Page 46 - 15Diarrhoeaandvomiting

3 Diagnosis

Many children experience brief episodes of vomiting and diarrhoea due to mild gastroenteritis and
are managed by their parents at home. Parents may not approach a healthcare professional at all.
However, many do seek advice either ‘remotely’ (for example, NHS Direct) or through a face-to-
face consultations. When children present to a healthcare professional, it is important to establish
whether or not they truly have diarrhoea or vomiting. This chapter reviews the relevant published
evidence and provides recommendations regarding the clinical and laboratory diagnosis of
gastroenteritis. These recommendations are intended to take account of the particular setting in
which the child presents, for example in the community, the general practitioner’s surgery, or the
hospital emergency department.

3.1 Clinical diagnosis

Introduction

The sudden onset of diarrhoea with or without vomiting in a previously well child is usually
due to gastroenteritis. The definition of diarrhoea may seem to be self-evident but, even in well
infants and children, stool frequency and consistency vary considerably. For example, breastfed
infants may have more frequent and softer stools than bottle-fed infants. Even in older children,
confusion may occur – those with overflow faecal incontinence due to constipation are often
mistakenly reported to have diarrhoea.

Vomiting may occur before the onset of diarrhoea. However, vomiting in isolation may be due to
a wide range of other potentially serious conditions. In infants, vomiting must be distinguished
from the normal phenomenon of regurgitation.
Although most children with acute-onset diarrhoea have gastroenteritis, occasionally it may
occur in association with other disorders, such as non-gastrointestinal infections (for example,
pneumonia), and surgical conditions (for example, acute appendicitis). In 2007, 7600 children
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presented to a paediatric emergency unit in England with suspected acute gastroenteritis. Of
these, 60% were discharged for home treatment. A total of 3022 were admitted to an observation
ward, and only 106 of these were subsequently transferred to a medical or surgical ward. Those
children had a range of diagnoses, including gastroenteritis, non-specific abdominal pain,
appendicitis and constipation. Other diagnoses were rare but included such diverse conditions as
non-infective colitis, malabsorption, intestinal obstruction, inguinal hernia and pyloric stenosis.
Even when a presumptive diagnosis of gastroenteritis has been made at the outset, it is important to
reconsider the diagnosis if the subsequent course of the illness is inconsistent with the condition.
This chapter gives recommendations regarding practical definitions for diarrhoea and vomiting,
identifies key clinical pointers to conditions other than gastroenteritis and provides information
on the natural history of the disease.

Clinical question
What definitions of diarrhoea and vomiting have been used previously?

Research studies on the incidence of gastroenteritis have employed various arbitrary definitions
of diarrhoea based on the stool frequency and/or consistency. A change in these variables in
the individual child has also been considered to be an important consideration. Examples of
definitions that have been employed are listed below.
• Diarrhoea is defined as a change in bowel habit for the individual child resulting in
substantially more frequent and/or looser stools. 17
• Diarrhoea in children is the passage of unusually loose or watery stools, usually at least three
times in 24 hours. It is acute if it has persisted for less than 10–14 days. 20

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