Gastroenteritis%20-%20viral Diagnosis

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

• Assess the onset, duration, frequency, quantity and character of vomiting and diarrhea
• Recent oral intake, urine output
• Consumption of contaminated food or drink 
• History of recent infections, recent antibiotic use 
• Exposure to family members or individuals with diarrhea
• Coexisting illness (eg immunodeficiencies, bone marrow transplant)
• Status of immunization
• Daycare attendance
• Community gastroenteritis outbreak 
• Recent travel to a diarrhea-endemic area 

• Vital signs
  • Temperature, heart rate, respiratory rate, blood pressure 
  • Actual body weight change by measuring the actual and 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 with isonatremic dehydration; doughy skin is a distinctive feature of hypernatremic dehydration
• Observe for changes in mental status
• Check for abdominal distension and tenderness, listen for bowel sounds

• Not routinely done
• Certain laboratory exams may be done when the underlying diagnosis is unclear
  
  • Stool culture should be considered in those with high fever and bloody diarrhea 
  • Complete blood count and blood culture should be considered if suspecting sepsis 
  • 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 (especially for detection of enteric adenovirus, enterovirus, parechovirus, and cytomegalovirus), polymerase chain reaction (PCR), reverse transcription-PCR, nucleic acid amplification test
• Freshly obtained stool sample is preferred for identification of offending pathogen 
• Serum electrolytes (eg bicarbonate, sodium), creatinine and glucose 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 and/or physical findings are inconsistent with their diarrheal episodes

Goals 

• To provide basis of treatment
• To identify patients who can safely be sent home for therapy, who should remain for observation during therapy and 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 (<5% in infants)
• Normal heart rate (HR), respiratory rate (RR) and pulse volume
• Normal eyes with presence of tears, moist mucous membranes
• Normal capillary refill
• Normal to decreased urine output
• Patient is well and alert

Mild to Moderate Dehydration 

• Consists of 6% loss of body weight (5-10% in infants)
• Normal to increased HR, RR
• Normal to decreased pulse volume
• Slightly sunken eyes with decreased tears, sticky mucous membranes
• Delayed capillary refill 
• Decreased urine output
• Patient may appear normal, listless or fatigued

Severe Dehydration 

• Consists of >9% loss of body weight (>10% in infants)
• Tachycardia with 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