Infectious Gastroenteritis
Acute inflammation of the gut caused by ingested pathogens or their toxins, producing diarrhoea and vomiting whose pattern and severity reflect the underlying mechanism of mucosal injury.
First principles
Diarrhoea is either secretory/toxin-mediated or invasive/inflammatory, and the mechanism predicts the picture
Pathogens cause diarrhoea by one of two broad mechanisms. Toxin-mediated illness (preformed toxin as in Staphylococcus aureus or Bacillus cereus food poisoning, or toxin secreted in situ by enterotoxigenic E. coli or cholera) drives enterocytes to secrete fluid and electrolytes without necessarily damaging or invading the mucosa, producing large-volume watery diarrhoea with rapid onset and often little fever. Invasive organisms such as Shigella, Campylobacter, Salmonella and enteroinvasive E. coli actually penetrate and damage the colonic mucosa, producing an inflammatory response with fever, cramping and bloody or mucoid stool. Recognising which pattern is present from the history alone points strongly at the class of organism before any test result is back.
Educational content pending clinical review. Not medical advice.