AUTHOR AND EDITOR INFORMATION

Section 1 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

INTRODUCTION

Section 2 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

Background

Acute gastroenteritis is a common cause of morbidity and mortality worldwide. Conservative estimates put diarrhea in the top 5 causes of deaths worldwide, with most occurring in young children in nonindustrialized countries. In industrialized countries, diarrheal diseases are a significant cause for morbidity across all age groups. Etiology includes bacteria, viruses, parasites, toxins, and drugs. Viruses are responsible for a significant percentage of cases affecting patients of all ages. Viral gastroenteritis ranges from a self-limited watery diarrheal illness (usually <1 wk) associated with symptoms of nausea, vomiting, anorexia, malaise, or fever to severe dehydration resulting in hospitalization or even death.

The clinician encounters acute viral gastroenteritis in 3 settings. The first is sporadic gastroenteritis in infants, which most frequently is caused by rotavirus. The second is epidemic gastroenteritis, which occurs either in semiclosed communities (eg, families, institutions, ships, vacation spots) or as a result of classic food-borne or water-borne pathogens. Most of these infections are caused by caliciviruses. The third is sporadic acute gastroenteritis of adults, which most likely is caused by caliciviruses, rotaviruses, astroviruses, or adenoviruses.

Pathophysiology

Viral spread from person to person occurs by fecal oral transmission of contaminated food and water. Some viruses, like noroviruses, may include possible airborne transmission. The exact mechanism of the induction of diarrhea is not clear. The most extensive studies have been done with rotavirus. Rotaviruses attach and enter mature enterocytes at the tips of small intestinal villi. They cause structural changes to the small bowel mucosa, including villus shortening and mononuclear inflammatory infiltrate in the lamina propria.

Morphologic abnormalities can be minimal, and recent studies demonstrate that rotavirus can be released from infected epithelial cells without destroying them. Viral attachment and entry into the epithelial cell without cell death may be enough to initiate diarrhea. The epithelial cell synthesizes and secretes numerous cytokines and chemokines, which can direct the host immune response and potentially regulate cell morphology and function. Recent studies also suggest that one of the nonstructural viral proteins may act as an enterotoxin, promoting active chloride secretion mediated through increases in intracellular calcium concentration. Toxin-mediated diarrhea would explain the observation that villus injury is not necessarily linked to diarrhea.

Frequency

United States

Each year, more than 3.5 million infants develop acute viral gastroenteritis, resulting in more than 500,000 office visits, 55,000 hospitalizations, and 30 deaths. Statistics on sporadic cases of adult viral gastroenteritis are not known; food- and water-borne epidemics of viral gastroenteritis are monitored by the US Centers for Disease Control and Prevention (CDC) surveillance programs. The CDC estimates that viruses cause 9.2 million (out of a total of 13.8 million from all causes) cases of food-related illness each year.

Noroviruses cause approximately 23 million cases of acute gastroenteritis each year and are the leading cause of outbreaks of gastroenteritis. They are responsible for 68-80% of all outbreaks in industrialized countries. The genus Norovirus was formerly called the Norwalk-like virus. The genus is in the family Caliciviridae. Noroviruses were attributed to 9 out of the 21 outbreaks of acute gastroenteritis on cruise ships reported to the CDC's Vessel Sanitation Program from January 1, 2002, to December 2, 2002.

Frequency is seasonal. The highest incidence of rotavirus cases occurs during the months from November to April. Cruise ship outbreaks of noroviruses are more common during summer months.

International

Acute viral gastroenteritis is a leading cause of infant mortality throughout the world. By age 3 years, virtually all children become infected with the most common agents.

Rotavirus causes 2 million hospitalizations and 600,000-875,000 deaths per year.

Mortality/Morbidity

Severe cases are seen in the elderly, infant, and immunosuppressed population, including transplant patients.

• Rotavirus infantile gastroenteritis is an important cause of infant mortality in the developing world.
• In the United States, elderly persons have the highest risk for death from gastroenteritis.
• Caliciviruses may kill more people in the United States than do rotavirus disease.

