The changing presentation of pyloric stenosis.

Metabolic abnormalities described in pyloric stenosis are now rare, probably because of prompter recognition of the disease. This report reviews the trend in presentation over three decades. All infants treated for pyloric stenosis during three mid-decade target periods were reviewed. Comparison between the 1975 group and the 1985 group and between the 1995 group and previous decades were designed to identify the impact of ultrasonography, since this modality has only been available in the last decade. Parameters included age at diagnosis and incidence of water and electrolyte imbalance as measures of delay in presentation. Two hundred eighty-three patients were reviewed. Mean age (weeks) at presentation was 5.4+/-3.0 in 1975, 4.6+/-2.0 in 1985, and 3.4+/-1.3 in 1995 (P < .05, ANOVA). Overall, 88% had no electrolyte anomalies on admission. There was no statistical difference in frequency of abnormal results between the three decades. Total and postoperative hospitalization was significantly shorter in the recent period: in 1985, 5.34 and 4.36 days; in 1985, 4.48 and 3.4 days; and in 1995, 3.8 and 2.8 days. These data show that pyloric stenosis is now recognized earlier than in previous decades. The availability of ultrasonography cannot solely be credited for earlier diagnosis, since this trend was already apparent before its introduction. The "classic" metabolic derangements associated with pyloric stenosis have been highly uncommon for the past three decades.