NORWALK ENTERITIS

 

NORWALK ENTERITIS

 

DEFINITION:

A viral infectious disease of the small bowel caused by an RNA virus resulting in a cytotoxic diarrhea.

EPIDEMIOLOGY:

  • incidence: 5-15%
  • risk factors:
    • age: all ages except young infants, most > 5 years
    • season: all year, cold season peak
    • route: direct: fecal-oral
    • indirect: food, water, oysters, clams; airbourne
    • environ: epidemics - schools, camps, cruises, nursing homes
  • intubation period: 1-2 days

PATHOGENESIS:

1. Background

  • first identified in 1972 in Norwalk, Ohio
  • Norwalk virus is transmitted by a fecal-oral route and symptoms usually appear within 2 days of exposure. The viruses invade the mucosa of the proximal small bowel. No gastric or colonic involvement has been demonstrated. There is no change in cAMP levels (i.e., no increase in adenylate cyclase levels).

CLINICAL FEATURES:

1. Prodrome

  • mild fever, headache, abdominal pain and myalgias may be present and last for 12-24 hours

2. Diarrhea

  • large watery stools with no cells
  • diarrhea lasting only 1-2 days (not prolonged)
  • associated with nausea, vomiting, and abdominal cramps

3. Complications

  • chronic diarrhea (secondary to disaccharidase deficiency)
  • dehydration - severe dehydration is unusual
  • malabsorption - fat and D-xylose

INVESTIGATIONS:

1. Stool

  • Norwalk viruses detected with immune EM, RIA, and ELISA

2. Biopsy

  • Histologically there are patches of broad, blunt villi and some infiltration with mononuclear cells. EM shows shortening of the microvilli. These mucosal changes disappear within 2 weeks.

3. Serum

  • isonatremic dehydration

MANAGEMENT:

1. Supportive

  • oral rehydration fluid (ORF) or intravenous rehydration

 

 

 

Pediatric Database - NORWALK ENTERITIS

Pediatric Organization - Pedbase [at] Gmail.com