Age

• Acute viral gastroenteritis occurs throughout life. Severe cases are seen in very young and elderly. Etiology also varies with age.
• In infants, most cases are due to rotavirus.
• In adults, the most common cause is norovirus.

CLINICAL

Section 3 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

History

The clinical spectrum of acute viral gastroenteritis ranges from asymptomatic infection to severe dehydration and death. Viral gastroenteritis typically presents with short prodrome with mild fever and vomiting, followed by 1-4 days of nonbloody, watery diarrhea. Viral gastroenteritis is usually self-limited.

• The history should focus on severity and dehydration. The onset, frequency, quantity, and duration of diarrhea and vomiting are important factors in assessing the status. Oral intake, urination, and weight loss are important considerations. Viruses are the suspected cause of acute gastroenteritis when vomiting is prominent, when the incubation period is longer than 14 hours, and when the entire illness is over in less than 3 days. Travel history (including cruise ships), eating history, and daycare history are important epidemiology factors.
• A viral cause should be suspected when the warning signs of bacterial infection (ie, high fever, bloody diarrhea, severe abdominal pain, > 6 stools/24 h) are absent and an alternative diagnosis is not suggested by epidemiologic clues from the history (eg, travel, sexual practices, antibiotic use).
• Factors associated with severe and prolonged disease are immunodeficiency and immune suppression, comorbid disease, and malnutrition.
• Death results from dehydration and acidosis.
• Ruling out other diagnoses is important.

Physical

The physical examination can be helpful in determining the etiology of gastroenteritis and in assessing the presence and degree of dehydration.

• Temperature, blood pressure and pulse, and body weight can provide evidence of severity of the condition.
• Temperature may be slightly elevated. High fever suggests bacterial infection. Tachycardia, thready pulse, and hypotension suggest severe dehydration.
• The degree of weight loss may be related to dehydration and the duration of the diarrhea.
• The mucous membranes and the skin should be examined carefully. Dry mouth, no tears, skin tenting, dry skin, and capillary refill are all signs of dehydration.
• The mental status in elderly patients and infants may be abnormal, especially when blood pressure and circulation are compromised.
• The abdominal examination may demonstrate mild tenderness. Severe abdominal pain and tenderness suggest bacterial infection or an abdominal emergency.

Causes

• Sporadic infantile viral gastroenteritis
• • Group A rotavirus causes 25-65% of severe infantile gastroenteritis worldwide.
  • Acute infections with group C are quite frequent in the United States and worldwide.
  • After rotavirus, the most important cause of acute infantile gastroenteritis probably is calicivirus infection. Seroepidemiologic studies have shown that antibodies to caliciviruses are present in 50-90% of children younger than 2 years in Kuwait, Italy, Kenya, China, London, and South Africa. Using broadly reactive reverse-transcription polymerase chain reaction for calicivirus to study stool specimens from children with acute gastroenteritis, recent studies have found these viruses in 7-22% of cases.
  • Astrovirus infection is associated with 2-9% of cases of infantile gastroenteritis worldwide, making it the third most frequent cause after rotavirus and calicivirus. The burden of astrovirus disease in developing countries might be especially high.
  • Researchers have recognized for a long time that certain enteric adenoviruses are an important cause of infantile gastroenteritis. Recent studies confirm that they cause 2-6% of cases.
• Epidemic viral gastroenteritis
• • Most cases of epidemic viral gastroenteritis in adults and children are caused by the caliciviruses or small, round-structured viruses. Some examples include Norovirus (formerly called Norwalk-like viruses), genogroup I (eg, Norwalk, Southampton, Desert Shield, Cruise Ship); Norovirus (formerly Norwalk-like viruses), genogroup II (eg, Snow Mountain, Mexico, White River, Lordsdale, Bristol, Camberwell, Toronto, Hawaii, Melksham); and Sapovirus (formerly Sapporo-like viruses), which sometimes are referred to as genogroup III, although they are not like Norwalk (eg, Sapporo, Parkville, Manchester, Houston, London).
  • Modern molecular diagnostic techniques, such as broadly reactive reverse-transcription polymerase chain reaction, have linked these viruses to epidemics associated with oysters, contaminated community water supplies, restaurant food, hospital patients and staff, day-care facilities, nursing homes, college dormitories, military ships, cruise ships, and vacation spots.
  • Rotavirus and astrovirus also may cause epidemics of viral gastroenteritis.
• Sporadic adult viral gastroenteritis
• • Few studies have examined the causes of sporadic cases of adult viral gastroenteritis.
  • Seroepidemiologic evidence suggests that the etiologies are (in descending order of frequency) caliciviruses, non–group A rotavirus, astrovirus, and adenovirus.

