Gastroenteritis (Infectious Diarrhoea)

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

Definition

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.

Watch Video Gastroenteritis (Paediatric) – Overview

Clinical Manifestation

Clinical Triad of Gastroenteritis: fever, vomiting, diarrhoea.

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

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

Investigations

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

Diagnosis

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

Complications and Prognosis

Complications

  • Dehydration
  • Electrolyte imbalance
  • Acidosis
  • Septicaemia
  • Meningitis

References

Royal Children Hospital Melbourne

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