The true cause of pyloric stenosis is hyperacidity.

UNLABELLED: Pyloric stenosis (PS) has no known cause. A testable theory of cause is proposed, based on the inheritance of a parietal cell mass (PCM) at the upper end of the normal range. It is proposed that, until 3-4 wk of age, the obligatory high fasting gastrins are at maximal levels and not able to be diminished by increasing antral acidity. Hence, rising acidity is not reduced by a lowered gastrin during this time, and very high acidity occurs.

CONCLUSION: Persisting duodenal hyperacidity is created by an inherited high PCM and loss of gastrin control. These two factors produce pyloric stenosis through work hypertrophy from repeated pyloric contraction in response to hyperacidity.