Gastroenteritis in Children

Last Updated on by frcemuser



  • Rotavirus (most common)
  • Norovirus
  • Adenovirus


  • Campylobacter
  • Salmonella
  • Shigella


  • Cryptosporidium

Clinical assessment – Degree of dehydration

Your initial clinical assessment will stratify the child into minimal, mild to moderate, or severe dehydration (see Table ). This translates roughly into <5% loss in body weight, 5-10% loss of body weight and >10% loss of body weight and is essential for guiding treatment.

Fluid Management

Choice of fluid

  • For oral or NG rehydration, reduced osmolarity oral rehydration solution (ORS) is recommended (50/60mmol/L of sodium) . Lemonade, sports drinks or homemade ORS are not appropriate.
  • For IV rehydration, during the initial phase of restoring fluid volume, isotonic fluid (usually 0.9% NaCl) is recommended. Hypotonic solutions are associated with an increased risk of developing hyponatraemia .
  • Once fluid volume has been restored, glucose should be added to the saline solution in the maintenance phase of IV rehydration (0.9% NaCl with 5% dextrose).

Volume and rate of fluid replacement- Calculating deficit and maintenance

Replacing the child’s deficit

  • Estimate if the child has a 5% or 10% deficit (see the assessment of dehydration section above)
  • Estimated deficit (in ml) is 5% (or 10%) X childs weight in kg X 10

Replacing child’s daily maintenance requirements (Holliday Segar method)

  • 100ml/kg for first 10kg of body weight, then
  • 50ml/kg for next 10kg of body weight, then
  • 20ml/kg for each subsequent kg of body weight
  • Divide this total by 24 to get the hourly maintenance fluid requirements

The total fluid replacement rate

  • Decide over how many hours you want to replace the estimated deficit and add the calculated hourly maintenance requirement

Management – Clinical Shock

Resuscitation phase

  • Ensure patient airway, give high flow oxygen
  • Obtain urgent IV access
  • Measure baseline U&Es, blood glucose, and venous blood gas
  • Give a fluid bolus of 20 ml/kg 0.9% saline
  • If remains shocked after the first bolus
  • Give a second bolus
  • Consider other causes for shock
  • If remains shocked after the second bolus
  • Give a further bolus
  • Consider discussion with the pediatric intensive care team

Maintenance phase

  • Once symptoms and signs of shock have resolved
  • Calculate daily maintenance requirement
  • Use 10% estimate for a deficit calculation
  • Consider adding potassium to fluids once serum level is known
  • Monitor clinical and laboratory response to fluid therapy, adjust subsequent fluids as appropriate
  • Discuss with paediatric team

Worked example – Clinical Shock

A 24 kg child responded to a 20 ml/kg fluid bolus and is no longer shocked. What is his initial hourly IV fluid requirement using the standard regime? What type of fluid would you prescribe?


Estimated deficit 10% for this category

Deficit = 10 X 24kg X 10 = 2400 ml

Daily maintenance = (100 ml/kg x 10 kg) + (50 ml/kg x 10 kg) + (20 ml/kg x 4 kg) = 1580 ml

Hourly requirement = (2400 + 1580) / 24 = 165 ml/hour if replacing over 24hrs

Consider adding potassium once serum levels are known


Management – Clinical Dehydration

Initial management

  • Initial management is oral rehydration-low osmolarity oral rehydration solution
  • Continue to breastfeed (if applicable)
  • Calculate deficit (estimated at 5% in this category of the child)

Calculate maintenance fluid requirements

  • Replace over 4 hours in frequent but small amounts (total replacement rate is usually 10-20ml/kg/hr)
    Monitor response to oral fluid

Child refuses to take ORS / continues vomiting

  • Consider NGT placement if the child is unable to drink and/or vomits persistently
  • IV rehydration and/or admission may be required if symptoms do not settle

Worked example -Clinical Dehydration

What is the hourly ORS requirement for a 24 kg child who is clinically dehydrated?


Estimated deficit 5% for this category; fluids will be replaced over 4 hours

Deficit = 5 X 24kg X 10 = 1200 ml

Daily maintenance = (100 ml/kg x 10 kg) + (50 ml/kg x 10 kg) + (20 ml/kg x 4 kg) = 1580 ml in 24 hrs

4 hour maintenance = (1580/24) X 4 = 263ml

Hourly requirement for 4 hours of rehydration = (1200 + 263) 4 = 365 ml/hour


Children are at increased risk of dehydration

  • Young age (<1 year of age and especially < 6 months)
  • Infants who were of low birth weight
  • Those with signs of malnutrition Frequent symptoms (>5 diarrhoeal stools or >2 vomits within the previous 24 hours)
  • Those who are not offered supplementary fluids or stopped breastfeeding prior to presentation

Discharge criteria

  • If the oral fluid is tolerated over the first hour, consider the child for discharge home
  • Reassure parents or carers that oral rehydration is usually possible

