Paediatrics

Pyloric stenosis

Progressive hypertrophy of the pyloric muscle causes gastric-outlet obstruction in a young infant, producing worsening non-bilious vomiting and dehydration; fluid and electrolyte correction must precede pyloromyotomy.

Definition

Infantile hypertrophic pyloric stenosis is progressive hypertrophy of the pyloric muscle causing gastric-outlet obstruction in a young infant. It presents with forceful non-bilious vomiting and is treated definitively by pyloromyotomy after fluid and electrolyte correction.

First principles

A fixed gastric-outlet obstruction explains the pattern

Hypertrophy and hyperplasia of the pyloric muscle narrow the passage between the stomach and duodenum. The stomach initially compensates with stronger peristalsis, so small vomits can become progressively forceful and projectile. The infant may remain hungry because the obstruction is mechanical and feeds are not reaching the bowel.

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