The extent of muscle hypertrophy in infantile hypertrophic pyloric stenosis does not depend on age and duration of symptoms.

There are conflicting views in the literature about the relationship between the extent of muscle hypertrophy in infantile hypertrophic pyloric stenosis (IHPS) and the age of the patient and duration of symptoms. This study was undertaken to elucidate the exact nature of these relationships. The degree of muscle hypertrophy was assessed by measurement of the DNA concentration in biopsy specimens, a technique that has been used to quantify organ hypertrophy objectively and accurately. Forty-one patients were studied prospectively over 12 months. The results show that the degree of hypertrophy is not age-related, and that all the patients tend to progress to about the same degree of hypertrophy, which then remains constant regardless of the duration of symptoms.