DIFFERENTIALS

Section 4 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

WORKUP

Section 5 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

Lab Studies

• General laboratory evaluation
• • In most cases that fit the clinical features of viral gastroenteritis, lab tests are not indicated.
  • If bacterial or protozoal infection is suspected, stool studies for occult blood, WBC count, microscopy for protozoa, Clostridium difficile toxin, Giardia lamblia by enzyme immunoassay (EIA), or bacterial culture may be indicated.
  • Consider investigating high fever, abdominal pain, and extreme dehydration by evaluating serum electrolytes, urea, creatinine, amylase, CBC count, and abdominal imaging studies.
• Diagnosis of rotavirus infection
• • Rapid antigen testing of the stool, either by EIA (>98% sensitivity and specificity) or latex agglutination tests (less sensitive and specific as compared to EIA) is used to aid in the diagnosis of rotavirus infection.
  • Expect antirotavirus antibodies (immunoglobulin M and immunoglobulin A) to be excreted in the stool after the first day of illness. Antibody tests can remain positive for 10 days after primary infection and longer after reinfection; therefore, they can be used as an adjunct to diagnosis.
• Diagnosis of calicivirus infection
• • In epidemics, save stool and emesis specimens for evaluation by public health officials. PCR is valuable in both the outbreak setting and the sporadic case setting.
  • Researchers have cloned several of the caliciviruses and placed the genome in a baculovirus that produces unlimited amounts of recombinant calicivirus capsid protein. Enzyme immunoassays for serum antibody and stool antigen have been developed using this antigen source.
  • A modification to the polymerase chain reaction has allowed many of the different strains of caliciviruses to be recognized with just a few primers (broadly reactive reverse-transcription polymerase chain reaction). These primers are directed at a region of the genome that is common to many of the strains of calicivirus. This has been an important tool for identifying caliciviruses as the most common cause of epidemic viral gastroenteritis.

TREATMENT

Section 6 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

Medical Care

In 1996, the American Academy of Pediatrics formulated and published practice guidelines for the management of acute gastroenteritis in children. Use the following parameters to assess the degree of dehydration: blood pressure, pulse, heart rate, skin turgor, fontanelle, mucous membranes, eyes, extremities, mental status, urine output, and thirst.

• The treatment of rotavirus diarrhea is based primarily on replacing fluids and electrolytes, as directed by the estimated degree of dehydration.
• Oral rehydration therapy is recommended for preventing and treating early dehydration and continued replacement therapy for ongoing loses.
• Shock, severe dehydration, and decreased consciousness require intravenous therapy.
• Age-appropriate diets should be continued in children with diarrhea who are not dehydrated. When mild-to-moderately dehydrated children are rehydrated, resume age-appropriate diet.
• Administering antiemetics and antidiarrheal agents to small children is not recommended.
• Several studies have shown that antirotavirus immunoglobulin, as pooled gamma globulin, bovine colostrum, or human milk, may decrease frequency and duration of diarrhea.
• Research has consistently shown that probiotics, such as Lactobacillus casei GG and Saccharomyces boulardii, reduce the frequency and/or duration of diarrhea in acute infantile gastroenteritis by 30-70%. Their role in the treatment and prevention of acute infantile gastroenteritis is still undefined.
• Small studies have suggested that zinc supplements may reduce the severity and duration of illness.

