=====Diarrhoea=====
A change in stool consistency to watery or loose, with >3 episodes or >200g stool in 24/24.
  *Acute: <14 days
  *Persistent: 14-30 days
  *Chronic: >30 days

Differential Diagnosis for diarrhoeal illness is broad. Consider:
  *mesenteric ischemia
  *appendicitis, bowel obstruction, volvulus, diverticular disease,
  *fecal impaction/incontinence
  *GI cancers, GI bleed
  *IBD, toxic megacolon
  *hyperthyroidism, pancreatic insufficiency
  *lactose intolerance, etc.

^Infectious: 80-85% ^|^Non-infectious: 10-15% |
^Viral\\ 60% ^Bacterial\\ 20-25% ^Parasitic\\ 5% |::: |
|• Norovirus\\ • Rotavirus (kids) |• E Coli, Campylobacter\\ • Salmonella, Shigella| |• Toxins\\ • medication side effects\\ • osmotic food and drink\\ • underlying GI pathology (IBD, malignancy, etc) |

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^Small bowel ^Large bowel |
|• more likely viral\\ • watery, large volume stools.\\ • Often associated with abdominal cramping, bloating, and gas.\\ • Less commonly febrile. |• more likely bacterial\\ • frequent small volume stools.\\ • may be bloody or mucoid.\\ • Often associated with painful bowel movements.\\ • Fever common |

===High risk factors===

  *Severe abdominal pain
  *Bloody or mucoid diarrhoea
  *Extremes of age (e.g. >70 years old or <3 months old)
  *Known HIV or other immuno-compromise
  *Known inflammatory bowel disease
  *Co-morbidities exacerbated by hypovolaemia
  *Pregnancy

<WRAP info round>The majority of diarrhoea is non-bloody. The presence of blood suggests:
  *shiga-toxin producing E Coli (O157:H7) and Shigella
  *occasionally - campylobacter and salmonella
  *non-infectious causes - ischaemia, IBD.
</WRAP>
===Management of bloody diarrhoea===
  *Antibiotic use is generally not indicated unless a relevant pathogen has been isolated
  *Antibiotic use may prolong faecal excretion and usually doesn't affect course of diarrhoea significantly
  *Antibiotic use in patients with E Coli O157:H7 is associated with an increased risk of Haemolytic Uraemic Syndrome (HUS)
  *anti-motility drugs including narcotics are also generally not indicated, especially in patients with E Coli O157:H7 due to the risk of HUS and the neurological complications associated with HUS
  *priority is fluid resuscitation and correction of metabolic abnormalities when relevant
  *children with bloody diarrhoea should be admitted

===Shiga toxin===
  *one of the most potent bacterial toxins known.
  *found in Shigella dysenteriae type 1 and some serogroups of E coli
  *causes bloody diarrhoea and sometimes haemolytic uraemic syndrome (HUS)
  *usually from contaminated food or water, though occasionally be passed person-to-person

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{{:wiki:gastroenterology:cuh_gastroenteritis.png?500| }}
{{ :wiki:gastroenterology:cuh_c_difficile.png?500|}}

==References include==
https://coreem.net/core/diarrhea/\\ 
[[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270005/|Shiga toxin]]\\ 
[[https://www.gastrojournal.org/article/S0016-5085(09)00344-8/fulltext|Am Gastro J Bloody diarrhoea review 2009]]\\