How should viral gastroenteritis (stomach flu) be managed?

Management of Viral Gastroenteritis (Stomach Flu)

The primary treatment for viral gastroenteritis is immediate oral rehydration therapy (ORT) to prevent dehydration, as the condition is self-limited and resolves within days without specific antiviral therapy. 1

Immediate Rehydration Strategy

Oral rehydration therapy should be initiated immediately based on clinical assessment without waiting for laboratory results. 1 This is the cornerstone of management and is equally effective as intravenous therapy for mild-to-moderate dehydration. 1

Rehydration Protocol:

• Use oral rehydration solutions (ORS) containing physiological concentrations of glucose and electrolytes for all age groups—infants, children, and adults. 1
• Continue ORS until clinical dehydration is corrected, then provide maintenance fluids and replace ongoing stool losses until diarrhea and vomiting resolve. 1
• Reserve hospitalization and intravenous fluids only for severe dehydration or when adequate oral rehydration cannot be provided. 1
• Serum electrolytes, creatinine, and glucose measurements are unnecessary in most cases. 2

Symptomatic Management

Antiemetic Therapy:

• Ondansetron may be given to children over 4 years of age and adolescents with significant vomiting to facilitate oral rehydration. 1
• A single oral dose of ondansetron reduces gastroenteritis-related vomiting and facilitates ORT without significant adverse events. 3

Antidiarrheal Medications:

• Loperamide is contraindicated in all children under 18 years of age with acute diarrhea. 1
• Loperamide may be considered for immunocompetent adults with acute watery diarrhea only—avoid in inflammatory diarrhea or fever. 1
• Bismuth subsalicylate may provide modest symptomatic relief, reducing illness duration by approximately 7 hours (from 27 to 20 hours in Norwalk infection). 4, 1

Nutritional Management

Continue feeding throughout illness, as early refeeding decreases intestinal permeability, reduces illness duration, and improves nutritional outcomes. 1

Feeding Guidelines:

• Breast milk has protective effects against enteric infections—most infants can be "fed through" an episode. 4, 1
• Infants may experience mild lactose intolerance for 10-14 days following rotavirus infection, but most completely recover. 4
• A lactose-free diet reduces diarrhea duration by an average of 18 hours in children under 5 years of age. 1

Adjunctive Therapies:

• Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent adults and children. 1
• 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

Special Population Considerations

Children:

• Children are at highest risk for dehydration but respond well to oral rehydration therapy. 4, 1
• Lack of access to medical care, rather than disease virulence, is a principal risk factor for death from gastroenteritis. 4

Elderly Patients:

• Maintenance of good hydration is particularly important among the elderly and those receiving diuretic medications. 4, 1
• Diuretic medications and debility can increase the risk of adverse outcomes in what otherwise might be a mild diarrheal episode. 4

Pregnant Women:

• Dehydration and electrolyte imbalance pose risks to pregnancy, but no evidence indicates that viral agents of gastroenteritis constitute a particular threat beyond this. 4, 1
• Viremic states from these agents are not known to occur in humans, so the risk of transplacental exposure, fetal demise, or malformation is likely low or nonexistent. 4

Infection Control Measures

Vigorous handwashing with soap for at least 10 seconds is essential after toilet use, diaper changes, before food preparation and eating, and after touching contaminated surfaces. 4, 1

Isolation and Exclusion:

• Ill persons should be separated from well persons until at least 2 days after resolution of symptoms. 4, 1
• Staff members with symptoms should be excluded from contact with susceptible persons for at least 2 days after resolution of illness—this is particularly important for food handlers. 4, 1
• For nosocomial rotavirus, isolation should continue until the ill person's stool is negative by antigen detection, which may be ≥1 week. 4

Environmental Cleaning:

• Surfaces soiled by feces or vomitus should first be cleaned of visible material and then disinfected with an appropriate commercial germicidal product. 4
• Personnel cleaning contaminated areas should wear disposable plastic gloves, and masks should be considered when cleaning areas grossly contaminated by feces or vomitus due to potential aerosol transmission. 4

Laundry Precautions:

• Soiled linens should be handled with minimum agitation, transported in plastic bags if wet or moist, machine washed with detergent at maximum cycle length, and then machine dried. 4

When to Seek Medical Care

Medical attention should be sought for signs of severe dehydration, including: 1

• Decreased urine output
• Dry mouth and tongue
• Sunken eyes
• No tears when crying (in children)
• Unusual drowsiness or lethargy

Critical Pitfalls to Avoid

• Do not delay ORT waiting for laboratory results—begin rehydration immediately based on clinical assessment. 1
• Do not assume viral etiology if bloody diarrhea is present—this is atypical and requires investigation for bacterial or other causes. 2
• Do not give antimotility drugs to children under 18 years of age. 1
• Do not use rectal swabs for viral diagnosis—they have little to no diagnostic value; bulk stool specimens collected within the first 48 hours of illness are required. 4, 2