Norovirus Clinical Presentation

Updated: Sep 27, 2018
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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Presentation

History

Symptomatic gastroenteritis typically develops 24-48 hours after ingestion of contaminated food or water or after contact with an infected individual. Each episode is short-lived, lasting only 24-72 hours. The onset can be abrupt or gradual.

Symptoms include the following:

  • Nausea and vomiting (profuse, nonbloody, nonbilious)

  • Watery diarrhea (nonbloody)

  • Abdominal cramps

  • Headaches

  • Low-grade fever is common (but temperatures may be higher as well)

  • Myalgias and malaise

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Physical

Vital signs include low-grade fever, tachycardia, and possible hypotension with volume depletion.

Abdominal examination reveals the absence of focal tenderness and peritoneal signs.

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Causes

Vectors for norovirus infection include the following:

  • Water sources include both potable water and lake or swimming pool water (when ingested); noroviruses are relatively resistant to inactivation by chlorine.

  • Food sources include shellfish (eg, oysters, clams), salads, cake frosting, and meats. Spread can occur through undercooked contaminated foods or improper hand washing by an infected food handler.

  • Body fluid sources include vomitus and feces from infected individuals. Maximal viral shedding occurs during the first 48 hours of illness; however, viruses can be detected in stool up to 3 weeks after illness resolves. [20]

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Complications

Significant electrolyte and blood chemistry abnormalities such as hypokalemia, hyponatremia, metabolic alkalosis, and elevated creatinine phosphokinase can occur in patients with pre-existing conditions such as inflammatory bowel disease, renal failure, immunocompromising conditions, and cardiovascular disease. Severe clinical features, including acute renal failure, arrhythmia, and signs of acute organ rejection in renal transplant patients were observed in a university hospital outbreak. [21]

One case of norovirus encephalopathy was reported in a 23-month-old child. [22]

Hemolytic uremic syndrome has been reported in association with norovirus gastroenteritis in a patient with chronic renal failure. [23]

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