Pyloric stenosisMANAGEMENT

PEDIATRIC-SPECIFIC PRESENTATIONS · 12 SECTIONS

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373 items

☷ Legend

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Cardiovascular Presentations66▾

Respiratory Presentations47▾

Neurological Presentations77▾

Gastrointestinal Presentations63▾

Genitourinary and Reproductive Presentations44▾

Infectious Disease Presentations146▾

Trauma Presentations88▾

Toxicologic Presentations67▾

Psychiatric Presentations25▾

Musculoskeletal and Rheumatologic Presentations89▾

Dermatology Presentations21▾

Environmental and Exposure Presentations26▾

Hematologic and Oncologic Presentations30▾

Pediatric-Specific Presentations13▾

Bronchiolitis Croup Emergency delivery Febrile seizure Intussusception Kawasaki disease Neonatal jaundice Neonatal sepsis Nursemaid's elbow Pediatric fever 0 to 28 days Pediatric fever 29 to 60 days Pediatric fever 61 to 90 days Pyloric stenosis

Endocrine and Metabolic Presentations42▾

ENT and Maxillofacial Presentations21▾

Ophthalmologic Presentations15▾

Obstetric Presentations17▾

Systemic and Miscellaneous Presentations15▾

01Approach to the Critical Patient/attcp35

Key concepts

›Pyloric stenosis overview

›Gastric outlet obstruction from hypertrophy of pyloric circular muscle

›Nonbilious vomiting pattern

›Vomiting after feeds with progressive frequency and force

›Time sensitive priorities

›Volume resuscitation before definitive surgery

›Correct hypochloremic metabolic alkalosis before anesthesia

Immediate stabilization

›Initial priorities

›If apnea cyanosis lethargy shock then resuscitation bay

›Airway positioning suction for active emesis

›If altered mental status then airway protection pathway

›Cardiorespiratory monitoring

›Continuous pulse oximetry

›Continuous ECG for hypokalemia risk

›IV access

›Peripheral IV

›Intraosseous if IV failure in unstable infant

Resuscitation targets

›Physiologic targets

›Perfusion normalization

›Capillary refill improving

›Normal mentation and consolability for age

›Urine output target

›1 mL/kg/hour

›No potassium supplementation until urine output confirmed

›Metabolic targets before OR

›Chloride at least 100 mmol/L

›Bicarbonate 30 mmol/L or less

›Potassium at least 3.5 mmol/L

›Glucose stability during NPO and dextrose infusion

Consultation and escalation

›Team activation

›Pediatric surgery early notification when suspected

›Anesthesia awareness for alkalosis aspiration risk

›Transfer triggers

›No pediatric surgery capability onsite

›Hemodynamic instability despite initial bolus therapy

02History/hx36

Classic presentation

›Symptom pattern

›Nonbilious vomiting

›Progressive volume and force

›Postprandial predominance

›Hunger after vomiting

›Persistent feeding interest

›Short interval repeat feeding attempts

›Weight trajectory

›Poor weight gain

›Weight loss

›Stool and urine changes

›Decreased wet diapers

›Constipation

Risk and timing

›Epidemiologic clues

›Age typical range 2 to 8 weeks

›Earlier or later presentations possible

›Preterm infants may present later corrected age

›Sex association

›Male predominance

›First born association reported in observational cohorts

›Medication and feeding associations

›Macrolide exposure in early life as risk signal

›Formula feeding association reported in observational data

Red flags for alternate diagnosis

›High risk features

›Bilious emesis

›Malrotation with volvulus until proven otherwise

›Emergent surgical pathway

›Hematemesis

›Gastritis milk protein allergy or stress injury

›Coagulopathy consideration if severe

›Fever toxic appearance

›Sepsis meningitis urinary infection

›Broad infectious evaluation

›Lethargy seizures bulging fontanelle

›Intracranial pathology

›Neuroimaging threshold lower

03Physical Exam/exam29

General and hydration

