CONFUSION AND DOUBT

Abstract

Purpose: Congenital hypertrophic pyloric stenosis (CHPS) in early infancy can often be confused, particularly in its early stages of evolution, with severe gastro-oesophageal reflux. Previous studies have shown that a significant proportion of infants with CHPS have varying degrees of gastro-oesophageal reflux with an associated oesophagitis. Our aim was to evaluate the effects of empiric anti-reflux therapy on the clinical course and diagnosis of infants who developed CHPS. Methods: We carried out a retrospective case-note review of all infants with a final confirmed diagnosis of CHPS presenting at a district hospital over a nine-year (1995–2003) period. Results: 48 infants (41 male, 7 female) were identified among whom 11 had received empiric anti-reflux treatment following an initial clinical diagnosis of gastro-oesophageal reflux (median treatment duration-3 days; IQR: 2–12.5). The time period between physician contact and final diagnosis was significantly longer in the group of treated infants in comparison to the group that received no medication (3 versus 2 days; two-tailed p-0.047; Mann-Whitney). Anti-reflux therapy was associated with not only increased readmission rates (45.5% versus 10.8%; two-tailed p-0.021; Fisher's exact test) but also a lesser degree of metabolic alkalosis, though the latter was not statistically significant. Serum potassium and chloride levels as well as the ultrasonic measurements of pyloric canal length and muscle thickness were no different in the two groups. Conclusions: Empiric anti-reflux treatment can be associated with a significant delay in diagnosis of CHPS. The increased readmission rate for those on anti-reflux treatment implies an increased rate of initial misdiagnosis in treated infants. Both these factors are likely to increase parental stress around the time of diagnosis. It may also alter the biochemical profile away from the typical hypochloremic metabolic alkalosis. Physicians should be aware of the increased potential for diagnostic confusion in the presence of anti-reflux treatment.