FOLLOW-UP

Section 7 of 8  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

Deterrence/Prevention

• Natural infection with rotavirus does not afford complete immunity, and multiple infections in the first few years of life probably are common; however, immune response to these infections reduces the frequency and severity of subsequent rotavirus infection.
• On February 21, 2006, the CDC Advisory Committee on Immunization Practices (ACIP) recommended RotaTeq, an oral attenuated pentavalent live vaccine, for the vaccination of infants. Three doses should be given at 2, 4, and 6 months. The third dose should be given no later than 32 weeks.
• • In the REST trial, a double-blind placebo-controlled trial of over 60,000 infants, RotaTeq demonstrated a 74% reduction in all rotavirus cases. There was a 98% reduction in severe cases and a 96% reduction in hospitalized cases.
  • Of note, there was a 59% reduction in all-cause gastroenteritis admissions, highlighting rotavirus as a larger contributor to the cause of acute gastroenteritis than originally expected.
  • The oral live attenuated vaccine was not tested in immunocompromised patients and not approved for this use.
  • There was no association of RotaTeq with intussusception in this trial.
  • The former RotaShield virus was pulled from the market for increased intussusception. However, this risk was only seen in older infants. The RotaTeq trial did not test older infants. For these reasons, the RotaTeq virus is not approved for infants older than 32 weeks, and a "catch-up" vaccination is not recommended.
  • There are some questions as to the efficacy in less developed countries where the vaccine was not tested and nonvaccine serotypes (VP4, VP6, and VP7) are more prevalent.
  • Rotarix is a monovalent vaccine that has produced slightly less efficacious results than RotaTeq in clinical trials. This vaccine was tested in less developed countries. It is not yet approved for clinical use.
  • RotaShield is also not approved for use, but it is being considered for reintroduction into the marketplace in limited use for early infant vaccination only.
• Research on a vaccine for calicivirus infection is proceeding rapidly. Baculovirus-produced antigens spontaneously form viruslike particles without RNA that are immunogenic and possibly protective. Genomes also can be inserted into edible foodstuffs such as potatoes or bananas.
• Proper hygiene is still the first preventative step in viral gastroenteritis. Hand washing to prevent fecal oral transmission is very important. It also includes properly handling food and using clean water supplies.
• On a community level, proper sanitation, clean water supplies, and surveillance programs for outbreaks are important steps in prevention.

Patient Education

• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education article Gastroenteritis.

