Hypertrophic Pyloric Stenosis in Infants Fed via Transpyloric Tube : Three Case Reports

Hypertrophic pyloric stenosis (HPS) is a well-known cause of gastric outlet obstruction in infants. However, its etiology is still controversial. Our experience has let us to consider that transpyloric (TP) tube feeding may be a potential cause of HPS. We report 3 cases of HPS in the context of TP tube feedings. All 3 patients had severe fundamental surgical disease and required enteral nutritional support via TP tube for an extended period. Within several months of TP tube placement, their gastric residuals gradually increased and a small amount of non-bilious vomiting occasionally occurred. Ultrasonography revealed gastric outlet obstruction due to hypertrophied pyloric muscles. All 3 infants required pyloromyotomy. The total duration of TP tube insertion ranged from 40 to 146 days. Of the 107 patients who received enteral nutrition support via TP tube at the National Center for Child Health and Development in the past 8 years, 3 (2.8%) developed HPS, an incidence approximately 15 times higher than the overall prevalence of infantile HPS in Japan, which ranges from 1 to 2 per 1000 live births (0.1-0.2%). To the best of our knowledge, only 16 cases of HPS that were considered to be related to TP tube feedings have been previously reported. HPS is a very rare complication, but one that must be taken into account when symptoms of delayed gastric emptying are seen during TP tube feedings.