Gastroenteritis

Basics

Description

Inflammation of stomach and intestines associated with diarrhea and/or vomiting, often the result of infectious or toxin exposure

Etiology

Infectious

  • Viruses:
    • 50–70% of all cases
    • Rotavirus: More commonly affecting infants, overall incidence decreasing secondary to vaccines
    • Norovirus: Highly contagious, affecting all ages
  • Invasive bacteria:
    • Campylobacter: Contaminated food or water, wilderness water, birds, and animals:
      • Most common cause
      • Gross or occult blood is found in 60–90%
    • Salmonella: Contaminated water, eggs, poultry, or dairy products:
      • Typhoid fever (Salmonella typhi): Characterized by unremitting fever, abdominal pain, rose spots, splenomegaly, and bradycardia
      • Immunocompromised susceptible
    • Shigella: Fecal–oral route
    • Vibrio parahaemolyticus: Raw and undercooked seafood
    • Yersinia: Contaminated food (pork), water, and milk:
      • May present as mesenteric adenitis or mimic appendicitis
    • Specific food-borne disease (food poisoning):
    • Staphylococcus aureus:
      • Most common toxin-related disease
      • Symptoms within 1–6 hr after ingesting food
    • Bacillus cereus:
      • Classic source is fried rice left on steam tables
      • Symptoms within 1–36 hr
    • Cholera:
      • Profuse watery stools with mucous (rice-water stools)
    • Ciguatera:
      • Fish intoxication
      • Onset 5 min–30 hr (average 6 hr) after ingestion
      • Paresthesia, hypotension, peripheral muscle weakness
    • Scombroid:
      • Caused by blood fish: Tuna, albacore, mackerel, and mahi-mahi
      • Flushing, headache, erythema, dizziness, blurred vision, and generalized burning sensation
      • Symptoms last <6 hr
      • Treatment includes antihistamines
  • Protozoa:
    • Giardia lamblia:
      • High-risk groups: Travelers, daycare children, men who have sex with men, and campers who drink untreated mountain water

Noninfectious Causes

  • Toxins:
    • Zinc, copper, cadmium
    • Organic chemicals: Polyvinyl chlorides
    • Pesticides: Organophosphates
    • Radioactive substances
    • Alkyl mercury
  • Altered host response to food substance (tyramine, monosodium glutamate, tryptamine)

Pediatric Considerations

  • Focus evaluation on state of hydration
  • Most of viral origin and self-limited
  • Rotavirus accounts for up to 50%
  • Shigella infections associated with seizures

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