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Acute Diarrhoea

Increased frequency and water content of stools than is normal for the individual.

Usually: > 3 stools per day


Watery, mucoid, dysenteric


Infective, non-infective

Diarrhoea can be categorized as:

Acute: less than 7 – 10 days

Persistent: More than 7 – 10 days

Chronic: More than 14 – 21 days

(Persistent diarrhoea often a prolonged course of acute insult – different management)

Acute Infective Diarrhoea


Virus  (commonest: Rotavirus)

Bacteria –   Invasive




Mechanisms of acute diarrhoea


eg  Lactose intolerance


eg Cholera

•Mixed secretory-osmotic

eg  Rotavirus

•Mucosal inflammation

eg  Invasive bacteria

•Motility disturbance

Pathogenesis of Diarrhoea

Depends on pathogen

VIRUS  DIARRHOEA (e.g. Rotavirus)

  1. Effect on villus structure and function
  2. Enzyme damage
  3. Significant effect on digestion and absorption
  4. Secretion-absorption imbalance

Bacterial Diarrhoea

•without mucosal injury

mediated by:

  • Enterotoxins
  • Adhesins

•with mucosal injury

mediated by:

  • Adhesins
  • Invasins
  • Cytotoxins

Effects of Diarrhoea


•Biochemical disturbances:

  1. Sodium, Potassium
  2. Metabolic acidosis
  3. Blood glucose
  4. Uraemia


•Severe gut damage : ileus, NEC, PLE

Clinical patterns

•Some associated features depend on pathogen:

  1. Rotavirus
  2. Invasive bacteria
  3. Toxigenic bacteria

•Fever, abdominal pain, early or late vomiting, other symptoms

•Frequency of bacterial or protozoal pathogens — In a review of more than 30,000 stool cultures performed at 10 hospitals in the United States from 1990 to 1992, a bacterial pathogen was identified in 5.6 percent . The frequency of the most common bacterial pathogens were:

•Campylobacter — 2.3 percent (42 percent of isolates)

•Salmonella — 1.8 percent (32 percent of isolates)

•Shigella — 1.1 percent (19 percent of isolates)

•E. coli O157:H7, the major enterohemorrhagic strain — 0.4 percent overall (7 percent of isolates) but much more common in visibly bloody isolates (7.8 versus 0.1 percent in specimens without visible blood).


•Norovirus — Over one-third of outbreaks of nonbacterial gastroenteritis in the United States have been associated with noroviruses



•  Astrovirus


•Cryptosporidium — Cryptosporidium is the most common parasitic cause of acute foodborne diarrhea in the United States, accounting for 8 percent of cases



• Entamoeba histolytica

Management of diarrhoea

•Replace the fluids and electrolytes which are lost

•Drug therapy has very little place

  1. Antibiotic
  2. Antisecretory
  3. Antimotility

•Nutritional management

•Follow-up to ensure recovery

Indications for diagnostic evaluation

•Profuse watery diarrhea with signs of hypovolemia

•Passage of many small volume stools containing blood and mucus

•Bloody diarrhea

•Temperature ≥38.5ºC (101.3ºF)

•Passage of ≥6 unformed stools per 24 hours or a duration of illness >48 hours

•Severe abdominal pain

•Recent use of antibiotics or hospitalized patients

•Diarrhea in the elderly (≥70 years of age) or the immunocompromised

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Chronic Diarrhoea

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