See also

Intravenous Fluids
Maintenance Fluids Calculator
Gastroenteritis
Resuscitation: Care of the seriously unwell child

Key points

1. Weight loss is the best measure of dehydration. Clinicals signs can help estimate the severity of dehydration but are often imprecise
2. If a child is haemodynamically unstable (ie in shock), prompt fluid resuscitation with fluid boluses must be given. Sepsis must be considered
3. Rehydrate enterally (orally or via nasogastric route), unless severe dehydration or shock

Background

Dehydration can occur with many childhood illnesses. The mainstay of treatment is fluid management determined by a combination of the degree of dehydration, maintenance fluid requirements and any ongoing losses

Assessment

Red flag features in Red
The most accurate assessment of degree of dehydration is based on the difference between the pre-morbid body weight (within last 2 weeks) and current body weight (eg a 10 kg child who now weighs 9.5 kg has a 500 mL water deficit and is 5% dehydrated). See Assessment of severity table

When a recent weight is not available, use the history and clinical examination to estimate the degree of dehydration

History

• Take a detailed intake history regarding both food and fluid intake in comparison to normal feeding pattern
• Take a detailed output history regarding urine and stool, similarly in comparison to normal output pattern
• Ask about excessive losses (eg vomiting, frequent urination or diarrhoea)
• Recent use of potentially hypertonic/hypotonic fluids (eg diluted formula or soft drinks, water only, fortified feeds)
• Risk factors for severe dehydration and electrolyte disturbances
• Infants <6 months old
• Gastrointestinal pathology (eg short gut syndrome, ileostomy, colostomy, Hirschsprung disease)
• Cystic fibrosis
• Renal impairment
• Use of diuretics
• Metabolic disorders
• Conditions where dehydration carries a high risk for children
• Complex/cyanotic congenital heart disease (especially with cardiac shunts)
• Slow weight gain
• Immunocompromise
• Use of nephrotoxic medications
• Post-organ transplant
  

Examination

• Obtain vital signs
• Obtain weight
• Assess hydration level based on a combination of signs (see Assessment of severity table below)
• Children with mild dehydration have no clinical signs. They may have increased thirst and/or reduced urine output
• More numerous/pronounced signs indicate greater severity
• For clinical shock, one or more of these signs will be present – reduced conscious state, tachycardia, tachypnoea, hypotension, weak peripheral pulses, mottled/cold peripheries, acidosis
• If in doubt, manage as if dehydration falls into the more severe category

Assessment of severity

Management

Investigations

If only mild to moderate dehydration is present, investigations are not necessary

Check for electrolyte abnormalities and blood glucose level (BGL) in children with:

• intravenous fluid requirements
• severe dehydration
• clinical signs of electrolyte disturbances eg hypertonia, hyperreflexia, convulsions, jittery movements, altered conscious state, irregular heart rate, doughy skin turgor (sign of hypernatremia)
• pre-existing medical conditions that predispose to electrolyte abnormalities (eg renal impairment, cystic fibrosis, metabolic disorders, diuretic use)
• history of hyper or hypotonic fluid administration

Treatment

• For children with mild or moderate dehydration, enteral (oral or NG) rehydration is preferable.  IV fluid rehydration is required in severe dehydration or children who cannot tolerate enteral rehydration
• Replacement of fluids may be rapid in most cases of gastroenteritis but should be slower in other illnesses (eg respiratory infection, diabetic ketoacidosis, meningitis and electrolyte disturbances including hypernatremia)
• After treating shock replace remaining deficit slowly over 24–48 hours. Aim to replace 5% dehydration (not including losses) over 24 hours and then reassess
• Rate of fluid administration should be adjusted according to ongoing clinical reassessment including fluid balance. If electrolytes are deranged, consult senior medical staff and relevant guideline, and consider slower replacement of fluid deficit

Approach to rehydration

1. Assess the degree of dehydration. If severe - see Sepsis
2. Investigate the cause of dehydration
3. Manage any electrolyte or BGL abnormalities
4. Provide rehydration via the appropriate route with close monitoring

Approach to rehydration

Consider consultation with local paediatric team when

• Child presents with shock
• Child has electrolyte disturbance and/or predisposing factors for severe or complicated dehydration

Consider transfer when

• Clinical signs of shock persist after maximum of 40 mL/kg fluid given in boluses. Consider other possible causes of shock (eg sepsis and need for antibiotics) other than dehydration alone
• Severe electrolyte derangement

For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services.

Consider discharge when

• Children with mild dehydration and no serious underlying cause can be discharged with advice on continuing rehydration at home
• Consider a review within 48 hours for young infants

Parent information

Kids Health Info - Dehydration

Additional notes

Neonatal Intravenous Fluid Requirements
Hyponatraemia
Hypernatraemia

Last updated September 2020