3.1. 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.

If you suspect gastroenteritis, ask about:

• recent contact with someone with acute diarrhoea and/or vomiting and
• exposure to a known source of enteric infection (possibly contaminated water or food) and
• recent travel abroad.

Be aware that in children with gastroenteritis:

• diarrhoea usually lasts for 5–7 days, and in most it stops within 2 weeks
• vomiting usually lasts for 1–2 days, and in most it stops within 3 days.

Consider any of the following as possible indicators of diagnoses other than gastroenteritis:

• fever:

  –

  temperature of 38 °C or higher in children younger than 3 months

  –

  temperature of 39 °C or higher in children aged 3 months or older

• shortness of breath or tachypnoea
• altered conscious state
• neck stiffness
• bulging fontanelle in infants
• non-blanching rash
• blood and/or mucus in stool
• bilious (green) vomit
• severe or localised abdominal pain
• abdominal distension or rebound tenderness.

3.2. Laboratory investigations

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.

Perform a blood culture if giving antibiotic therapy.

In children with Escherichia coli O157:H7 infection, seek specialist advice on monitoring for haemolytic uraemic syndrome.

4.1. Clinical assessment

During remote or face-to-face assessment ask whether the child:

• appears unwell
• has altered responsiveness, for example is irritable or lethargic
• has decreased urine output
• has pale or mottled skin
• has cold extremities.

Recognise that the following are at increased risk of dehydration:

• children younger than 1 year, particularly those younger than 6 months
• infants who were of low birthweight
• children who have passed more than five diarrhoeal stools in the previous 24 hours
• children who have vomited more than twice in the previous 24 hours
• children who have not been offered or have not been able to tolerate supplementary fluids before presentation
• infants who have stopped breastfeeding during the illness
• children with signs of malnutrition.

Use Table 4.6 to detect clinical dehydration and shock.

Suspect hypernatraemic dehydration if there are any of the following:

• jittery movements
• increased muscle tone
• hyperreflexia
• convulsions
• drowsiness or coma.

4.2. Laboratory investigations for assessing dehydration

Do not routinely perform blood biochemical testing.

Measure plasma sodium, potassium, urea, creatinine and glucose concentrations if:

• intravenous fluid therapy is required or
• there are symptoms and/or signs that suggest hypernatraemia.

Measure venous blood acid–base status and chloride concentration if shock is suspected or confirmed.

5.1. Primary prevention of dehydration

In children with gastroenteritis but without clinical dehydration:

• continue breastfeeding and other milk feeds
• encourage fluid intake
• discourage the drinking of fruit juices and carbonated drinks, especially in those at increased risk of dehydration
• offer oral rehydration salt (ORS) solution as supplemental fluid to those at increased risk of dehydration.

5.2. Treating dehydration

Use ORS solution to rehydrate children, including those with hypernatraemia, unless intravenous fluid therapy is indicated.

5.3. Optimal composition and administration of oral fluids

In children with clinical dehydration, including hypernatraemic dehydration:

• use low-osmolarity ORS solution (240–250 mOsm/l)^** for oral rehydration therapy
• give 50 ml/kg for fluid deficit replacement over 4 hours as well as maintenance fluid
• give the ORS solution frequently and in small amounts
• consider supplementation with their usual fluids (including milk feeds or water, but not fruit juices or carbonated drinks) if they refuse to take sufficient quantities of ORS solution and do not have red flag symptoms or signs (see Table 4.6)
• consider giving the ORS solution via a nasogastric tube if they are unable to drink it or if they vomit persistently
• monitor the response to oral rehydration therapy by regular clinical assessment.

5.4. Intravenous fluid therapy

Use intravenous fluid therapy for clinical dehydration if:

• shock is suspected or confirmed
• a child with red flag symptoms or signs (see Table 4.6) shows clinical evidence of deterioration despite oral rehydration therapy
• a child persistently vomits the ORS solution, given orally or via a nasogastric tube.

Treat suspected or confirmed shock with a rapid intravenous infusion of 20 ml/kg of 0.9% sodium chloride solution.

If a child remains shocked after the first rapid intravenous infusion:

• immediately give another rapid intravenous infusion of 20 ml/kg of 0.9% sodium chloride solution and
• consider possible causes of shock other than dehydration.

Consider consulting a paediatric intensive care specialist if a child remains shocked after the second rapid intravenous infusion.

