Pyloric Stenosis

1. Congenital Pyloric Stenosis
Ashwin Kumar

2. Gastric Outlet Obstruction
Hallmark is non-bilious vomiting
Other signs include abdominal distention
and bleeding from secondary inflammation
Most common cause of non-bilious
vomiting is infantile hypertrophic pyloric
stenosis

3. Pyloric Stenosis
First described by Hirschsprung in 1888
Ramstedt described an operative procedure
to alleviate the condition in 1907 – the
procedure used to this day to treat pyloric
stenosis

4. Pyloric Stenosis
3/1000 live births – frequency may be increasing
Most common in whites of Northern European
ancestry, less common in African Americans and
rare in Asians
Four times more common in males – especially
firstborn
Increased in infants with type B or O blood groups
Associated with other congenital defects incl TEF

5. Etiology
Cause is unknown, but abnormal muscle
innervation, breast feeding and maternal
stress in the 3
rd
trimester have been
implicated
Elevated serum PG’s, reduced levels of
pyloric nitric oxide synthase and infant
hypergastrinemia have been found

6. Clinical Manifestations
Non-bilious vomiting is the initial symptom
May or may not be projectile initially
Usually progressive, occurs immediately
after a feeding
Vomiting usually starts after 3 wks of age,
but may develop as early as 1
st
week and as
late as the 5
th
month

7. Clinical Manifestations
After vomiting, infant is hungry and wants
to feed again
Progressive loss of fluid, hydrogen ion and
chloride leads to a hypochloremic metabolic
alkalosis.
Serum K levels are maintained
Greater awareness has led to earlier
diagnosis

8. Clinical Manifestations
Jaundice occurs in 5% of infants with
pyloric stenosis – associated with a
decreased level of glucuronyl transferase

9. Clinical Manifestations
Diagnosis traditionally made by palpation of mass
Firm, movable, approx 2 cm in length, olive
shaped and best palpated from the left
Mass located above and to the right of the
umbilicus in the midepigastrum beneath the liver
edge
Peristaltic wave may be present prior to emesis

10. Diagnosis
Straightforward if olive is present
Difficult to distinguish from GERD esp in early
stages
UGI or US can be used – but 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

11. Diagnosis
US pitfalls – pylorospasm may mimic those of PS,
potential false-pos and false-negative readings
UGI – classic signs are elongated pyloric canal,
the “double tract” sign (parallel streaks of barium
in the narrowed channel, and the “shoulder
sign”(bulge of pyloric muscle into the antrum).
Main pitfall of UGI is radiation exposure

12. Differential
Infants who are reactive to external
stimulation, those fed by inexperienced
caretakers, or those for whom adequate
maternal-infant bonding has not been
established may vomit frequently in the
early weeks of life.
GERD with or without a hiatal hernia may
be confused with PS esp in the early stages

13. Differential
Inborn errors of metabolism may produce
recurrent emesis with alkalosis or acidosis
and lethargy, coma or seizures.
Salt-losing CAH presents with prominent
vomiting shortly after birth. Females will
be virilized, but the genitals appear normal
in males. Acidosis and hyperkalemia
usually present.

14. Differential
Vomiting with diarrhea suggests
gastroenteritis.
Always have to think of increased ICP,
subdural hematoma
Systemic infections can also cause
persistent vomiting.

15. Treatment
Preoperative treatment is directed toward
correcting the fluid/acid-base and
electrolyte imbalances.
Correction of the alkalosis is essential to
prevent postoperative apnea
Surgery is the treatment of choice –
Ramstedt pyloromyotomy

16. Treatment
Ramstedt pyloromyotomy – performed through a
short transverse incision or laparoscopically
Underlying pyloric mass is split without cutting
the mucosa and the incision is closed
Post-op vomiting occurs in ½ the patients and
thought to be due to edema of the pylorus
Feedings can usually be initiated within 12-24
hours

17. Treatment
Persistent vomiting suggests an incomplete
pyloromyotomy, gastritis, GERD.
Surgical treatment is curative with a low
mortality rate