Pyloric stenosis

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    This guideline has been adapted for statewide use with the support of the Victorian Paediatric Clinical Network

  • See also

    IV Fluids

    Key points

    1. Correction of fluid deficit, electrolyte and acid base abnormalities is the priority
    2. Following fluid resuscitation (if required) 0.9% Sodium Chloride with 5% glucose and 20mmol/l Potassium Chloride should be used for replacement of deficit and ongoing fluid maintenance.
    3. Surgical correction may be safely delayed until correction of fluid deficit, electrolyte and acid base abnormalities.  


    • Hypertrophic Pyloric Stenosis (HPS) usually presents between 2 and 6 weeks of chronological age with progressive non-bilious vomiting.
    • There may be a parental history of HPS (especially if mother affected)



    • Vomiting
      • Recurrent and progressively more forceful. May be projectile.
      • Soon after feeding
      • Non-bilious
      • Blood stained in up to 10% of cases
    • Often hungry afterwards
    • Weight loss or inadequate weight gain


    • Dehydration:
      • Assess degree of dehydration (see dehydration guideline)
      • Weigh and plot on growth chart with previous weights if available
    • Visible Gastric peristalsis (may be more obvious following a feed)
    • Pyloric mass
      • Located at the lateral edge of the rectus abdominis muscle in the right upper quadrant
      • Best felt from the left side with the infant settled and supine.
      • May be difficult to palpate. May require repeated examinations or to wait for several minutes with hand on abdomen to feel.


    • Capillary or venous blood gas with electrolytes and glucose
    • Hypochloraemic Hypokalaemic Metabolic Alkalosis may be seen. (The degree of abnormality is proportionate to the duration of symptoms prior to presentation).
    • If diagnosis is not established clinically, abdominal ultrasound is 95% sensitive in the diagnosis of HPS


    Fluid Management

    • Stop oral feeds
    • Gain IV access
    • Insert a nasogastric tube if profuse vomiting continues despite stopping feeds.

    Purpose Fluid Notes
    Resuscitation 0.9% Sodium Chloride Fluid Resuscitation as required. Not all infants will require fluid resuscitation
    Deficit 0.9% Sodium Chloride + 5% Dextrose + 20mmol KCl

    Refer to dehydration and IV fluids guidelines.

    Note that Plasmalyte is not used in the management of HPS

    Maintenance 0.9% Sodium Chloride + 5% Dextrose + 20mmol KCl
    • Repeat blood gas with electrolytes 6 hourly initially and adjust fluid accordingly.
    • Usually aim to fully correct fluid and electrolyte deficits within 48 hours.
    • Blood bicarbonate levels can be used to monitor response to fluid therapy in HPS. As such, Plasmalyte is not used in the management of HPS as it contains bicarbonate precursors that may affect this process.
    • Surgical Correction of HPS is usually delayed until correction of acid/base status, electrolyte disturbances and dehydration.
    • It is particularly important to fully correct serum bicarbonate before surgery because of the risk of hypoventilation/apnoea post-operatively in the setting of a metabolic alkalosis.

     Consider consultation with local paediatric team when:

    • all children with pyloric stenosis should be managed as an inpatient
    • consult with a paediatric surgeon
    • transfer to a tertiary paediatric centre if feasible​

    Consider transfer when:
    Transfer to a paediatric centre early once an initial management plan is in place.

     Discharge requirements:

    • tolerating full oral feeds
    • pain free
    • surgical clearance

    Parent information sheet.

    For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

    Information Specific to RCH – Including who to consult for inpatients.

    Specimen collection and results

    Pyloric Stenosis flowchart 

    Pyloric Stenosis flowchart

    Last revised December, 2016