) for severe dehydration, shock, altered mental status, failure of ORT, or ileus 1
• In severe dehydration, continue IV rehydration until pulse, perfusion, and mental status normalize, then transition to ORS for remaining deficit replacement 1
• Patients with ketonemia may need initial IV hydration to enable tolerance of oral rehydration 1

Nutritional Management

Feeding During Illness

• Continue breastfeeding throughout the diarrheal episode without interruption, as breast milk has protective effects against enteric infections 1, 2
• Resume age-appropriate usual diet during or immediately after rehydration is completed 1
• Early refeeding decreases intestinal permeability, reduces illness duration, and improves nutritional outcomes 2

Lactose Considerations

• Most infants can be "fed through" viral gastroenteritis episodes despite mild lactose intolerance that may persist 10-14 days post-rotavirus infection 2
• A lactose-free diet reduces diarrhea duration by an average of 18 hours in children under 5 years, though most completely recover without dietary modification 2

Symptomatic Treatment

Antiemetics

• Ondansetron may be given to children >4 years of age and adolescents with acute gastroenteritis associated with vomiting to facilitate oral rehydration tolerance 1
• Antiemetics are not routinely recommended but ondansetron specifically has evidence for enhancing ORT compliance and decreasing hospitalization rates 3

Antimotility Agents: Critical Age-Based Restrictions

• Loperamide is contraindicated in all children <18 years of age with acute diarrhea 1, 4
• Loperamide may be given to immunocompetent adults with acute watery diarrhea only 1
• Avoid loperamide at any age in inflammatory diarrhea, diarrhea with fever, or bloody diarrhea due to risk of toxic megacolon 1, 4
• Never exceed recommended loperamide dosages due to cardiac risks including QT prolongation, Torsades de Pointes, and sudden death 4
• Avoid loperamide in patients taking CYP3A4 inhibitors (itraconazole), CYP2C8 inhibitors (gemfibrozil), P-glycoprotein inhibitors (quinidine, ritonavir), or QT-prolonging drugs 4

Other Symptomatic Measures

• Bismuth subsalicylate may provide modest symptomatic relief, potentially reducing illness duration by approximately 7 hours 2
• Ancillary treatments can be considered once adequate hydration is achieved, but are not substitutes for fluid and electrolyte therapy 1

Special Population Considerations

Pediatric Patients

• Children are at highest risk for dehydration due to greater fluid loss relative to body size 2
• Use special caution with all medications in children due to greater variability of response 4
• Dehydration further influences variability of drug response, particularly in children <6 years 4

Elderly Patients

• Elderly patients, especially those on diuretic medications, require heightened attention to hydration status 2
• Avoid loperamide in elderly patients taking QT-prolonging drugs or with cardiac risk factors 4

Pregnant Women

• No evidence indicates viral gastroenteritis poses particular threat to pregnancy beyond dehydration risks 2
• Viremic states do not occur with gastroenteritis viruses, so transplacental exposure risk is minimal to nonexistent 2

Adjunctive Therapies

Probiotics

• Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent adults and children with infectious diarrhea 1
• Specific organism selection, route, and dosage should be guided by literature searches and manufacturer guidance 1

Zinc Supplementation

• 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

Infection Control Measures

Hand Hygiene and Isolation

• Vigorous handwashing with soap for at least 10 seconds is essential after toilet use, diaper changes, before food preparation and eating, and after touching animals or contaminated surfaces 1
• Exclude symptomatic staff from contact with susceptible persons for at least 2 days after symptom resolution 1, 2
• Separate ill persons from well persons until at least 2 days after symptom resolution 1, 2

Environmental Cleaning

• Clean soiled surfaces (especially feces or vomitus) of visible material first, then disinfect with commercial germicidal products 1
• Use appropriate protective barriers including gloves, gowns when fecal contamination possible, and masks when cleaning grossly contaminated areas 1
• Handle soiled linens with minimal agitation, transport in enclosed manner, machine wash with detergent at maximum cycle, and machine dry 1

Critical Pitfalls to Avoid

Diagnostic Red Flags

• Bloody diarrhea is NOT typical of viral gastroenteritis and requires investigation for bacterial or other causes 1, 2
• Do not assume viral etiology without considering alternative diagnoses when clinical features are atypical 1

Treatment Errors

• Do not delay ORT while awaiting laboratory confirmation—begin rehydration immediately 2
• Do not withhold feeding during illness; early refeeding improves outcomes 1, 2
• Do not use antimotility agents in children or in any patient with inflammatory features 1, 4
• Do not exceed recommended loperamide dosages or use in combination with interacting medications 4

When to Seek Higher Level Care

• Signs of severe dehydration: decreased urine output, dry mouth and tongue, sunken eyes, no tears when crying (children), unusual drowsiness or lethargy 2
• Persistent symptoms beyond 1 week warrant further investigation 1
• Development of constipation, abdominal distention, or ileus requires immediate discontinuation of loperamide 4