• infant;
  • pyloric stenosis;
  • pyloromyotomy;
  • vomiting


Increased awareness of idiopathic hypertrophic pyloric stenosis (IHPS) and readily available ultrasonographic diagnosis might mean that ‘classic’ presentations are becoming less common. We sought to describe the epidemiology, clinical features and outcomes of children with IHPS in the modern era. A retrospective case review of all cases of IHPS presenting to a single tertiary paediatric hospital over an 11 year period was conducted. Inclusion criteria were met by 329 children with confirmed IHPS. Eighty-four per cent of patients were male and 19% were born premature. Premature infants tended to present later, reflecting postmenstrual age. The median age at presentation was 5 weeks (range 0–31) with median symptom duration of 7 days (range 1–95). At least one classic symptom or sign was present in 87% of infants but only 14% had the classic triad (projectile vomiting, palpable olive and visible peristalsis). Elevated bicarbonate was present in 61% of blood samples, whereas hypochloraemia was found in only 29%. Ultrasound confirmed the diagnosis in 89%. Surgical techniques were similar in outcome, except that incomplete pyloromyotomy was more common with the laparoscopic compared with periumbilical approach (6% vs 1%, P= 0.023). IHPS occurs more frequently in male and ex-premature infants. It commonly presents without the full spectrum of ‘classic’ symptoms and signs. Given the availability of ultrasound diagnosis, IHPS should be considered in all babies with any one of the classic findings.