gastroenteritis%20-%20viral
GASTROENTERITIS - VIRAL
Acute gastroenteritis is a diarrheal disease of rapid onset.
Viruses are one of the common causes of gastroenteritis.
Rotavirus, enteric adenovirus serotypes 40 & 41, astrovirus and calicivirus (eg "Norwalk-like" virus) are the established viral agents causing gastroenteritis.
Rotavirus is the most common pathogen causing diarrhea in patients 3-24 months old.
Patients <3 months old are protected by maternal rotavirus antibodies that are passed transplacentally and possibly by breastfeeding.
Transmission is through fecal-oral route.
Incubation period may vary from 1-10 days depending on the causative agent.

Diagnosis

  • Diagnosis can be made on the basis of detailed history & physical exam

Assessment

Goals
  • To provide basis of treatment
  • To identify patients who can safely be sent home for therapy, who should remain for observation during therapy & who may need hospitalization for intensive therapy
Dehydration Assessment
  • Isotonic dehydration is a common finding in patients with rotavirus gastroenteritis
Minimal or No Dehydration
  • Consists of <3% loss of body weight
  • Normal heart rate (HR), respiratory rate (RR) & pulse volume
  • Normal eyes w/ presence of tears, moist mucous membranes
  • Normal capillary refill
  • Normal to decreased urine output
  • Patient is well & alert
Mild to Moderate Dehydration
  • Consists of 3-9% loss of body weight
  • Normal to increased heart rate, respiratory rate
  • Normal to decreased pulse volume
  • Slightly sunken eyes with decreased tears, dry mucous membranes
  • Delayed capillary refill 
  • Decreased urine output
  • Patient may appear normal, listless or fatigued
Severe Dehydration
  • Consists of >9% loss of body weight
  • Tachycardia w/ bradycardia especially in severe cases, deep respirations
  • Thready to absent pulse
  • Deeply sunken eyes with absence of tears, parched mucous membranes
  • Poor capillary refill
  • Minimal urine output
  • Patient may appear lethargic to comatose

History

  • Assess the onset, frequency, quantity & character of vomiting & diarrhea
  • Urine output
  • Recent oral intake
  • Daycare attendance
  • History of recent infections, exposure to children with diarrhea
  • Coexisting illness (eg immunodeficiencies, bone marrow transplant)

Physical Examination

  • Vital signs
    • Temperature, heart rate (HR), respiratory rate (RR), blood pressure (BP)
    • Actual body weight change by measuring the actual & pre-illness body weight
    • Considered the gold standard measure of dehydration
  • Signs of dehydration (eg sunken eyes, dry mucous membranes, decreased tears, skin tenting, doughy feel to the skin)
    • Tenting of the skin is associated w/ isonatremic dehydration; doughy skin is a distinctive feature of hypernatremic dehydration
  • Observe for changes in mental status
  • Listen for bowel sounds

Laboratory Tests

  • Not routinely done
  • Certain laboratory exams may be done when the underlying diagnosis is unclear
    • May also be necessary for surveillance
  • Most widely used assays for viral pathogen detection are the following: Electron microscopy, enzyme immunoassay, latex agglutination, gel electrophoresis, viral culture, polymerase chain reaction (PCR), reverse transcription-PCR
  • Serum electrolytes may be useful in assessing moderate to severe dehydration especially in patients who require intravenous (IV) or nasogastric (NG) fluids
    • May also be done in patients whose histories &/or physical findings are inconsistent with their diarrheal episodes
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