Congenital Pyloric Stenosis

Ashwin Kumar

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

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

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

Etiology

Cause is unknown, but abnormal muscle innervation, breast feeding and maternal stress in the 3rd trimester have been implicated

Elevated serum PG’s, reduced levels of pyloric nitric oxide synthase and infant hypergastrinemia have been found

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 1st week and as late as the 5th month

Clinical Manifestations

After vomiting, infant is hungry and wants to feed againProgressive loss of fluid, hydrogen ion and chloride leads to a hypochloremic metabolic alkalosis.Serum K levels are maintainedGreater awareness has led to earlier diagnosis

Clinical Manifestations

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

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

Diagnosis

Straightforward if olive is presentDifficult to distinguish from GERD esp in early stagesUGI or US can be used – but US has become the standard at most centersUltrasound – Sensitivity of 90%Criteria for diagnosis – pyloric muscle thickness greater than 4 mm and an overall pyloric muscle length greater than 14mm

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

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

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.

Differential

Vomiting with diarrhea suggests gastroenteritis.

Always have to think of increased ICP, subdural hematoma

Systemic infections can also cause persistent vomiting.

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

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

Treatment

Persistent vomiting suggests an incomplete pyloromyotomy, gastritis, GERD.

Surgical treatment is curative with a low mortality rate