When symptoms and/or signs of shock resolve after rapid intravenous infusions, start rehydration with intravenous fluid therapy

If intravenous fluid therapy is required for rehydration (and the child is not hypernatraemic at presentation):

• use an isotonic solution such as 0.9% sodium chloride, or 0.9% sodium chloride with 5% glucose, for fluid deficit replacement and maintenance
• for those who required initial rapid intravenous fluid boluses for suspected or confirmed shock, add 100 ml/kg for fluid deficit replacement to maintenance fluid requirements, and monitor the clinical response
• for those who were not shocked at presentation, add 50 ml/kg for fluid deficit replacement to maintenance fluid requirements, and monitor the clinical response
• measure plasma sodium, potassium, urea, creatinine and glucose at the outset, monitor regularly, and alter the fluid composition or rate of administration if necessary
• consider providing intravenous potassium supplementation once the plasma potassium level is known.

If intravenous fluid therapy is required in a child presenting with hypernatraemic dehydration:

• obtain urgent expert advice on fluid management
• use an isotonic solution such as 0.9% sodium chloride, or 0.9% sodium chloride with 5% glucose, for fluid deficit replacement and maintenance
• replace the fluid deficit slowly–typically over 48 hours
• monitor the plasma sodium frequently, aiming to reduce it at a rate of less than 0.5 mmol/l per hour.

Attempt early and gradual introduction of oral rehydration therapy during intravenous fluid therapy. If tolerated, stop intravenous fluids and complete rehydration with oral rehydration therapy.

5.5. Fluid management following dehydration

After rehydration:

• encourage breastfeeding and other milk feeds
• encourage fluid intake
• in children at increased risk of dehydration recurring, consider giving 5 ml/kg of ORS solution after each large watery stool. These include:

  –

  children younger than 1 year, particularly those younger than 6 months

  –

  infants who were of low birthweight

  –

  children who have passed more than five diarrhoeal stools in the previous 24 hours

  –

  children who have vomited more than twice in the previous 24 hours.

Restart oral rehydration therapy if dehydration recurs after rehydration.

10.1. Caring for a child with diarrhoea and vomiting at home

Inform parents and carers that:

• most children with gastroenteritis can be safely managed at home, with advice and support from a healthcare professional if necessary
• the following symptoms may indicate dehydration:

  –

  appearing to get more unwell

  –

  changing responsiveness (for example, irritability, lethargy)

  –

  decreased urine output

  –

  pale or mottled skin

  –

  cold extremities

• they should contact a healthcare professional if symptoms of dehydration develop.

Advise parents and carers of children:

• who are not clinically dehydrated and are not at increased risk of dehydration:

  –

  to continue usual feeds, including breast or other milk feeds

  –

  to encourage the child to drink plenty of fluids

  –

  to discourage the drinking of fruit juices and carbonated drinks

• who are not clinically dehydrated but who are at increased risk of dehydration:

  –

  to continue usual feeds, including breast or other milk feeds

  –

  to encourage the child to drink plenty of fluids

  –

  to discourage the drinking of fruit juices and carbonated drinks

  –

  to offer ORS solution as supplemental fluid

• with clinical dehydration:

  –

  that rehydration is usually possible with ORS solution

  –

  to make up the ORS solution according to the instructions on the packaging

  –

  to give 50 ml/kg ORS solution for rehydration plus maintenance volume over a 4 hour period

  –

  to give this amount of ORS solution in small amounts, frequently

  –

  to seek advice if the child refuses to drink the ORS solution or vomits persistently

  –

  to continue breastfeeding as well as giving the ORS solution

  –

  not to give other oral fluids unless advised

  –

  not to give solid foods.

Advise parents and carers that after rehydration:

• the child should be encouraged to drink plenty of their usual fluids, including milk feeds if these were stopped
• they should avoid giving the child fruit juices and carbonated drinks until the diarrhoea has stopped
• they should reintroduce the child’s usual diet
• they should give 5 ml/kg ORS solution after each large watery stool if you consider that the child is at increased risk of dehydration.

Advise parents and carers that:

• the usual duration of diarrhoea is 5–7 days and in most children it stops within 2 weeks
• the usual duration of vomiting is 1 or 2 days and in most children it stops within 3 days
• they should seek advice from a specified healthcare professional if the child’s symptoms do not resolve within these timeframes.

