Pyloric stenosis

Case contributed by Dr Clarissa Valle


Vomiting after feeding. Ultrasound examination was requested in suspicion of pyloric stenosis.

Patient Data

Age: 1 month
Gender: Male

The ultrasound examination showed a hypertrophic pylorus. 

  • Length: 22 mm (n.v. <15 mm)
  • Single muscle thickness: 3.7 mm (n.v. <3 mm)
  • Pyloric width: 11.7 mm (n.v. <7 mm)

Case Discussion

The patient underwent an extramucosal longitudinal myotomy of the pylorus known as Fredet-Ramstedt procedure, where the pyloric hypertrophy was confirmed.

Hypertrophic pyloric stenosis affects 2 to 5 every 1,000 births with a prevalence in first-born male patients and a peak presentation during the 4th week of life. The definitive surgical treatment is the pyloromyotomy. 

Patients are usually referred on an emergent basis. Clinical presentation includes nonbilious vomiting, being often mistaken for onset of gastroesophageal reflux. The possible subsequent gastric obstruction leads to vomiting after every feeding. 

Diagnosis relies on ultrasonography as the first-line option, with a sensitivity and specificity approaching 100% in experienced hands.

Pyloric US should be performed using a high-resolution linear-array transducer, positioned in a transverse oblique plane parallel to the right lower costal margin. 

Liquid passes readily from the gastric antrum into the duodenal bulb when the pylorus is normal. If the stomach is empty, liquid can be given orally in order to improve pyloric visualization. 
Persistent thickening of the pyloric muscle is the most important finding. Standard measurements are performed on the long-axis views (see images attached with normal values reported). 

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.