Rotavirus

Essentials of Diagnosis

• Nonbloody diarrhea of 2-8 days’ duration.
• Vomiting, fever, anorexia, and dehydration common.
• May infect any age group.
• Most common etiology of acute gastroenteritis in children < 2 years of age.
• Yearly reinfection common in infants and young children.

General Considerations

Epidemiology

Rotavirus is the most common etiology of acute diarrheal illness in children < 2 years old. It is responsible for > 1 million cases of reported diarrheal illness each year in children ages 1-4 years in the United States. Rotavirus is responsible for an average of 150 deaths per year in this same group. All of these deaths are secondary to severe dehydration. Worldwide, rotavirus is estimated to be responsible for 125 million cases of diarrhea in children < 5 years old. This effect results in mortality in 873,000 of these children. Mortality in developed counties has been reduced by aggressive rehydration therapy.

Microbiology

Rotavirus is a 70-nm icosahedral RNA reovirus that has five distinct antigenic groups (A, B, C, D, and E). Group A also has six serotypes. Group A is responsible for the majority of reported diarrheal illnesses in children in the United States. Groups B and C are responsible for adult diarrheal illnesses in Asia.

Pathogenesis

The virus is transmitted human to human via the fecal-oral route. The incubation time in humans is 1-3 days. Clinical disease is most prevalent in the winter. Rotavirus is also the most common cause of nosocomial diarrheal illness in children. Investigators have hypothesized a possible respiratory transmission route.

Clinical Findings (see Box 1)

Signs and Symptoms

Infants and children present with nonbloody diarrhea, which is often profuse. Emesis, anorexia, fever, and irritability are also common. In immunocompetent individuals, the disease is self-limited and lasts 2-8 days. The key to management is evaluation of the level of dehydration at presentation. Children in the category of severe dehydration are usually acidotic and require immediate intervention. Clinically, children with severe dehydration can appear lethargic, obtunded, or in shock. Rarely, respiratory symptoms are present including rhinorrhea, cough, and wheeze. Some children with moderate dehydration also warrant prompt intervention.

Laboratory Findings

Group A rotavirus antigen may be detected from stool through either enzyme immunoassay (EIA) or latex agglutination (LA). Both are equally sensitive and specific for detection of rotavirus during the acute diarrheal phase of the disease. EIA has higher sensitivity when used late in the course of disease.

Imaging

Imaging has little value in rotavirus-induced gastroenteritis. Rare cases of paralytic ileus secondary to hypokalemia have been observed by abdominal radiography.

Differential Diagnosis

The differential diagnosis of acute winter childhood diarrheal illness should always include rotavirus, Norwalk virus, calcivirus, astrovirus, and coronavirus (see site). In warm weather diarrhea, adenovirus is more common. If blood is present in the stool, bacterial agents should be considered, including, enteropathogenic E coli, Shigella, Salmonella, Yersinia, and Campylobacter species. If symptoms are prolonged or atypical, malabsorptive or maldigestive diarrhea, as well as intestinal parasites, should be considered.

Complications

Common complications are dehydration, uncommonly accompanied by electrolyte imbalances. Owing to mucosal damage of the small bowel lumen, transient lactose intolerance is uncommonly observed. Prolonged diarrhea or severe cramping, gas, or colic can be the result of lactase deficiency. If lactase deficiency is suspected, the patient should be placed on a lactose-free diet for 2-5 days.

Diagnosis

Diagnosis of rotavirus is based on history and physical findings. Since this virus produces a self-limiting disease in healthy individuals, identification of the virus is not needed in most cases. In immunocompromised patients, identification of an etiology is a higher priority, and stool should be sent promptly for analysis. Serum electrolytes and glucose should be evaluated in patients with moderate to severe dehydration.

Treatment

The primary therapy for rotavirus gastroenteritis is hydration (Box 2). If appropriate oral hydration can maintain fluid balance, no other intervention is needed. Small children and infants are prone to dehydration. Assessing the level of dehydration is key to deciding on therapy. Oral rehydration is appropriate for most children with mild to moderate dehydration. Parenteral rehydration is often needed if oral rehydration fails. Patients with severe dehydration warrant prompt parenteral rehydration. Careful attention should be paid to their hemodynamic status. Patients with either hypo- or hypernatremia should be slowly rehydrated to account for sodium or free-water deficits.

Orally administered immunoglobulin may modify the course of the illness in patients with immunodeficiencies who experience a prolonged rotaviral illness. Routine use is not recommended.

Prevention & Control

Rotavirus is spread by direct contact. Hand washing should limit spread of the virus (Box 3). Careful attention should be paid to potential fomites, especially in the hospital setting. Strict enteric isolation should be observed for all symptomatic hospitalized patients. Nosocomial infections with rotavirus are common. Infants and children should be excluded from school or daycare if their stool can not be contained. An oral, live-attenuated tetravalent vaccine was licensed by the FDA in 1998. In clinical trials, it significantly reduced morbidity. In 1999, the vaccine was taken off the market to investigate a possible relationship to intussusception. The results of this investigation are pending.

BOX 1. Rotavirus Gastroenteritis Clinical Syndrome

More Common

• Nonbloody diarrhea of 2- to 8-d duration
• Vomiting, anorexia, and fever
• Isotonic dehydration
• Pharyngeal eyrthema

Less Common

• Hyper- or hyponatremic dehydration
• Transient lactose intolerance
• Rhinitis
• Wheezing
• Cervical lymphadenopathy
• Serous otitis media

BOX 2. Treatment of Rotavirus Gastroenteritis

Primary Treatment

• Oral rehydration should be utilized for patients with mild (5%) to moderate (10%) isotonic dehydration
• Parenteral rehydration should be reserved for moderate to severe dehydration, to correct electrolyte abnormalities, and for patients failing oral rehydration
• Acetaminophen (10 to 15 mg/kg every 4 h orally or rectally) or ibuprofen (6 to 8 mg/kg every 6 to 8 h orally) for fever and irritability
• Age appropriate oral feeding should resume slowly when vomiting subsides and rehydration is complete
• Withholding lactose does not improve outcome in the majority of patients

Pediatric Considerations

• Correct sodium abnormalities slowly
• Consider transient lactase deficiency if diarrhea persists more than 5 days
• Antidiarrheal agents are contraindicated in children

BOX 3. Control of Rotavirus Gastroenteritis

Prophylactic Measures

• Hand washing
• Disinfection or disposal of all potential fomites
• Breast feeding decreases the severity of illness in young children
• An oral, live-attentuated tetravalent vaccine will be commercially licensed in the very near future for use in infants and young children.

Isolation Precautions

• Strict enteric isolation of all hospitalized patients
• If stool cannot be contained, infants and young children should be restricted from daycare, school settings, or both until diarrhea ceases