What causes pyloric stenosis (narrowing of the pylorus)?

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Last updated: March 2, 2025 • View editorial policy

From the Research

Pyloric stenosis is primarily caused by peptic ulcer disease, particularly chronic duodenal ulcers that lead to inflammation, scarring, and narrowing of the pyloric channel, as supported by the most recent study 1. The pathophysiology of pyloric stenosis involves inflammation leading to fibrosis and scarring, which narrows the pyloric opening between the stomach and duodenum, preventing normal gastric emptying and resulting in symptoms like persistent vomiting, early satiety, upper abdominal pain, and weight loss. Other common causes of pyloric stenosis include:

  • Gastric surgery complications, such as post-pyloroplasty or gastric resection
  • Caustic ingestion, like strong acids or alkalis
  • Chronic NSAID use
  • Malignancies, such as gastric cancer Less frequent causes include:
  • Crohn's disease affecting the gastroduodenal region
  • Radiation therapy to the upper abdomen
  • Congenital pyloric stenosis in infants The diagnosis of pyloric stenosis typically requires upper endoscopy to visualize the stricture and rule out malignancy, as noted in 2. Treatment depends on the underlying cause and may include:
  • Endoscopic balloon dilation, as recommended in 3
  • Surgical intervention, such as pyloroplasty or gastrojejunostomy
  • Addressing the primary condition with medications, such as proton pump inhibitors for peptic ulcer disease, as suggested in 4.

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