Acute Diarrhoea

Introduction to Acute Diarrhoea

Acute diarrhoea is defined as at least 3 liquid stools per day for less than 2 weeks.

Diarrhoea generally is a common clinical condition worldwide, particularly in developing countries.

It accounts for a significant morbidity and mortality, especially in children.

Infective agents are recognized in about 70% of cases and are transmitted by the faeco-oral route.

Viruses (particularly Rotavirus) are responsible for over 70% of it in children below 2 years.

Many bacteria and some parasites are also important aetiologic agents, particularly in adolescents and adults.

Endemic and epidemic presentations can occur.

Contamination of food and water by bacterial toxins also lead to acute diarrhoea, sometimes with associated vomiting (i.e. food poisoning).
This is usually self-limiting.

Symptoms of Acute Diarrhoea

  • Watery stools of varying volumes
  • sometimes with vomiting: this is the commonest presentation, and suggests pathology in the small intestine.
  • Bloody mucoid stools: suggests disease in the colon
  • Fever, abdominal pain and dehydration
  • Fast and small volume pulse with low blood pressure: indicates significant fluid loss

Complications of Diarrhoea

  • Hypovolaemic shock with multiple organ failure
  • Septicaemia
  • Intestinal perforation
  • Gastro-intestinal bleeding
  • Paralyticileus

Differential diagnoses

Non-infectious diarrhoea e.g. drug-induced

  • Gut allergy (e.g. gluten)..
  • Psychogenic stress.
  • Metabolic and endocrine causes (e.g. thyrotoxicosis, uraemia, diabetes mellitus).


  • Stool examination including microscopy, culture and sensitivity
  • Full Blood Count
  • Urea, Electrolytes and Creatinine Serology (e.g. Widal test)

Diarrhoea treatment


  • Achieve adequate hydration.
  • Eliminate infectious agent
  • Treat complications

Drug treatment for diarrhoea

Rehydrate with:

Oral Rehydration Therapy ORT (low osmolarity) for mild to moderate dehydration

  • 500 mL orally over 2-3 hours, 3-4 times daily

Intravenous sodium chloride 0.9%

  • 1 litre 2-6 hourly for moderate-to-severe dehydration.
  • Alternate with Darrow’s solution depending on serum potassium


  • Use of zinc supplementation
  • 20 mg per day for 10-14 days
  • Under 6 months old: 10 mg per day

Specific anti-infective agents for infectious diarrhoeas. e.g. metronidazole for amoebiasis, giardiasis

Supportive measures

Monitor fluid intake/output

Notable adverse drug reactions

Heart failure: from over hydration. Initial increase in diarrhoea with ORT: this is self limiting.

Hyperkalaemia: from excessive use of potassium-containing fluids


  • Provide access to safe drinking water
  • Sanitary disposal of human waste
  • Personal hygiene: hand-washing, care in food-handling


  1. Medecins San Frontieres: Acute Diarrhoea Treatment Guideline
  2. American Family Physician: Acute Diarrhoea

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