REFERENCES

Section 8 of 8

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• References

• American Academy of Pediatrics. Practice parameter: the management of acute gastroenteritis in young children. American Academy of Pediatrics, Provisional Committee on Quality Improvement, Subcommittee on Acute Gastroenteritis. Pediatrics. Mar 1996;97(3):424-35. [Medline].
• Ball JM, Graham DY, Opekun AR. Recombinant Norwalk virus-like particles given orally to volunteers: phase I study. Gastroenterology. Jul 1999;117(1):40-8. [Medline].
• Belhorn T. Rotavirus diarrhea. Curr Probl Pediatr. Aug 1999;29(7):198-207. [Medline].
• Bon F, Fascia P, Dauvergne M. Prevalence of group A rotavirus, human calicivirus, astrovirus, and adenovirus type 40 and 41 infections among children with acute gastroenteritis in Dijon, France. J Clin Microbiol. Sep 1999;37(9):3055-8. [Medline].
• Burkhart DM. Management of acute gastroenteritis in children [published erratum appears in Am Fam Physician 2000 May 1;61(9):2614]. Am Fam Physician. Dec 1999;60(9):2555-63, 2565-6. [Medline].
• Caeiro JP, Mathewson JJ, Smith MA. Etiology of outpatient pediatric nondysenteric diarrhea: a multicenter study in the United States. Pediatr Infect Dis J. Feb 1999;18(2):94-7. [Medline].
• Centers for Disease Control and Prevention. Withdrawal of rotavirus vaccine recommendation. JAMA. Dec 8 1999;282(22):2113-4. [Medline].
• Centers for Disease Control and Prevention. Outbreak of Gastroenteritis Associated with Noroviruses on Cruise Ships --- United States, 2002. MMWR Morb Mortal Wkly Rep 2002 Dec 13; 51(49): 1112-1115. [Full Text].
• Centers for Disease Control and Prevention. Advisory Committee Recommends New Vaccine to Prevent Rotavirus. [Full Text].
• Clark B, McKendrick M. A Review of Viral Gastroenteritis. Current Opinions in Infectious Disease. 2004;17(5):461-9.
• DuPont HL. Guidelines on acute infectious diarrhea in adults. The Practice Parameters Committee of the American College of Gastroenterology. Am J Gastroenterol. Nov 1997;92(11):1962-75. [Medline].
• Estes MK, Morris AP. A viral enterotoxin. A new mechanism of virus-induced pathogenesis. Adv Exp Med Biol. 1999;473:73-82. [Medline].
• Fankhauser RL, Noel JS, Monroe SS. Molecular epidemiology of "Norwalk-like viruses" in outbreaks of gastroenteritis in the United States. J Infect Dis. Dec 1998;178(6):1571-8. [Medline].
• Ford T. Emerging issues in water and health research. Journal of Water Health. 2006;4 supplement 1:59-65.
• Gaggero A, O''Ryan M, Noel JS. Prevalence of astrovirus infection among Chilean children with acute gastroenteritis. J Clin Microbiol. Dec 1998;36(12):3691-3. [Medline].
• Glass RI, Parashar UD. The Promise of New Rotavirus Vaccines. The New England Journal of Medicine. 2006;354 no. 1:75-77.
• Green J, Gallimore CI, Norcott JP. Broadly reactive reverse transcriptase polymerase chain reaction for the diagnosis of SRSV-associated gastroenteritis. J Med Virol. Dec 1995;47(4):392-8. [Medline].
• ICTVdb. The Universal Virus Database of the International Committee on Taxonomy of Viruses Web site. Available at: http://ictvdb.bio2.columbia.edu/Ictv/index.htm. Accessed on December 27, 2002.
• Maldonado Y, Cantwell M, Old M. Population-based prevalence of symptomatic and asymptomatic astrovirus infection in rural Mayan infants. J Infect Dis. Aug 1998;178(2):334-9. [Medline].
• Mead PS, Slutsker L, Dietz V. Food-related illness and death in the United States. Emerg Infect Dis. Sep-Oct 1999;5(5):607-25. [Medline].
• Pang XL, Joensuu J, Vesikari T. Human calicivirus-associated sporadic gastroenteritis in Finnish children less than two years of age followed prospectively during a rotavirus vaccine trial. Pediatr Infect Dis J. May 1999;18(5):420-6. [Medline].
• Pang XL, Koskenniemi E, Joensuu J. Effect of rhesus rotavirus vaccine on enteric adenovirus--associated diarrhea in children. J Pediatr Gastroenterol Nutr. Sep 1999;29(3):366-9. [Medline].
• Pang XL, Vesikari T. Human astrovirus-associated gastroenteritis in children under 2 years of age followed prospectively during a rotavirus vaccine trial. Acta Paediatr. May 1999;88(5):532-6. [Medline].
• Ruiz-Palacios G, Perez-Schael I, Velazquez FR. Safety and Efficacy of an Attenuated Vaccine against Severe Rotavirus Gastroenteritis. The New England Journal of Medicine. 2006;354 No. 1:11-22.
• Shornikova AV, Isolauri E, Burkanova L. A trial in the Karelian Republic of oral rehydration and Lactobacillus GG for treatment of acute diarrhoea. Acta Paediatr. May 1997;86(5):460-5. [Medline].
• Vesikari T, Matson D, Dennehy P. Safety and efficacy of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine. The New England Journal of Medicine. 2006;354(1):1747-51. [Medline]. [Full Text].

Article Last Updated: Jul 20, 2006