Pyloric Stenosis

Description

Acquired narrowing of the pyloric canal due to progressive hypertrophy of pyloric muscle leading to obstruction

Epidemiology

• Presentation is most common between 2 and 8 weeks of age, with a median presentation of 6 weeks
• The most common condition requiring surgical intervention in the 1st year of life

Incidence

• Highest incidence found in first-born males
• Overall 1.56 per 1,000 live births
• Higher in Caucasian and Hispanic children

Etiology and Pathophysiology

• Impaired physiologic relaxation of the pyloric muscle leads to hypertrophy.
• Gastric outflow is obstructed, leading to gastric distension and forceful projectile postprandial vomiting.

Risk Factors

• Maternal smoking during pregnancy
• C-section delivery
• Prematurity
• Formula feeding which may cause higher serum levels associated with pylorospasm
• Postnatal macrolide antibiotics, especially if administered in the first 2 weeks of life
• Multiple gestations:
  • 200-fold increased risk if monozygotic twin affected
  • 20-fold increased risk if dizygotic twin affected

General Prevention

Breast milk contains increased vasoactive intestinal peptides which are agents of smooth muscle relaxation.

Commonly Associated Conditions

Hiatal and inguinal hernias