ICD-10 Code K31.1 – Adult Hypertrophic Pyloric Stenosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K31.1 – Adult hypertrophic pyloric stenosis
What it is
K31.1 identifies hypertrophic narrowing of the pylorus in an adult, causing gastric outlet obstruction. Use it when documentation states adult hypertrophic pyloric stenosis or a similar confirmed diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include symptoms of gastric outlet obstruction, such as postprandial vomiting, early satiety, and epigastric fullness, with confirmation by imaging, endoscopy, or surgical findings.
When to use this code
Use this code when the provider documents adult hypertrophic pyloric stenosis as the cause of obstruction. It may also apply when the diagnosis is confirmed during evaluation for persistent vomiting or suspected gastric outlet obstruction. Check documentation if the record only says pyloric narrowing.
Do not use for
Do not use K31.1 for infantile hypertrophic pyloric stenosis or for nonspecific vomiting without a documented pyloric diagnosis. If the chart describes another cause of gastric outlet obstruction, code that condition instead.
Coding tip
Verify that the record specifically says adult hypertrophic pyloric stenosis before assigning K31.1.