Fact-sheet: Hypertrophic pyloric stenosis
Updated on 09/27/2019 at 10:17 AM
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Definition
It is defined as a progressive thickening of the pyloric muscle fibers.
This hypertrophy involves a well-delineated anatomic zone extending from the terminal portion of the gastric antrum to the duodenum.
This obstruction produces a typical clinical picture, the first signs of which are non-bilious, projectile vomiting of curdled milk
Its diagnosis is suggested by clinical findings
Diagnostic confirmation is obtained by ultrasound.
It affects 2 to 3 per 1000 newborns, aged 1 month (3 weeks - 3 months).
A symptom-free interval after birth is almost always present
On average, there are 3.7 affected boys for every affected girl
Clinical features
Non-bilious, MILKY projectile vomiting
Epigastric fullness
Peristaltic waves
Non-distended abdomen
Palpable pyloric olive
Signs of dehydration, malnutrition
Hungry newborn or infant
Radiography
Upper GI series:
Only in cases of diagnostic uncertainty or atypical forms (pyloric dysgenesis)
- Imprint of the pyloric olive on the gastric antrum with a string-like appearance of the antropyloric region
- Defrenne sign: upward curvature of the pyloric channel
Indicated if symptoms persist postoperatively
Ultrasound
Ultrasound = reference examination:
- Pyloric wall thickness > 3 mm
- Overall pyloric diameter > 12 mm
- Pyloric length > 15 mm
At the outset, if thickening is borderline, follow-up at 24-48h.
Pyloric olive:
- Thick, hypoechoic ring (hypertrophied muscle) around a hyperechoic center (mucosa)
- The curved appearance of the pylorus is a useful diagnostic feature
- Position just medial to, or even in contact with, the gallbladder
Dynamic signs:
- Prominent antral peristalsis
- Absence of fluid and air passage through the canal
- Stomach stasis (examination in supine or right lateral decubitus position)
- Shoulder sign
CT
Not indicated
MRI
Not indicated
Management
The treatment of choice is extramucosal pyloromyotomy, first described in France in 1907.
It is known as the Fredet-Ramstedt procedure.
Recent innovations have focused on improving cosmetic outcomes.
Correction of fluid and electrolyte disturbances is essential before anesthesia and surgery.
Differential diagnosis
- Pyloric spasm
- Duodenal obstruction or midgut volvulus: greenish, bilious vomiting
- Pyloric lipid infiltration: in the setting of familial hyperlipidemia, marked, hyperechoic, and hyperemic pyloric hypertrophy
- Foveolar hyperplasia
- In older children: sarcoidosis, granulomatosis