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Dehydration

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  • 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

     

    Mild dehydration (<5%)

    Moderate dehydration (5-9%)
    Signs mildly to moderately abnormal

    Shock (≥10%)

    Signs markedly abnormal

    Conscious state

    Alert and responsive

    Lethargic, irritable

    Reduced conscious state

    Heart rate

    Normal

    Normal/mild tachycardia

    Tachycardia

    Breathing

    Normal

    Increased respiratory rate

    Increased respiratory rate
    Deep acidotic breathing

    Blood pressure

    Normal

    Normal

    Hypotension

    Skin colour

    Normal

    Normal

    Pale or mottled

    Extremities

    Warm

    Warm

    Cold

    Peripheral pulses

    Normal

    Normal

    Weak

    Eyes & fontanelle

    Not sunken

    Sunken

    Deeply sunken

    Mucous membranes

    Moist

    Dry

    Dry

    Skin turgor

    Instant recoil

    Mildly decreased

    Decreased

    Central capillary refill time

    Normal

    Prolonged

    Markedly prolonged

    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

    Dehydration

    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

  • Reference List

    1. Cellucci MF 2019. Dehydration in Children, MSD Manual; viewed 21 April 2020, https://www.msdmanuals.com/professional/pediatrics/dehydration-and-fluid-therapy-in-children/dehydration-in-children#.
    2. Powers KS. Dehydration: Isonatremic, Hyponatremic, and Hypernatremic Recognition and Management. Pediatr Rev. 2015;36(7):274-83; quiz 84-5.
    3. Santillanes G, Rose E. Evaluation and Management of Dehydration in Children. Emerg Med Clin North Am. 2018;36(2):259-73.
    4. Steiner MJ, DeWalt DA, Byerley JS. Is this child dehydrated? JAMA. 2004;291(22):2746-54.