MRCEM Notes

Gastroenteritis

Gastroenteritis may either occur whilst at home or whilst travelling abroad (travellers' diarrhoea)

Travellers' diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one or more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli.

Another pattern of illness is 'acute food poisoning'. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.

Stereotypical histories


InfectionTypical presentation
Escherichia coliCommon amongst travellers
Watery stools
Abdominal cramps and nausea
GiardiasisProlonged, non-bloody diarrhoea
CholeraProfuse, watery diarrhoea
Severe dehydration resulting in weight loss
Not common amongst travellers
ShigellaBloody diarrhoea
Vomiting and abdominal pain
Staphylococcus aureusSevere vomiting
Short incubation period
CampylobacterA flu-like prodrome is usually followed by crampy abdominal pains, fever and diarrhoea which may be bloody

Complications include Guillain-Barre syndrome
Bacillus cereusTwo types of illness are seen
  • vomiting within 6 hours, stereotypically due to rice
  • diarrhoeal illness occurring after 6 hours
AmoebiasisGradual onset bloody diarrhoea, abdominal pain and tenderness which may last for several weeks

Incubation period
  • 1-6 hrs: Staphylococcus aureus, Bacillus cereus*
  • 12-48 hrs: Salmonella, Escherichia coli
  • 48-72 hrs: Shigella, Campylobacter
  • > 7 days: Giardiasis, Amoebiasis

*vomiting subtype, the diarrhoeal illness has an incubation period of 6-14 hours
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