Acute diarrhoea in adults



Red Flags

  • Blood in the stool
  • Recent hospital treatment or antibiotics
  • Nocturnal diarrhoea or incontinence
  • Co-morbidities (esp. HIV, diabetes)

Commonest causes acute (< 4 weeks) diarrhoea

  • Viruses (rotavirus 8%, norovirus)
  • Campylobacter (12%)
  • Non- infective causes less common (Drugs, alcohol, anxiety, IBD)

Check

  • Foreign travel, constitutional symptoms, general health (immunosuppression, diabetes), GI surgery, T4
  • Red flag symptoms, hydration status, abdominal examination (peritonism), weight loss
  • Duration (see right)
Agent Typical duration diarrhoea
Rotavirus 3- 8 days
Norovirus 2 days
Campylobacter, Salmonella 2 - 7 days
Giardia > 1 week

Travel

  • Possibility of bacterial, viral, or protozoal infection
  • 25-50% of cases of "travellers’ diarrhoea" no specific agent
  • Stool micro C&S ( eggs and parasites) highly sensitive and specific
  • Commonest id on microscopy
    • Amoeba, Giardia, Shigella, Salmonella
    • Yersinia, Campylobacter, Escherichia coli

Fever

  • 1/2 of half of patients with infective diarrhoea
  • esp. Campylobacter and rotavirus infections

Headache

  • Common in rotavirus infection

CRP

  • CRP higher in bacterial than viral
  • Less useful (tends to be higher in Crohn's ) in IBD

Blood in the stool

  • Campylobacter (40% cases have blood)
  • Toxogenic E coli
  • Salmonella
  • Shigella
  • Yersinia

Rarely

  • Lactose intolerance
  • Inflammatory bowel disease
  • Coeliac disease
    • Tissue transglutaminase antibody (tTgA) test
  • Colorectal cancer (Hb, ESR, CRP, colonoscopy)

Content by Dr Íomhar O' Sullivan 22/06/2009 From BMJ article June 2009 Last review Dr ÍOS 13/12/21.