Purpose. To analyze changes in the clinical condition at presentation
and methods of establishing the diagnosis of infantile hypertrophic py
loric stenosis (IHPS). Methods. Retrospective review of patients who u
nderwent pyloromyotomy (PM) for suspected IHPS at two institutions fro
m 1969 through 1994 was performed. For the purposes of comparison, the
population was divided into five equal time periods. Results. Over th
e 25-year period, 901 infants underwent PM. Patients presented at a yo
unger age, weighed more, and had a shorter length of illness in the mo
st recent time period. Hypochloremic alkalosis was found half as frequ
ently in the most recent time period compared to the earliest group. A
palpable pyloric tumor was present in 79% of patients in the earliest
time period compared with 23% in the mast recent time period. Sixty-o
ne percent of patients in the earliest group and 96% in the latest gro
up underwent an imaging study, reflecting the referring physician's ev
aluation before referral to the surgeon. Conclusions. Currently, patie
nts with IHPS less frequently present with the clinical hallmarks of t
he disease. The use of imaging studies to establish the diagnosis has
become common practice. The result has been the diagnosis of IHPS befo
re alkalosis has developed, a shorter clinical course, less morbidity,
and a shorter postoperative hospital stay.