10.2. Preventing primary spread of diarrhoea and vomiting

Advise parents, carers and children that:^***

• washing hands with soap (liquid if possible) in warm running water and careful drying are the most important factors in preventing the spread of gastroenteritis
• hands should be washed after going to the toilet (children) or changing nappies (parents/carers) and before preparing, serving or eating food
• towels used by infected children should not be shared
• children should not attend any school or other childcare facility while they have diarrhoea or vomiting caused by gastroenteritis
• children should not go back to their school or other childcare facility until at least 48 hours after the last episode of diarrhoea or vomiting
• children should not swim in swimming pools for 2 weeks after the last episode of diarrhoea.

Why this is important

Evidence from a systematic review^†† suggests that some symptoms and signs (for example, prolonged capillary refill time, abnormal skin turgor and abnormal respiratory pattern) are associated with dehydration, measured using the accepted ‘gold standard’ of the difference between pre-hydration and post-hydration weight. However, 10 of the 13 included studies were not blinded and had ill-defined selection criteria. Moreover, all these studies were conducted in secondary care where children with more severe dehydration are managed.

Most children with gastroenteritis can and should be managed in the community^‡ but there is a lack of evidence to help primary care healthcare professionals correctly identify children with more severe dehydration. Symptoms and signs that researchers may wish to investigate include overall appearance, irritability/lethargy, urine output, sunken eyes, absence of tears, changes in skin colour or warmth of extremities, dry mucous membranes, depressed fontanelle, heart rate, respiratory rate and effort, character of peripheral pulses, capillary refill time, skin turgor and blood pressure.

Why this is important

Oral rehydration therapy is normally preferable to intravenous fluid therapy for rehydration in children with gastroenteritis. However, some children may not tolerate oral rehydration therapy, either because they are unable to drink ORS solution in adequate quantities or because they persistently vomit. In such cases, ORS solution could be administered via a nasogastric tube, rather than changing to intravenous fluid therapy. This overcomes the problem of ORS solution refusal. Continuous infusion of ORS solution via a nasogastric tube might reduce the risk of vomiting. A well-conducted randomised controlled trial is needed to assess the cost effectiveness, safety and acceptability of rehydration using nasogastric tube administration of ORS solution compared with intravenous fluid therapy.

Why this is important

Most children with clinical dehydration should be treated with oral rehydration therapy, but some require intravenous fluid therapy because they are shocked or they cannot tolerate oral rehydration therapy. Rehydration with oral rehydration therapy is usually carried out over a period of 4 hours. Rehydration with intravenous fluid therapy has traditionally been undertaken slowly – typically over 24 hours. The National Patient Safety Agency has advised^**** that intravenous fluid deficit replacement should be over 24 hours or longer. Consequently, children will remain dehydrated and in hospital for a prolonged period. The WHO recommends that intravenous rehydration should be completed in 3–6 hours.^††† Many experts now support rapid intravenous rehydration, suggesting that it allows oral fluids to be starter earlier and can shorten the duration of hospital treatment. Randomised controlled trials are needed urgently to examine the safety and cost-effectiveness of rapid intravenous rehydration regimens compared with slow intravenous rehydration.

Why this is important

Several randomised controlled trials have shown that in children with persistent vomiting during oral rehydration therapy, administration of oral ondansetron, an anti-emetic agent, can increase the likelihood of successful oral rehydration. However, in two of these there was evidence suggesting that diarrhoea was more pronounced in those given ondansetron than in those in the placebo groups. In one, in children given ondansetron, the number of stools passed during the rehydration phase was significantly greater, and in the other the number of stools passed in the first and second 24 hour period after rehydration was significantly greater. In those studies, diarrhoea was not a primary outcome, and it was reported as an adverse event. The reliability of the finding was therefore somewhat uncertain. If ondansetron does worsen diarrhoea it would be crucially important to determine the clinical significance of this effect, for example in relation to the risk of dehydration recurring or re-admission to hospital. If ondansetron is shown to be both effective and safe in secondary care then studies should also be undertaken to evaluate its use in primary care.

Why this is important

The available studies of probiotic therapy frequently report benefits, particularly in terms of reduced duration of diarrhoea or stool frequency. However, most of the published studies have methodological limitations. Moreover, there is great variation in the specific probiotics evaluated and in the treatment regimens used. Many of these studies were conducted in developing countries where the response to probiotic therapy may differ. Good-quality randomised controlled trials should be conducted in the UK to evaluate the effectiveness and safety of specific probiotics, using clearly defined treatment regimens and outcome measures.