Norovirus Gastroenteritis

Norovirus typically causes acute onset of vomiting, abdominal cramps, and diarrhea, with symptoms usually lasting 1 to 3 days. In children, vomiting is more prominent than diarrhea, whereas in adults, diarrhea usually predominates. Fluid losses vary from mild to severe dehydration Dehydration in Children Dehydration is significant depletion of body water and, to varying degrees, electrolytes. Symptoms and signs include thirst, lethargy, dry mucosa, decreased urine output, and, as the degree... read more .

Patients may also have fever, headache, and myalgias.

Diagnosis of norovirus is usually based on clinical suspicion in a patient with typical symptoms, especially during an outbreak.

Laboratory testing can confirm the diagnosis of norovirus infection using RT-PCR on a stool sample. This test is usually done as a multiplex PCR panel including a number of causes of gastroenteritis. Caution must be used when interpreting a positive test result for norovirus because there can be asymptomatic shedding, which the very sensitive PCR test can detect. A positive test result for norovirus in a patient with atypical symptoms, such as bloody diarrhea, or in a patient testing positive for another pathogen suggests that norovirus is not the cause of the gastroenteritis.

Supportive care, including rehydration with fluids and electrolytes, is the mainstay of treatment and is all that is needed for most adults. Oral glucose-electrolyte solutions, broth, or bouillon may prevent dehydration or treat mild dehydration. Children may become dehydrated more quickly and should be given an appropriate oral rehydration solution (several are available commercially—see Oral Rehydration Oral Rehydration Oral fluid therapy is effective, safe, convenient, and inexpensive compared with IV therapy. Oral fluid therapy is recommended by the American Academy of Pediatrics and the World Health Organization... read more ). An antiemetic (eg, ondansetron) may be given if vomiting makes oral rehydration difficult.

Isotonic IV fluids such as Ringer’s lactate and normal saline solution should be given when there is severe dehydration, hypovolemic shock, or altered mental status and failure of oral rehydration therapy or ileus (see also the Infectious Diseases Society of America's [IDSA] 2017 clinical practice guidelines for the diagnosis and management of infectious diarrhea). In severe dehydration, IV rehydration should be continued until pulse, perfusion, and mental status normalize.

Antidiarrheal agents should not be given to children < 18 years of age with acute diarrhea (see the IDSA guidelines). Antidiarrheals can be considered in adult patients with watery diarrhea (as shown by heme-negative stool), especially during an outbreak, suggesting a viral cause is likely. However, antidiarrheals may cause deterioration of patients with Clostridioides difficile or E. coli O157:H7 infection and thus should not be given to any patients in whom the cause of diarrhea has not been identified and in whom these disorders may be suspected (ie, based on recent antibiotic use, bloody diarrhea, heme-positive stool, or diarrhea with fever).

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.