Ultrasonographic evaluation of pyloric hypertrophy

1. ULTRASOUND IN INFANTILE
HYPERTROPHIC PYLORIC
STENOSIS
Hospital Militar de Zona Cuernavaca. Morelos
drromelflores@hotmail.com

2. Hypertrophic pyloric
• Infantile
hypertrophic pyloric
stenosis (IHPS) is a
disorder of young
infants caused by
hypertrophy of the
pylorus, which can
progress to near-
complete
obstruction of the
gastric outlet,
leading to forceful
vomiting.

3. EPIDEMIOLOGY
• Infantile hypertrophic
pyloric stenosis (IHPS)
occurs in approximately 2
to 3.5 per 1000 live births
• It is more common in
males than females
• In infants born preterm.
• Approximately 30 to 40
percent of cases occur in
first-born children It is less
common in infants of older
mothers
• Symptoms usually begin
between 3 and 5 weeks of
age
• Is very rarely occur after
12 weeks of age

4. The etiology of IHPS
• Is unclear but probably
is multifactorial,
involving genetic
predisposition and
environmental factors.
• Neonatal
hypergastrinemia and
gastric hyperacidity
may play a role.
• Prematurity (<37
weeks gestation) may
be a risk factor.

5. Environmental factors
• Maternal
smoking during
pregnancy
increases the risk
for IHPS
• Bottle feeding
rather than
breastfeeding
increases the risk
for IHPS

6. Risk factors
• maternal
history of
pyloric
stenosis

7. Associations
• Turner syndrome
• tracheo-
oesophageal
fistula
• oesophageal
atresia
• trisomy 18

8. Pathology
• HPS is the
result of both
hyperplasia and
hypertrophy of
the pyloric
circular muscles
fibres.
The pathogenesis of this is not
understood. There are four main
theories
immunohistochemical abnormalities
genetic abnormalities
infectious cause
hyperacidity theory

9. Clinical presentation
• Is typical with non-
bilious projectile
vomiting.
• The hypertrophied
pylorus can be palpated
as an olive-sized mass
in the right upper
quadrant.
• A succussion splash
may be audible, and
although common, is
only relevant if heard
hours after the last
meal

10. Clinical presentation
•Jaundice. The infant may
develop jaundice, which is
corrected upon correction of the
disease.
•Dehydration and
malnutrition. As the obstruction
becomes more severe, the
infant begins to
show signs of dehydration and
malnutrition, such as poor
weight gain, weight loss,
marasmus,
decreased urinary output,
lethargy, and shock.

11. Radiographic features
• Plain
radiograph
• Abdominal x-
ray findings are
non-specific but
may show a
distended
stomach with
minimal distal
intestinal bowel
gas.

12. Ultrasound
• Ultrasound is the
modality of choice
in the right clinical
setting because of
its advantages
over a barium meal
are that it directly
visualises the
pyloric muscle and
does not use
ionising radiation.

13. Ultrasound
• THE DIAGNOSTIC
PRECISION APPROXIMATES
100%
• AT THE CURRENT
MOMENT, ECOGRAPHY IS
THE METHOD OF CHOICE.
• IT IS EASY
• QUICK
• NOT INVASIVE
• NO IONIZING
MUSCLE
Normal pylorus
Hipertophied pylorus
MUSCLE
Mucosa
mucosa
Muscle

14. Easy ultrasound technique
• Is to find gallbladder
then turn the probe
obliquely sagittal to
the body in an
attempt to find
pylorus
longitudinally

15. NORMAL ANATOMY

16. TECHNIQUE
WITH THE STOMACH
FULL OF CLEAR LIQUID
LOCALIZE THE END OF
THE GASTRIC ANTRO AND
THE FIRST PORTION OF
THE DUODENUM, THE
NORMAL TRANSIT WILL
ESTABLISH THE
DIFFERENCE.

17. TECHNIQUE
IT IS APPRECIATED IN
LONGITUDINAL AND
TRANSVERSAL CORTES
LOCATING MEDIAL TO
THE BILIARY, PREVIOUS
AND FLOWED VESICULA
TO THE VEIN PRIOR TO
THE RHINE AND SIDE TO
THE HEAD OF THE
PANCREAS

18. In a normal situation, the
thickness of the pyloric
muscle (diameter of a
single muscular wall in a
transverse image)
Measurements
Should normally be less than 3 mm (more accuratemm 3) and the length
(longitudinal measurement) should not exceed 15

19. Cross-section

20. LONGITUDINAL

21. ULTRASOND

22. Diagnosis
Straightforward if olive is present
Difficult to distinguish from GERD
esp in early stages
US has become the standard at
most centers
Ultrasound – Sensitivity of 90%
Criteria for diagnosis – pyloric
muscle thickness greater than 4
mm and an overall pyloric muscle
length greater than 14mm

23. • At the moment, ultrasound
is the method of choice for
the diagnosis of pyloric
hypertrophy

24. •Thank you