Provide verbal advice to:

  • Complete the remainder of the 4-hour fluid challenge at home
  • Administer the fluid in small, frequent amounts
  • Breastfeeding should be continued throughout rehydration
  • An age-appropriate diet should be started during or after initial rehydration (4-6 hours); dilution of the formula is usually unnecessary
  • Seek advice if the child refuses to drink or vomits persistently


Management – No Clinical Dehydration

The aim is to prevent dehydration

  • Discharge home from the ED
  • Reassure parents and carers that most cases can be safely managed at home

Provide verbal advice to

  • Continue breast feeds and other milk feeds
  • Encourage fluid intake
  • Discourage fruit juices and carbonated drinks
  • If increased risk of dehydration, offer low osmolality ORS (i.e. Dioralyte , Electrolade ) as a supplemental fluid
  • Seek advice from a healthcare professional if symptoms of dehydration develop
    • Appearing to get more unwell
    • Changing responsiveness (e.g. irritability or lethargy)
    • Decreased urine output
    • Pale or mottled skin
    • Cold extremities
  • Advise on the typical duration of symptoms and to seek advice if they do not resolve within these time frames
    • Vomiting: 1-2 days, most stop within 3 days
    • Diarrhea: 5-7 days, most stop within 2 weeks


Hypernatraemic Dehydration

Consider in

  • Child <6 months old
  • Doughy skin
  • Tachypnoea
  • Jitteriness

Other neurological signs: increased muscle tone, hyperreflexia, convulsions, drowsiness, coma


  • Resuscitate with the usual boluses of 20ml/kg 0.9% NaCl if child is shocked.
  • Thereafter, rapid correction can be dangerous ideally oral rehydration should be used
  • Obtain baseline U&Es and blood glucose
  • If IV fluids are required:
  • Obtain urgent expert advice on fluid management
  • Commence isotonic fluids for deficit correction and maintenance (0.9% saline and 5% glucose)
  • Rehydrate slowly (normally over 48 hours)
  • Monitor serum sodium level frequently
  • Aim for a reduction of less than 0.5 mmol Na+/L per hour
  • Gradually attempt to introduce oral fluids early
  • If tolerated, complete rehydration with oral fluid therapy


Management – Additional Therapies

The majority of cases of paediatric gastroenteritis are viral and antibiotics are not required.

Antibiotics should only be given in cases of:

  • Suspected or confirmed septicaemia
  • Extra-intestinal spread of bacterial infection
  • Confirmed shigellosis, Vibrio Cholera, dysenteric Campylobacter or moderate-severe Clostridium difficile
  • Salmonella infection in infants or immunocompromised children only
  • Specialist advice should be sought in children who have recently returned from abroad

Advice should be sought in cases of children with Escherichia coli O157:H7 infection regarding monitoring for haemolytic uraemic syndrome


Subsequent evidence showed that a single oral dose of ondansetron helps to stop vomiting and reduce the number needing IV fluid and admission



Stool Culture
Stool cultures should not be sent routinely.

Consider sending a stool sample for microscopy, culture and sensitivity (MC&S) if :

  • The child has recently been abroad to an at-risk area
  • The diarrhoea has not improved by day 7
  • There is uncertainty regarding the diagnosis

A sample should be sent if:

  • Septicaemia is suspected
  • There is blood and/or mucus in the stool
  • The child is immunocompromised

In the case of an outbreak, notify and act on the advice of the public health authorities as to what samples should be sent.

Blood biochemistry should not be carried out routinely.

Consider measuring laboratory U&Es, venous blood gas and blood glucose if:

  • Starting intravenous rehydration
  • Hypernatraemic dehydration is suspected
  • The child is severely dehydrated / clinically shocked
  • The child is mild to moderately dehydrated but the examination findings are not consistent with gastroenteritis as the cause

Alternative diagnosis should be excluded 

  • infections: meningitis, septicemia, urinary tract infection, pneumonia
  • Acute surgical abdominal conditions: appendicitis, volvulus, intussusception
  • Non-infective gastroenterological conditions: inflammatory bowel, coeliac disease, malabsorption, overflow constipation
  • Antibiotic-associated diarrhea: including Clostridium difficile
  • Endocrine: DKA

Clinical features should prompt you to consider an alternative diagnosis

  • 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 consciousness
  • 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
  • vomiting lasting more than 24 hours without diarrhoea
  • persistent diarrhoea (more than 10 days)

Public health considerations

Parents and carers should be advised how to prevent spread of the infection:

  • Washing hands in warm, soapy water after going to the toilet, changing nappies and preparing, serving or eating food
  • Towels used by the infected child should not be shared
  • The child should not return to school (or childcare facility) until asymptomatic for 48 hours
  • The child should not swim in a public pool until asymptomatic for 2 weeks
  • Notify and act on the advice of the public health authorities if you suspect an outbreak of gastroenteritis


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