Delayed presentation of infantile hypertrophic pyloric stenosis: a case report

Hypertrophic pyloric stenosis (HPS) is characterized by hyperplasia of the smooth muscle fibers of the pylorus, leading to narrowing of the pyloric canal and obstruction of gastric emptying. It is the most common cause of surgical vomiting in infants. Classically, infants present with non-bilious projectile vomiting; the child is hungry after vomiting and suckles well but becomes dehydrated and wasted. IHPS usually presents between the 3rd and 5th weeks of life. Cases of delayed presentation are very rare (1/100,000) and usually diagnosis is delayed. We are reporting atypically late age presentation of infantile hypertrophic pyloric stenosis case.

We report the case of a 10-month-old male infant who presented with non-bilious vomiting of nine months' duration. On examination, he was wasted and stunted, with no palpable "olive." Abdominal ultrasound revealed a hypertrophied pyloric muscle. A diagnosis of hypertrophic pyloric stenosis was made, and Ramstedt's pyloromyotomy was performed. The infant resumed feeding eight hours postoperatively, with no recurrence of vomiting.

Infantile hypertrophic pyloric stenosis (IHPS) results from hypertrophy and hyperplasia of the circular muscle fibers of the pylorus, causing progressive narrowing of the gastric outlet and subsequent obstruction. It is one of the most common causes of non-bilious, projectile vomiting in infants, typically presenting between the second and eighth weeks of life. Aboagye et al. reported that 97.5 % of IHPS cases are diagnosed by 12 weeks of age, with a peak at around five weeks. Presentation beyond this window is unusual and often leads to diagnostic delays.

Delayed presentation of infantile hypertrophic pyloric stenosis is uncommon but critical to recognize. Clinicians should maintain a high index of suspicion for IHPS in infants with persistent vomiting, even beyond the typical age range. Early diagnosis and timely surgical intervention are essential to prevent complications and ensure favorable outcomes. This case highlights the importance of recognizing atypical presentations to avoid diagnostic delays.