Armando Hasudungan
Biology and Medicine videos

Gastroenteritis (Infectious Diarrhoea)


Watch Video Gastroenteritis (Paediatric) – Overview



Overview Gastroenteritis continues to cause significant morbidity in developed and developing countries. The most common cause are viral and bacterial including:

  • Norovirus
  • Enteric adenoviruses
  • E-coli
  • Salmonella spp. and Shigella spp.
  • Campylobater jejuni


Diarrhoea: Loose, water like stools that occur with increased frequency and an increased volume of >200g per day
Gastroenteritis: >3 or more loose stools per day for <14 days
Chronic Diarrhoea: Diarrhoea that continue for more than 2 weeks
Malabsorption: Defined as the failure to absorb nutrients
Toddlers Diarrhoea: Clinical syndrome characterised by chronic diarrhoea often with undigested food in the stools of a child who is otherwise well, gaining weight and growing satisfactorily.

Gastroenteritis is usually self-resolving. Parasitic infection are uncommon but can be dangerous.

Signs and Symptoms

Clinical Triad of Gastroenteritis: fever, vomiting, diarrhoea

clinical presentation

It is important to assess state of dehydration because this will tailor treatment. Dehydration can be either mild, moderate or severe.


Differential Diagnosis

Viral Gastroenteritis

  • Rotavirus (most common)
  • Noravirus
  • Adenovirus
  • Hepatitis A, B, C, E

Bacterial Gastroenteritis

  • E-coli
  • Clostridium difficile
  • Salmonella
  • Shigella
  • Campylobacter jejuni
Side note Most bacterial causes of diarrhoea are self-limiting and do not usually require antibiotic therapy.

Parasitic Gastroenteritis

  • Giardia Lamblia
  • E. vermicularis
Watch Video Giardia Lamblia
Watch Video Pin Worms – Enterobius Vermicularis


  • Full Blood Count
  • EUC
  • LFT
  • CRP
  • Enzyme immunoassay
  • PCR
  • Stool culture
  • Blood culture


  • Viral causes – Enzyme immunoassay and latex agglutination
  • Bacterial causes – Stool and Blood culture +/- polymerase chain reaction (PCR)
  • Parasitic causes – Microscopy of stool +/- PCR





  • Dehydration
  • Electrolyte imbalance
  • Acidosis
  • Septicaemia
  • Meningitis


Royal Children Hospital Melbourne