What is the recommended treatment for a patient with norovirus, particularly for managing symptoms and preventing dehydration?

Norovirus Treatment

The cornerstone of norovirus treatment is oral rehydration therapy with reduced osmolarity oral rehydration solution (ORS), which should be initiated immediately for mild to moderate dehydration, while severe dehydration requires intravenous isotonic fluids followed by transition to ORS once stabilized. 1, 2

Clinical Presentation and Natural Course

Norovirus causes acute gastroenteritis with sudden onset of nonbloody diarrhea, vomiting, nausea, and abdominal cramps after a 12-48 hour incubation period. 1 Some patients experience only vomiting or diarrhea. 1 Low-grade fever and body aches may occur. 1 Symptoms typically resolve without treatment after 1-3 days in otherwise healthy persons, though more prolonged courses lasting 4-6 days can occur in young children, elderly persons, and hospitalized patients. 1

Assessment of Dehydration Severity

Before initiating treatment, assess dehydration severity through physical examination: 2, 3

• Mild dehydration (3-5% fluid deficit): Increased thirst, slightly dry mucous membranes 2, 3
• Moderate dehydration (6-9% fluid deficit): Loss of skin turgor, dry mucous membranes 2, 3
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting, hypovolemic shock 2, 3

Rehydration Protocol

Mild to Moderate Dehydration

Administer reduced osmolarity ORS as first-line therapy using WHO-recommended formulations (e.g., Pedialyte, Ceralyte, or generic solutions). 1, 2, 3 The dosing is: 2, 3

• Mild dehydration: 50 mL/kg over 2-4 hours
• Moderate dehydration: 100 mL/kg over 2-4 hours
• After each bowel movement: Adults should consume as much ORS as desired 1, 2

If the patient cannot tolerate oral intake, consider nasogastric tube administration at 15 mL/kg/hour. 2, 3

Severe Dehydration

Severe dehydration constitutes a medical emergency requiring immediate intravenous isotonic fluids (Ringer's lactate or normal saline) in 20 mL/kg boluses. 2, 3 Continue IV rehydration until pulse, perfusion, and mental status normalize. 2, 3 Once stabilized, transition to ORS for replacing the remaining fluid deficit. 2, 3

Ongoing Management

After initial rehydration, provide maintenance fluids and replace ongoing losses with ORS until diarrhea and vomiting resolve. 2, 3 Reassess hydration status after 3-4 hours and continue treatment according to the degree of dehydration. 2, 3

Nutritional Support

Resume appropriate diet during or immediately after rehydration—there is no justification for "resting the intestine" through fasting, as this delays recovery. 2 Foods rich in energy and easily digestible help maintain nutritional status. 2

Hand Hygiene and Infection Control

Thorough handwashing with soap and running water for at least 20 seconds is the most effective way to reduce norovirus contamination on hands. 1 Alcohol-based hand sanitizers show limited efficacy against norovirus and should not substitute for soap and water handwashing, though they may serve as an adjunct between proper handwashings. 1

Exclude and isolate infected persons during the acute phase of illness and for 24-72 hours following recovery while still shedding virus at high levels. 1 This is particularly important in congregate settings like long-term care facilities, hospitals, and cruise ships. 1

Fluids to Avoid

Do not use popular beverages like apple juice, Gatorade, or commercial soft drinks for rehydration—they lack the appropriate electrolyte composition and can worsen dehydration due to high osmolality. 2, 3, 4 While one study suggested Gatorade may be effective for mild viral gastroenteritis, hypokalemia persisted in the Gatorade group, making it less ideal than proper ORS. 5

Medications: What NOT to Use

Antimotility agents (such as loperamide), antidiarrheal drugs, stimulants, steroids, and purgatives are contraindicated in norovirus gastroenteritis—they can produce adverse effects and should not be used as routine treatment for uncomplicated watery diarrhea. 2, 6 The FDA-approved loperamide is indicated for other forms of diarrhea but not recommended for viral gastroenteritis. 6

Bismuth subsalicylate showed modest benefit in one study (reducing Norwalk infection duration from 27 to 20 hours), but this is not a standard recommendation. 1

Special Populations

Elderly Patients

Approximately 10% of persons with norovirus seek medical attention, which may include hospitalization and treatment for dehydration. 1 Norovirus-associated deaths have been reported among elderly persons, particularly in long-term care facility outbreaks. 1 Maintain heightened vigilance for dehydration in this population. 1

Immunocompromised Patients

While norovirus is typically self-limited, immunocompromised patients may develop chronic diarrhea lasting months to years, resulting in severe malnutrition and continuous viral shedding. 7 Several treatment strategies have been suggested in case reports (nitazoxanide, ribavirin, enterally administered immunoglobulin) with varying results, though no specific antiviral therapy is established. 7, 8

Common Pitfalls to Avoid

• Do not delay treatment for severe dehydration—it constitutes a medical emergency 2
• Do not use alcohol-based hand sanitizers as a substitute for soap and water handwashing 1
• Do not withhold food—resume normal diet immediately after rehydration 2
• Do not use antimotility agents in uncomplicated viral gastroenteritis 2, 6