Hypertrophic Pyloric Stenosis in a Four-Week-Old Infant - Radiological Diagnosis and Pitfalls

Sep 30, 2026

Infantile hypertrophic pyloric stenosis (IHPS) is a common cause of acquired obstruction in early infancy, driven by pyloric muscle hypertrophy that can produce complete or near-complete gastric outlet obstruction. Typical symptoms include projectile, non-bilious vomiting, and classic bedside findings may be present. Ultrasonography is the diagnostic method of choice, using validated measurements of muscle thickness and canal length, while avoiding pitfalls created by conditions such as pylorospasm or prostaglandin-related changes.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Abstract

Introduction

Case Presentation

Radiological Findings

Abdominal Radiograph

Ultrasonography

Review began 11/17/2025 Review ended 12/04/2025 Published 12/06/2025 © Copyright 2025 Pokhrel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. DOI: 10.7759/cureus.98606 Open Access Case Report Hypertrophic Pyloric Stenosis in a Four-Week-Old Infant: Radiological Diagnosis and Pitfalls Biraj Pokhrel 1, 2, Aaraju Bhatta 3, Anil Basnet 4, Niraaz Pokhrel 5, Dosti Regmi 6 1. Department of General Medicine, Prithvi Chandra Hospital, Ramgram, NPL 2. Department of Medicine, Tribhuvan University Institute of Medicine, Kathmandu, NPL 3. Department of Internal Medicine, Patan Academy of Health Sciences, Lalitpur, NPL 4. Department of Medicine, Shahid Gangalal National Heart Centre, Kathmandu, NPL 5. Department of Radiology, Nepalese Army Institute of Health Sciences, Kathmandu, NPL 6. Department of Pediatric Radiology, Le Bonheur Children 's Hospital, Memphis, USA Corresponding author: Biraj Pokhrel, [pokhrelbiraaz1997@gmail.com](pokhrelbiraaz1997@gmail.com) Abstract Infantile hypertrophic pyloric stenosis (IHPS) is a common acquired condition of infancy, characterized by pyloric muscle hypertrophy leading to complete or near-complete gastric outlet obstruction. A typical presentation includes projectile, non-bilious vomiting. While the palpable "olive " and visible peristaltic waves are classic signs, ultrasonography is the diagnostic modality of choice due to its high accuracy. Diagnosis relies on established sonographic thresholds for pyloric muscle thickness and canal length. Differential diagnoses include transient pylorospasm, which resolves on its own, and prostaglandininduced mucosal hypertrophy, where only the muscular wall should be measured. Herein, we present the case of a four-week-old male infant with projectile non-bilious vomiting and failure to thrive. Ultrasonography confirmed the diagnosis, demonstrating the classic radiological signs. The patient was successfully managed with fluid resuscitation and a Ramstedt pyloromyotomy. This case highlights the pivotal role of ultrasonography in diagnosing IHPS, discusses relevant differential diagnoses, and underscores the importance of recognizing potential imaging pitfalls, such as a posteriorly displaced pylorus due to an overdistended stomach. Categories: Radiology, Pediatric Surgery, Pediatrics Keywords: gastric outlet obstruction, hypertrophic pyloric stenosis, infant, pyloromyotomy, ultrasonography Introduction Infantile hypertrophic pyloric stenosis (IHPS) is a condition affecting young infants, usually in the second to 12th weeks of life, characterized by abnormal thickening of the pyloric musculature in the stomach [1,2] . This hypertrophy leads to a progressive, near-complete gastric outlet obstruction. While the precise etiology remains elusive, IHPS is understood to have a multifactorial origin, incorporating genetic predispositions, hormonal influences, neurogenic factors, and environmental triggers such as maternal macrolide exposure (e.g., erythromycin), smoking, and bottle feeding [3-5]. This condition demonstrates a strong male predominance, with a reported male-to-female ratio of approximately 5 : 1 [2] . Timely diagnosis is paramount to facilitate prompt intervention and prevent complications such as dehydration and electrolyte imbalances. In this context, ultrasonography has emerged as the diagnostic modality of choice. The literature robustly supports the diagnostic accuracy of key sonographic measurements, including pyloric muscle thickness, channel length, and pyloric diameter, for confirming IHPS [6] . While an abdominal radiograph may occasionally reveal a "caterpillar sign," this finding is not consistently present, limiting its reliability [7] . Herein, we present a case of IHPS, with a primary focus

FAQs

What clinical presentation suggests infantile hypertrophic pyloric stenosis (IHPS)?

IHPS commonly presents with projectile, non-bilious vomiting after feeds and may include decreased weight gain due to failure to thrive.

Why is ultrasonography preferred for diagnosing IHPS?

Ultrasonography provides high diagnostic accuracy and relies on established sonographic thresholds for pyloric muscle thickness and canal length.

What radiological pitfalls can affect interpretation of IHPS imaging?

Potential pitfalls include measuring the wrong structure when mucosal hypertrophy is present and misinterpreting apparent pyloric displacement, such as when the stomach is overdistended causing posterior displacement of the pylorus.

Sep 30, 2026

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