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
Check
- Foreign travel, constitutional symptoms, general health (immunosuppression, diabetes), GI surgery, T4
- Red flags, hydration, abdo. exam. (peritonism), wt loss
- Duration (see table)
| 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, E. coli
Fever
- ½ 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)