Clinical Practice Guidelines

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. Surgical management can be delayed until the above are corrected.  


    • Hypertrophic Pyloric Stenosis (HPS) usually presents between 2 and 6 weeks of chronological age with progressive non-bilious vomiting
    • risk factors include: male, first born, 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 in the right upper quadrant at the lateral edge of the rectus abdominis muscle 
      • 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

    Differential diagnoses:

    UTI, Gastro, Reflux, Surgical (e.g. Volvulus, malrotation)



    • 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).
    • abdominal ultrasound can be used to investigate if the diagnosis is not established clinically (95% sensitive in the diagnosis of HPS)
    • urine microscopy and culture to rule out UTI


    • gain IV access
    • stop oral feeds
    • insert a nasogastric tube if profuse vomiting continues despite stopping feeds

    Fluid Management 

    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 potassium

    Refer to dehydration and IV fluids guidelines.

    Note that Plasmalyte is not used in the management of HPS

    Maintenance (ongoing) 0.9% Sodium Chloride + 5% Dextrose + 20mmol potassium
    • surgical correction of HPS is usually delayed until correction of dehydration, acid / base status and electrolyte disturbances 
    • 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

    Monitoring and management:

    • 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. (Therefore Plasmalyte is not used in the management of HPS as it contains bicarbonate precursors that may affect this process)

     Consider consultation with local paediatric team when:

    • all children with pyloric stenosis should be managed as an inpatient
    • consult with a Paediatric Surgeon

    Consider transfer when:

    Transfer to a paediatric centre early once an initial management plan is in place.

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

    Consider discharge when:

    • surgical clearance
    • tolerating full oral feeds
    • pain free

    Parent information sheet

    Pyloric Stenosis

    Last revised March 2019