Page 59 - 15Diarrhoeaandvomiting

Diarrhoea and vomiting caused by gastroenteritis in children under 5 years

infection do not require antimicrobial therapy, this is not always so. Treatment is indicated
for salmonella gastroenteritis in young infants and in immunocompromised children (see
Chapter 7)
– Enteric infection with enterohaemorrhagic E. coli (mainly E. coli O157:H7) often presents
with bloody diarrhoea. These children are at risk of developing HUS, a life-threatening
condition. Early microbiological diagnosis is therefore important.
– Rarely, children may present with bloody diarrhoea associated with antibiotic-related
pseudomembranous colitis, often due to C. difficile. Here C. difficile toxin may be
detected in the stool.
• It is also reasonable to consider investigating children in whom diarrhoea persists for more
than 7 days, because certain treatable enteric infections (for example, giardiasis) may be
responsible.
• If a child presenting with acute diarrhoea is very ill and the possibility of septicaemia
requires empiric antibiotic therapy, stool microbiological investigation would be indicated.
Some patients with bacterial dysentery (salmonella or shigella) may have bacterial
septicaemia, and stool culture could identify the responsible pathogen.
• Various pathogens requiring antimicrobial treatment, such as Giardia lamblia, shigella and
salmonella (in selected cases), are more commonly identified in patients returning from other
countries. The GDG therefore agreed that stool microbiological testing should be considered
in those with a history of recent overseas travel.
The GDG recognised the importance of providing appropriate and adequate clinical information
to the laboratory, including the clinician’s suspicion of any unusual pathogen, in order to
inform the investigative strategy. Certain organisms require special arrangements for collection
or transport to optimise identification. Particular pathogens may sometimes require a targeted
approach with specific laboratory techniques.
The GDG recognised that within hospitals and other institutions it may be important to gather
data on the specific pathogens responsible for gastroenteritis, but policy on this is outside the
scope of this guideline.

The GDG recognised that the public health authorities have access to local and national
epidemiological data, and have a central role in the management of outbreaks of gastroenteritis.
It is therefore important to discuss with the authority any suspected outbreak of gastroenteritis
and its implications.

Recommendations on stool microbiological investigation in diagnosis
Consider performing stool microbiological investigations if:
• the child has recently been abroad or
• the diarrhoea has not improved by day 7 or
• there is uncertainty about the diagnosis of gastroenteritis.
Perform stool microbiological investigations if:

• you suspect septicaemia or
• there is blood and/or mucus in the stool or
• the child is immunocompromised.
Notify and act on the advice of the public health authorities if you suspect an outbreak of
gastroenteritis.
If stool microbiology is performed:
• collect, store and transport stool specimens as advised by the investigating laboratory
• provide the laboratory with relevant clinical information.
3.2.2 Other laboratory investigations

The GDG examined evidence regarding the potential value of various blood tests in distinguishing
bacterial from viral gastroenteritis. As discussed earlier, this might be important for clinical
management in some patients.

34