Summary

Background: Hypertrophic pyloric stenosis classically presents as projectile vomiting during the third to fourth week of life associated with good appetite. Additional classical presenting findings include palpation of the pyloric tumor, described as olive-shaped, a visible gastric peristaltic wave after feeding, and hypochloremic, hypokalemic metabolic alkalosis. It was recently claimed that this presentation has changed due to the easier access to gastrointestinal imaging.

Objective: To validate this contention and discuss possible reasons.

Methods: We conducted a retrospective chart review of all patients who underwent pyloromyotomy for HPS[1] between 1990 and 2000. Only patients with confirmed HPS at the time of surgery were included. We also performed a comprehensive review of older studies for comparison.

Results: Seventy patients underwent pyloromyotomy over the 10 year period. Overall, 81% of patients were male infants and the mean age at diagnosis was 40 days. The mean duration of symptoms was 8 days. A firstborn child was noted in 43% of the cases. The classical symptom of projectile vomiting was absent in one-third of the patients, a pyloric tumor was not palpated in one-half of the cases, bicarbonate was higher than 28 mEq/L in 20% and a pH of above 7.45 was present in 25% of patients. Hypochloremia was noted in about one-third. We found a good correlation between ultrasonographic width and length of the pylorus and the intraoperative findings. Pylorus length ≥ 24 mm correlated with significantly longer duration of symptoms. When compared with previous studies, the main findings were not significantly different; namely, mean age at diagnosis, percentage of male gender and duration to diagnosis. The decrease in the number of pyloric tumors palpated paralleled the increase in the use of upper gastrointestinal series and ultrasonography in particular.

Conclusions: The clinical presentation of HPS has not actually changed despite the easier accessibility of GI imaging studies. However, the one significant change is the low percentage of pyloric tumors palpated, probably due to declining clinical skills, accompanied by earlier utilization of imaging studies. The use of imaging and laboratory studies did not change the age at diagnosis but may have shortened the time for diagnosis and reduced the postoperative stay. Imaging and laboratory studies may be helpful for the subgroup with a non-classical clinical presentation.