Pediatric Hypertrophic Pyloric Stenosis Workup

  • Author: Hisham Nazer, MB, BCh, FRCP, , DTM&H; Chief Editor: Carmen Cuffari, MD  more...
Updated: Sep 23, 2016

Laboratory Studies

Infants with severe vomiting can develop profound hypochloremia and hypokalemia. The classic biochemical abnormality in hypertrophic pyloric stenosis (HPS) is hypochloremic, hypokalemic metabolic alkalosis.


Imaging Studies

Ultrasonography has become the criterion standard imaging technique for diagnosing hypertrophic pyloric stenosis. It is reliable, highly sensitive, highly specific, and easily performed. An experienced ultrasonographer increases the test's predictive value. Necessary measurements include pyloric muscle thickness and pyloric channel length. Muscle wall thickness 3 mm or greater and pyloric channel length 14 mm or greater are considered abnormal in infants younger than 30 days.

Barium upper GI (UGI) study is an effective means of diagnosing HPS when ultrasonography is not diagnostic. It should demonstrate an elongated pylorus with antral indentation from the hypertrophied muscle. The UGI may demonstrate the "double track" sign when thin tracks of barium are compressed between thickened pyloric mucosa or the "shoulder" sign when barium collects in the dilated prepyloric antrum. After UGI barium study, irrigating and removing any residual barium from the stomach is advisable to avoid aspiration.

Although UGI endoscopy would demonstrate pyloric obstruction, physicians would find it difficult to differentiate accurately between hypertrophic pyloric stenosis and pylorospasm. Endoscopy is reserved for patients with atypical clinical signs when ultrasonography and UGI studies are nondiagnostic. Endoscopic dilatation has rarely been used as a method of treatment. This treatment is not standard for hypertrophic pyloric stenosis; endoscopy should be used rarely, if ever.

Contributor Information and Disclosures

Hisham Nazer, MB, BCh, FRCP, , DTM&H Professor of Pediatrics, Consultant in Pediatric Gastroenterology, Hepatology and Clinical Nutrition, University of Jordan Faculty of Medicine, Jordan

Hisham Nazer, MB, BCh, FRCP, , DTM&H is a member of the following medical societies: American Association for Physician Leadership, Royal College of Paediatrics and Child Health, Royal College of Surgeons in Ireland, Royal Society of Tropical Medicine and Hygiene, Royal College of Physicians and Surgeons of the United Kingdom

Disclosure: Nothing to disclose.


Dena Nazer, MD, FAAP Assistant Professor of Pediatrics, Wayne State University School of Medicine; Chief, Child Protection Team, Children's Hospital of Michigan

Dena Nazer, MD, FAAP is a member of the following medical societies: Academic Pediatric Association, American Academy of Pediatrics, American Professional Society on the Abuse of Children, Ray E Helfer Society

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.

B UK Li, MD Professor of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Medical College of Wisconsin; Attending Gastroenterologist, Director, Cyclic Vomiting Program, Children’s Hospital of Wisconsin

B UK Li, MD is a member of the following medical societies: Alpha Omega Alpha, American Gastroenterological Association, North American Society for Pediatric Gastroenterology, Hepatology and Nutrition

Disclosure: Nothing to disclose.

Chief Editor

Carmen Cuffari, MD Associate Professor, Department of Pediatrics, Division of Gastroenterology/Nutrition, Johns Hopkins University School of Medicine

Carmen Cuffari, MD is a member of the following medical societies: American College of Gastroenterology, American Gastroenterological Association, North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, Royal College of Physicians and Surgeons of Canada

Disclosure: Received honoraria from Prometheus Laboratories for speaking and teaching; Received honoraria from Abbott Nutritionals for speaking and teaching. for: Abbott Nutritional, Abbvie, speakers' bureau.

Additional Contributors

Jeffrey J Du Bois, MD Chief of Children's Surgical Services, Division of Pediatric Surgery, Kaiser Permanente, Women and Children's Center, Roseville Medical Center

Jeffrey J Du Bois, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American College of Surgeons, American Pediatric Surgical Association, California Medical Association

Disclosure: Nothing to disclose.


Daniel A Beals, MD Attending Staff, Cornerstone Pediatric Surgery

Daniel A Beals, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Physicians, American Pediatric Surgical Association, American Society for Bioethics and Humanities, Kentucky Medical Association, Society for Fetal Urology, Society of Critical Care Medicine, and Southeastern Surgical Congress

Disclosure: Nothing to disclose.

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