Infantile hypertrophic pyloric stenosis

Case contributed by Claire Isidro


5 week old boy with projectile emesis directly after feeds.

Patient Data

Age: 5 weeks
Gender: Male

Ultrasound was completed at the time of baby's feed with the baby in supine position. The pylorus is visualized in longitudinal and transverse views. In the longitudinal view, pyloric stenosis is suspected by visualization of the cervix sign. This sign is meant to express a thickened and hypertrophied pyloric muscle. The measured thickness was found to be >4mm. In the transverse view, the target or donut sign is recognized. This is meant to represent hypertrophied hypoechoic muscle surrounding echogenic muscle. The thickness was found to be >4mm raising concern for hypertrophy.   

Case Discussion

Infantile hypertrophic pyloric stenosis (IHPS) is intimately related to the evolution of ultrasound. Before US, upper GI studies were the exam of choice. US was then found to reliably measure pyloric muscle thickness and length and soon became the modality of choice for diagnosis of IHPS. 

IHPS is found more in male infants. The incidence is about 2-5 per one thousand births per year. It typically occurs between five weeks to eight weeks of life. The baby presents with extreme hunger. Emesis often occurs immediately after feeding. 

The exact pathogenesis is not known but is attributed to the failure of the pyloric muscle to relax, muscular hypertrophy, and obstruction. To diagnose IHPS, an ultrasound should be completed at the time of a baby's feed. Bottle feedings are preferred to control flow. An initial view of the stomach, gastroesophageal junction, and pylorus should be obtained. Additional images of the pylorus in different views should be obtained periodically after the start of the feed.

Multiple references provide measurement criteria to confirm IHPS. IHPS is typically suspected if wall thickness is from 3-5mm in diameter and pyloric channel length is between 15-17 mm. Common findings include the cervix sign and target sign as discussed above. Treatment for IHPS is a pyloromyotomy 

This case was submitted with supervision and input from:

Soni C Chawla, M.D.
Associate Professor
Department of Radiological Sciences
David Geffen School of Medicine at UCLA
Olive View - UCLA Medical Center

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