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Pediatric Pyloric Stenosis Workup

  • Author: Jagvir Singh, MD; Chief Editor: Kirsten A Bechtel, MD  more...
Updated: Jul 27, 2015

Laboratory Studies

See the list below:

  • Electrolytes, pH, BUN, and creatinine levels should be obtained at the same time as intravenous access in patients with pyloric stenosis.
    • Hypochloremic, hypokalemic metabolic alkalosis is the classic electrolyte and acid-base imbalance of pyloric stenosis. Persistent emesis causes progressive loss of fluids rich in hydrochloric acid, which causes the kidneys to retain hydrogen ions in favor of potassium. Electrolyte abnormalities depend on the duration of symptoms in the affected infant.
    • The dehydration may result in hypernatremia or hyponatremia and may result in prerenal renal failure.
  • Elevated unconjugated bilirubin levels may be present.

Imaging Studies

See the list below:

  • If the clinical presentation is typical and an olive is felt, the diagnosis is confirmed and further imaging is not warranted.
  • Ultrasonography is the imaging modality of choice when evaluating a child for infantile hypertrophic pyloric stenosis (IHPS).[11] It is both highly sensitive (90-99%) and specific (97-100%) in the hands of a qualified sonographer. The pylorus is viewed in longitudinal and transverse planes. The sonographic hallmark of infantile hypertrophic pyloric stenosis is the thickened pyloric muscle.
  • Criteria for making the diagnosis include pyloric muscle thickness greater than 4 mm. The length of the pyloric canal is variable and may range from 14 mm to 20 mm. The pyloric diameter may range from 10-14 mm.
    • Infantile hypertrophic pyloric stenosis may be falsely diagnosed in infants who have pylorospasm. Ultrasonography also allows for observation of peristaltic activity, differentiating between pylorospasm and true infantile hypertrophic pyloric stenosis.
    • Upper GI imaging (UGI) can help to confirm the diagnosis of infantile hypertrophic pyloric stenosis but is not routinely performed unless ultrasonography is nondiagnostic.
  • The "shoulder" sign is a collection of barium in the dilated prepyloric antrum and may be seen in the infant with infantile hypertrophic pyloric stenosis. The "double track" sign (ie, 2 thin tracks of barium compressed between thickened pyloric mucosa), once thought to be pathognomonic of infantile hypertrophic pyloric stenosis, has recently been identified in multiple cases of sonographically confirmed pylorospasm and is shown in the image below.
    Lateral view from an upper GI study demonstrates tLateral view from an upper GI study demonstrates the double-track sign.


See the list below:

  • Upper GI endoscopy has been used as an adjunct diagnostic tool in select cases of infantile hypertrophic pyloric stenosis when other imaging tests are inconclusive or when the infant presents with atypical clinical features.
Contributor Information and Disclosures

Jagvir Singh, MD Director, Division of Pediatric Emergency Medicine, Lutheran General Hospital of Park Ridge

Jagvir Singh, MD is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Nothing to disclose.


Richard H Sinert, DO Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Vice-Chair in Charge of Research, Department of Emergency Medicine, Kings County Hospital Center

Richard H Sinert, DO is a member of the following medical societies: American College of Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Grace M Young, MD Associate Professor, Department of Pediatrics, University of Maryland Medical Center

Grace M Young, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Emergency Physicians

Disclosure: Nothing to disclose.

Chief Editor

Kirsten A Bechtel, MD Associate Professor of Pediatrics, Section of Pediatric Emergency Medicine, Yale University School of Medicine; Co-Director, Injury Free Coalition for Kids, Yale-New Haven Children's Hospital

Kirsten A Bechtel, MD is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Nothing to disclose.

Additional Contributors

Garry Wilkes, MBBS, FACEM Director of Clinical Training (Simulation), Fiona Stanley Hospital; Clinical Associate Professor, University of Western Australia; Adjunct Associate Professor, Edith Cowan University, Western Australia

Disclosure: Nothing to disclose.


Dara A Kass, MD Clinical Assistant Instructor, Department of Emergency Medicine, State University of New York Downstate Medical Center, Kings County Hospital

Dara A Kass, MD is a member of the following medical societies: American College of Emergency Physicians, Emergency Medicine Residents Association, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

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Lateral view from an upper GI study demonstrates the double-track sign.
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