Synopsis
Recognise viral gastroenteritis, correct dehydration safely, distinguish dangerous mimics and interrupt norovirus transmission across healthcare and community settings.
- Norovirus commonly causes abrupt vomiting, watery diarrhoea and rapid spread; fever is usually low grade and illness is often short.
- Assess hydration from physiology and urine output, not from stool frequency alone; older adults may present with falls, confusion or acute kidney injury.
- Oral rehydration is preferred when tolerated; shock requires prompt isotonic intravenous crystalloid with reassessment after every bolus.
Key red flags
Persistent hypotension, mottling, confusion or oliguria indicates severe hypovolaemia or sepsis.
Tachycardia, postural or persistent hypotension, dry mucosa, delayed capillary refill, reduced urine output and acute confusion indicate clinically important volume depletion.
Investigation priorities
Determine immediate resuscitation, admission and escalation needs before seeking an organism.
Management branches
Vomiting or diarrhoea has produced clinically important dehydration or circulatory compromise.
- Use ABCDE, measure glucose and urine output, establish access and identify cardiac or renal conditions that change fluid tolerance.
- Offer correctly prepared oral rehydration in frequent small volumes when the airway is safe and perfusion is adequate.
Key medicines
Oral rehydration solutionReconstitute a licensed sachet exactly as directed and give frequent small oral volumes, replacing ongoing losses according to clinical response.
Isotonic crystalloid for resuscitationGive 500 mL containing sodium 130 to 154 mmol/L intravenously over less than 15 minutes for adult hypovolaemic shock, then reassess.