Gastrointestinal: Infantile hypertrophic pyloric stenosis

Abstract

Infantile hypertrophic pyloric stenosis causes gastric outlet obstruction because of anatomical changes around the pyloric canal. The most important change is abnormal thickening of the circular muscle that is often associated with redundant pyloric mucosa. The incidence ranges from 1 to 8 per 1000 live births and males are more commonly affected than females (ratio 4:1). The etiology remains unclear but cases cluster within families and associations have been reported with a variety of congenital disorders including Hirschsprung disease and esophageal atresia. The typical symptom is recurrent vomiting that develops 2–10 weeks after birth and is often associated with failure to thrive and dehydration. At least 70% of infants have an epigastric mass (‘olive’) and some have visible peristaltic waves. The diagnosis is usually confirmed by an abdominal ultrasound study that shows a ‘donut’ sign with thickening of the circular muscle to greater than 3 mm. Barium studies will also show gastric outlet obstruction but can be difficult in young infants and should be preceded by gastric aspiration. Definitive therapy is a Ramstedt pyloromyotomy that includes a longitudinal incision through the hypertrophied muscle down to the submucosa. Almost all infants have an excellent short and longer-term outcome. The patient illustrated below was a 12-year-old Chinese girl who was investigated because of episodes of abdominal pain and vomiting since the age of 4 years. There were no other significant medical problems. A barium study showed a large stomach with a narrow elongated pylorus (arrow) and ‘shoulders’ in the antrum of the stomach (Fig. 1). The appearance was consistent with hypertrophic pyloric stenosis. However, the diagnosis could not be confirmed by an upper abdominal ultrasound study. At endoscopy, pyloric narrowing prevented passage of the endoscope into the duodenum. She subsequently had an endoscopic ultrasound study that confirmed hypertrophy of circular muscle to 7 mm (Fig. 2). Attempted therapy using balloon dilators was unsuccessful and she was subsequently treated with a Ramstedt pyloromyotomy. This resulted in a rapid improvement in her symptoms. Contributed by