›Vital signs and perfusion

›Tachycardia

›Hypovolemia marker

›Persistent tachycardia after fluids suggests ongoing deficit or sepsis

›Respiratory pattern

›Hypoventilation from metabolic alkalosis compensation

›Apnea risk in young infants

›Hydration

›Sunken fontanelle

›Dry mucous membranes

›Decreased tears

›Delayed capillary refill

Abdominal exam

›Pyloric findings

›Palpable epigastric right upper quadrant olive

›Best after emesis and with relaxed abdominal wall

›Absence does not exclude diagnosis

›Visible gastric peristaltic waves

›Left to right upper abdomen

›More apparent after feeding

›Distension pattern

›Epigastric fullness

›Minimal lower abdominal distension

PITFALLS

›Common misses

›Assuming reflux when vomiting is progressively forceful

›Delayed diagnosis increases dehydration and alkalosis severity

›Early ultrasound in classic age window reduces delays

›Overreliance on olive sign

›Low sensitivity in early disease and in tense infants

›Ultrasound remains diagnostic test of choice

04Differential Diagnosis/ddx33

Life threatening

›Surgical emergencies

›Malrotation with midgut volvulus

›Bilious emesis

›Abdominal pain distension shock

›Intussusception

›Episodic pain lethargy

›Currant jelly stools later feature

›Incarcerated hernia

›Inconsolable infant

›Groin mass

Medical mimics

›Common pediatric causes

›Gastroesophageal reflux

›Nonprojectile spit ups

›Normal growth

›Viral gastroenteritis

›Diarrhea exposure history

›Fever possible

›Milk protein intolerance

›Blood in stool eczema

›Feeding intolerance

›Urinary tract infection

›Fever irritability

›Vomiting without diarrhea

Less common

›Metabolic and neurologic

›Congenital adrenal hyperplasia salt wasting

›Dehydration

›Hyperkalemia hyponatremia

›Increased intracranial pressure

›Bulging fontanelle

›Poor feeding lethargy

›Inborn errors of metabolism

›Poor feeding lethargy

›Metabolic acidosis patterns more typical than alkalosis

05Laboratory Tests/lt29

Electrolytes and acid base

›Core chemistry panel

›Sodium chloride potassium bicarbonate

›Hypochloremic metabolic alkalosis pattern

›Severity correlates with duration of vomiting

›Glucose

›Hypoglycemia risk in prolonged poor intake

›Dextrose infusion planning

›Urea creatinine

›Prerenal azotemia signal

›Fluid deficit estimation

Blood gas

›Venous blood gas

›pH and bicarbonate confirmation

›Alkalemia magnitude for anesthesia planning

›CO2 retention compensation pattern

Additional tests when indicated

›Infection evaluation triggers

›Urinalysis and urine culture for fever or no clear surgical diagnosis

›Neonatal sepsis risk considerations

›Blood culture for ill appearance

›Hematology triggers

›Complete blood count for toxic appearance or dehydration severity

›Hemoconcentration

›Leukocytosis nonspecific stress response

Pitfalls and interpretation

›Lab interpretation cautions

›Normal electrolytes possible early

›Ultrasound indicated by clinical picture despite normal labs

›Do not delay imaging for labs in stable infant

›Potassium may appear normal or high with hemolysis

›Repeat confirm before aggressive replacement

›Continuous ECG monitoring when replacing

06Diagnostic Tests/dt38

Scoring Systems

›Decision tools

›No validated clinical score replaces ultrasound diagnosis

›Clinical probability based on age pattern vomiting and alkalosis

›Bilious emesis shifts pathway to malrotation evaluation

MRI

›MRI role

›Rare use

›Alternative when ultrasound nondiagnostic and CT avoided

›Limited by availability and sedation considerations

›MRI findings

›Pyloric muscle hypertrophy visualization

›Gastric outlet obstruction appearance

›CT role

›Generally avoided in infants

›Radiation exposure concern

›Consider only when alternative diagnosis requires CT and ultrasound unavailable or nondiagnostic

