Page 47 - 15Diarrhoeaandvomiting

Diarrhoea and vomiting caused by gastroenteritis in children under 5 years

• Diarrhoea is an alteration in normal bowel movement characterised by an increase in the
water content, volume or frequency of stools. A decrease in consistency (i.e. soft or liquid)
and an increase in frequency of bowel movements to three or more stools per day have often
been used as a definition for epidemiological investigations. 37
• In diarrhoea, stools contain more water than normal – they are also called loose or watery
stools. They may also contain blood, in which case the diarrhoea is called dysentery. Acute
diarrhoea starts suddenly and may continue for several days. It is caused by infection of the
bowel. 38
There is less variation regarding definitions of vomiting. It has been defined as the ejection of
gastric contents up to and out of the mouth, brought about by a forceful contraction of the
abdominal muscles and diaphragm. 39
For the purpose of this guideline, the GDG thus decided to use the following definitions:

‘Diarrhoea refers to the passage of liquid or watery stools. In most cases there is an associated
increase in stool frequency and volume.’
‘Vomiting is the forceful ejection of the stomach contents up to and out of the mouth.’

The GDG considered that, in children with gastroenteritis, the occurrence of diarrhoea is readily
apparent from the sudden change in stool consistency to loose or watery stools. It is often
associated with an increase in stool frequency, although this may not yet be evident at the time
of presentation. Vomiting is partly a voluntary action and partly an involuntary reflex, and is
characterised by the forceful ejection of gastric contents up to and from the mouth. Regurgitation
is common in infants but is a recurring phenomenon and so can usually be distinguished from
sudden onset vomiting due to gastroenteritis.

Recommendation on clinical diagnosis

Suspect gastroenteritis if there is a sudden change in stool consistency to loose or watery
stools, and/or a sudden onset of vomiting.

Clinical question
What is the usual duration of diarrhoea and vomiting in children with gastroenteritis?

It was important to establish the usual duration of vomiting and diarrhoea in children with
gastroenteritis. Persistence of diarrhoea for a longer period of time than expected might be
an important pointer to an alternative diagnosis, for example a non-infectious gastrointestinal
disorder such as coeliac disease. This information would also be important, however, when
advising parents about the likely outcome of the illness, and how soon recovery might reasonably
be expected.

Evidence overview
Many observational studies identified during the literature search did not provide data on the
duration of diarrhoea and vomiting in children or they failed to differentiate between whether
the reported duration was prior to study entry or during the study period. In other studies, some
children were given treatment but the authors failed to provide information separately for the
group which did not receive treatment. Hence information to answer this question was obtained
predominantly from control subjects in RCTs. A total of 11 studies were included, six of which
provided information on the duration of diarrhoea and five on vomiting. Two of these 11 studies
were conducted in the UK.
Of the studies relevant to diarrhoea, five were conducted in a hospital setting and one in a primary
care setting. Data on the mean duration of diarrhoea were obtained from the control subjects in
four RCTs 40–43 conducted in Poland, Israel, Colombia and South Africa. The sample size in these
RCTs ranged from 28 to 120. Further information was obtained from a cross-sectional study from
Kuwait, in which almost 50% of the children (n = 595) had bacterial infections. Unfortunately,
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the data in the Kuwait study was presented without standard deviation values. The primary-care-
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based study was a small RCT from Denmark (n = 19) that recruited participants with acute
diarrhoea from a day-care centre. The results are presented in Table 3.1.

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