What is the appropriate management of norovirus gastroenteritis?

Management of Norovirus Gastroenteritis

Oral rehydration therapy with reduced osmolarity oral rehydration solution (ORS) is the cornerstone of norovirus management, with aggressive fluid replacement being the primary treatment goal since norovirus gastroenteritis is self-limited and requires no specific antiviral therapy. 1, 2

Clinical Recognition

Norovirus presents with acute onset of nonbloody diarrhea and vomiting after a 12-48 hour incubation period, often accompanied by nausea, abdominal cramping, low-grade fever, and body aches. 1, 3

• In immunocompetent individuals, symptoms typically resolve within 1-3 days without specific therapy. 1
• Prolonged illness lasting 4-6 days occurs more frequently in young children, older adults, and hospitalized patients. 1, 2
• Immunocompromised patients may develop chronic norovirus diarrhea lasting months to years, representing a severe disease course with mortality rates up to 25% in allogeneic stem cell transplant patients. 1, 3

Rehydration Protocol

Assessment of Dehydration Severity

Assess dehydration through physical examination: 1

• Mild dehydration: increased thirst, slightly dry mucous membranes
• Moderate dehydration: loss of skin turgor, dry mucous membranes
• Severe dehydration: severe lethargy or altered consciousness, prolonged skin tenting, hypovolemic shock

Treatment Based on Severity

For mild to moderate dehydration, administer reduced osmolarity ORS as first-line therapy: 1

• Mild dehydration: 50 mL/kg over 2-4 hours
• Moderate dehydration: 100 mL/kg over 2-4 hours

For severe dehydration, treat as a medical emergency with immediate intravenous isotonic fluids in 20 mL/kg boluses, then transition to ORS once stabilized. 1

Provide maintenance fluids and replace ongoing losses with ORS until diarrhea and vomiting resolve, and resume appropriate diet during or immediately after rehydration. 1

Adjunctive Therapy

For immunocompetent adults with nonbloody diarrhea, antimotility agents may be used as part of self-treatment. 2

Infection Control Measures

Hand Hygiene

Handwashing with soap and running water for at least 20 seconds is the most effective method to remove norovirus from hands. 1, 2 Alcohol-based hand sanitizers (≥70% ethanol) may be used as an adjunct but cannot replace soap-and-water washing for norovirus decontamination. 1

Isolation and Work Exclusion

Isolate affected residents or patients in institutional settings until 24-48 hours after symptoms have ceased. 1, 2

Exclude ill healthcare workers, food handlers, and childcare workers from work until 48-72 hours after symptom resolution. 1, 2 This is critical because viral shedding peaks 2-5 days after infection and can continue for an average of 4 weeks, and infected persons may be contagious during the 24-48 hours before symptoms appear. 3, 2

Environmental Decontamination

Apply a chlorine bleach solution at 1,000-5,000 ppm (approximately a 1:50-1:10 dilution of household bleach) or an EPA-approved disinfectant after first removing visible soil. 1 This is essential because norovirus is extremely contagious with an infectious dose as low as 18 viral particles. 4

Special Population Considerations

Elderly Patients

Elderly individuals, especially those in long-term-care facilities, have experienced norovirus-related deaths during outbreak investigations. 1, 2 Maintain heightened vigilance for dehydration in this population. 1

Immunocompromised Patients

Obtain stool specimens during the acute phase for RT-qPCR diagnosis in immunocompromised patients, as this is the most reliable diagnostic method. 2

Evaluate for other opportunistic pathogens, including Cryptosporidium, Cyclospora, microsporidia, Cystoisospora belli, CMV, and MAC, particularly in HIV-infected patients. 2

When to Escalate Care

Vomiting or diarrhea persisting for more than one week is atypical and requires immediate evaluation for alternative diagnoses. 2 Do not assume all cases resolve within 1-3 days, as elderly, young children, and hospitalized patients frequently have more prolonged courses. 2

Common Pitfalls

• Relying on alcohol-based hand sanitizers alone: These cannot replace soap-and-water handwashing for norovirus. 1
• Premature return to work: Viral shedding continues for weeks after symptom resolution, and up to 30% of infections are asymptomatic yet still contagious. 3
• Inadequate environmental cleaning: Standard cleaning agents may not be effective; chlorine bleach solutions at appropriate concentrations are required. 1
• Underestimating severity in vulnerable populations: Norovirus can cause significant morbidity and mortality in elderly and immunocompromised patients. 1, 3