›CT findings

›Thickened pylorus

›Gastric distension

Ultrasound

›Ultrasound first line

›Diagnostic performance high in experienced hands

›Direct measurement of pyloric muscle

›Real time observation of gastric emptying failure

›Standard criteria

›Muscle thickness threshold commonly 3 mm or greater

›Pyloric channel length threshold commonly 15 mm or greater

›Functional criteria

›Failure of gastric contents passage

›Persistent pyloric opening failure during observation

›Technique pearls

›Right lateral decubitus positioning

›Small oral glucose water to distend stomach if needed

›Repeat ultrasound after hydration if borderline measurements

›Early disease can have evolving measurements

›Pitfalls

›Pylorospasm mimicker

›Transient opening and passage argues against stenosis

›Dehydration can reduce measurements

›Reassess after resuscitation if equivocal

07Disposition/dispo20

Level of care

›Admission expectations

›Hospital admission typical for all confirmed cases

›NPO and IV fluids

›Surgical planning after metabolic correction

›ICU considerations

›Apnea or severe alkalemia with hypoventilation

›Hemodynamic instability

›Significant electrolyte derangements requiring frequent monitoring

›Refractory hypochloremia or hypokalemia

Transfer

›Interfacility transfer criteria

›No pediatric surgery availability

›Transfer after stabilization and NG decompression if needed

›Ongoing IV chloride repletion during transport

›Diagnostic uncertainty with bilious emesis

›Transfer for emergent upper GI contrast study or pediatric surgery evaluation

›Do not delay for outpatient imaging

Discharge rare scenarios

›Discharge avoidance

›Suspected pyloric stenosis without completed imaging

›Return within hours for ultrasound if immediate imaging unavailable

›Safety net instructions and hydration plan

08Treatment/t63

Initial ED management

›NPO and aspiration reduction

›NPO status

›Strict no oral feeds until surgical plan clarified

›Dextrose containing IV fluids to prevent hypoglycemia

›Gastric decompression indications

›Persistent vomiting

›Significant distension

›Nasogastric tube low intermittent suction

›Large volume removal can improve ventilation and comfort

Fluid resuscitation

›Isotonic bolus strategy

›0.9% sodium chloride 20 mL/kg IV

›Repeat bolus for ongoing hypoperfusion

›Reassess perfusion after each bolus

›Dextrose bolus only if symptomatic hypoglycemia

›Dextrose 10% 2 mL/kg IV

›Recheck glucose in 15 minutes

Maintenance and deficit replacement

›Ongoing IV fluids

›0.9% sodium chloride with dextrose 5% infusion

›Rate based on weight maintenance plus deficit correction plan

›Avoid hypotonic solutions during active resuscitation

›Potassium supplementation rules

›Add potassium chloride only after urine output established

›Typical starting concentration 20 mmol KCl per liter

›Potassium repletion targets

›Potassium at least 3.5 mmol/L before anesthesia

›Continuous ECG monitoring during significant replacement

Electrolyte correction goals

›Preoperative metabolic correction

›Chloride repletion primary driver

›Chloride at least 100 mmol/L goal

›0.9% sodium chloride preferred chloride source

›Alkalosis correction

›Bicarbonate 30 mmol/L or less goal

›Ventilation strategy adjustments in severe alkalemia

›Sodium correction

›Avoid rapid sodium shifts

›Frequent electrolytes in severe dehydration

Definitive therapy

›Surgical pyloromyotomy

›Standard definitive treatment

›Timing after resuscitation and metabolic normalization

›Not a true surgical emergency when stabilized

›Antibiotic prophylaxis per local protocol

›Cefazolin single perioperative dose commonly used

›Alternative for severe beta lactam allergy per protocol

Nonoperative option

›Atropine therapy pathway

›Consider only with pediatric surgery guidance

›Poor surgical candidate or resource limited setting

›Slower symptom resolution than pyloromyotomy

›Atropine regimen varies by institution

›IV atropine initiation with transition to oral dosing in some protocols

›Continuous monitoring for anticholinergic adverse effects

›Treatment success monitoring

›Tolerance of feeds

›Ultrasound improvement trend

Postoperative care essentials

›Feeding after pyloromyotomy

›Early feeding protocols common

›Small frequent feeds advancement as tolerated

›Postop emesis possible and usually self limited

›Analgesia

›Acetaminophen weight based dosing

›Opioid sparing approach preferred

›Complication surveillance

›Persistent vomiting beyond expected window

