Infantile hypertrophic pyloric stenosis and hydronephrosis: is there an association?

Infantile hypertrophic pyloric stenosis is a common condition requiring surgical intervention during the first few weeks of life. The incidence of infantile hypertrophic pyloric stenosis ranges from 0.13 to 0.4% of live births in the United States, Britain and Scandinavia. Associated anomalies have been described in 6 to 33% of the cases in the central nervous system, gastrointestinal tract and heart. An association of infantile hypertrophic pyloric stenosis with urinary tract anomalies has not been previously documented. A review of 422 patients with infantile hypertrophic pyloric stenosis revealed urinary tract anomalies in 6 (10 renal units), including 4 renal units with vesicoureteral reflux and 9 with hydronephrosis. This incidence of 1.4% is greater than the 0.2% incidence expected in the general population. This 7-fold increase in urinary tract anomalies in patients with infantile hypertrophic pyloric stenosis suggests an association between the two and warrants further investigation. Serious consideration should be given to obtaining renal ultrasound examinations in patients with infantile hypertrophic pyloric stenosis.