The ultrasound image shows a classic longitudinal view of a markedly thickened pyloric muscle with an elongated pyloric channel. This finding is consistent with hypertrophic pyloric stenosis (HPS), a condition most commonly seen in male infants between 2 and 8 weeks of age.
The most characteristic clinical finding associated with HPS is an "olive-shaped" palpable mass in the right upper quadrant or epigastric region, which represents the hypertrophied pylorus.
Clinical presentation of HPS includes:
* Non-bilious projectile vomiting (due to gastric outlet obstruction)
* Dehydration and weight loss
* A palpable "olive" mass on physical exam
* Visible peristalsis may be noted on the abdominal wall
Sonographic diagnostic criteria for HPS:
* Pyloric muscle thickness # 3 mm
* Pyloric channel length # 15-17 mm
* "Cervix sign" or "target sign" (transverse view)
* Failure of gastric contents to pass through the pylorus on real-time imaging Differentiation from other options:
* B. Fever of unknown origin: Not characteristic of HPS.
* C. Red currant jelly stools: Classic for intussusception.
* D. Bilious vomiting: Seen in distal duodenal or jejunal obstruction, not in pyloric stenosis (vomiting is non-bilious in HPS).
References:
Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th Edition. Elsevier, 2018.
Chapter: Gastrointestinal Tract, pp. 474-479.
American College of Radiology (ACR). Appropriateness Criteria - Vomiting in Infants Up to 3 Months of Age.
Radiopaedia.org. Hypertrophic pyloric stenosis:https://radiopaedia.org/articles/hypertrophic-pyloric-stenosis