›Incomplete pyloromyotomy consideration

09Special Populations/sp20

Pregnancy

›Pregnancy relevance

›Not applicable in typical disease population

›Pregnancy testing not routine in infant evaluation

›Maternal pregnancy status not a driver of infant management

Geriatric

›Geriatric relevance

›Not applicable

›If adult gastric outlet obstruction then alternate differential pathway

›Malignancy peptic ulcer disease pancreatitis considerations

Pediatrics

›Pediatric specific considerations

›Weight based dosing required for all medications and fluids

›Use kilograms only

›Double check concentration and units mmol/L for electrolytes

›Neonates young infants risk

›Hypoglycemia vulnerability with prolonged NPO

›Dextrose containing maintenance fluids

›Apnea risk with alkalosis and sedation

›Higher level monitoring when severe alkalemia

›Child protection and feeding history

›Feeding technique assessment

›Supportive counseling after diagnosis confirmed

10Background/b36

Epidemiology

›Population patterns

›Most common surgical cause of nonbilious vomiting in early infancy

›Typical onset weeks after birth

›Rare after 3 months of age

›Sex distribution

›Male predominance

›Familial clustering reported in observational studies

›Risk associations

›Early macrolide exposure association signal

›Multifactorial etiology with genetic and environmental factors

Pathophysiology

›Mechanism

›Hypertrophy and hyperplasia of pyloric smooth muscle

›Narrowed pyloric canal

›Impaired gastric emptying

›Metabolic consequences

›Loss of gastric hydrochloric acid

›Hypochloremic metabolic alkalosis

›Secondary renal handling

›Potassium wasting during volume depletion

›Paradoxical aciduria concept in severe cases

›Renal bicarbonate conservation shifts with chloride depletion

Therapeutic Considerations

›Treatment rationale

›Preoperative correction reduces anesthesia risk

›Alkalosis increases apnea risk

›Hypochloremia impairs ventilatory drive compensation

›Fluid selection rationale

›Chloride repletion key for alkalosis correction

›Isotonic saline preferred during correction phase

›Definitive therapy rationale

›Pyloromyotomy provides rapid durable relief

›Atropine slower and requires prolonged monitoring

›Evidence grading notes for this tool

›Many recommendations derived from pediatric surgery and radiology consensus

›Evidence mapping listed as ACEP Level C equivalent when high quality emergency medicine grading not available

›Surgical pyloromyotomy considered Class I consensus standard of care

›Preoperative metabolic correction considered Class I consensus standard

11Patient Discharge Instructions/pdi20

Copy discharge instructions

›Post pyloromyotomy discharge set

›Feeding plan per surgery team

›Small frequent feeds

›Gradual increase in volume as tolerated

›Expected symptoms

›Mild spit ups or occasional vomiting for 24 to 48 hours

›Improving trend expected

›Wound care

›Keep incision clean and dry per instructions

›Bathing restrictions per surgery team

›Return to ED immediately

›Green bilious vomiting

›Repeated vomiting with poor intake or fewer wet diapers

›Fever or worsening lethargy

›Breathing pauses or color change

›Redness swelling drainage at incision

›Persistent abdominal distension

›Follow up

›Pediatric surgery follow up appointment

›Primary care weight check within 1 to 2 weeks

12References/r14

Clinical guidelines and society statements

›Reference list

›Pediatric surgery standard texts and institutional pathways for hypertrophic pyloric stenosis

›Emphasis on preoperative correction of hypochloremic alkalosis before pyloromyotomy

›Postoperative feeding advancement protocols vary by institution

›Radiology practice references for ultrasound diagnostic criteria

›Muscle thickness and channel length thresholds with functional assessment

›Repeat ultrasound strategy for equivocal early disease

›Evidence grading statement for this tool

›ACEP Level A B C labels used as internal evidence mapping

›Class I IIa IIb labels used as internal recommendation strength mapping

Evidence based sources

›Evidence anchors

›Observational epidemiology studies on risk factors including sex distribution and macrolide association

›Meta analyses and cohort studies informing ultrasound criteria and atropine outcomes

›Perioperative anesthesia safety literature on alkalosis and apnea risk

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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