IHPS- a common case out there, a rare one here!


In western countries, IHPS is the most common cause of gastric outlet obstruction in infantile period. However, only 27 cases were reported in Thailand, last year. (Data from the National Survey, conducted by Prof. Dr. Pittaya Chandrakamol) The disease occurs more common in the first child, having male to female ratio ~ 2:1-5:1. Typical presentation is non-bilious vomiting, occurring at 2 to 8 weeks of age (peak3-5 weeks). Some may have upper GI bleeding and 2-5% have hyperbilirubinemia owning to the deficiency of glucoronyl transferase. Electrolytes changes usually appear hypochloremic, hypokalemic metabolic acidosis. Pyloric tumor, which is an olive mass at epigastrium can be palpated in 75% of the cases. Ultrasonography by experienced hands help much in the identification of the impalpable mass. Criteria for diagnosis are pyloric muscle thickness > 4 mm, pyloric canal length > 16 mm and may add pyloric diameter > 14 mm. Besides this, an upper GI study can be used effectively. Typical signs are called “string sign” and “inverted three” figure.

Operative treatment: Standard incision is a transverse-right upper quadrant one. Pylorus should be brought up into the incision. Serosa on the anterior wall of of the hypertrophied pylorus is incised with a scalpel from just proximal to the prepyloric vein to the antrum, approximately one centimeter proximal to the hypertrophied muscle. 



Use the handle of scalpel or Benson’s spreader to spread out muscle until the mucosa is seen. Most incomplete pyloromyotomies result from failure to extend the incision far enough proximally to the antral side. In case of accidentally entrance into the lumen, it should be closed with fine absorbable suture. Omental grafting may be added. Another incision is then made at the posterior aspect, 180 degree from the closed one.

A five-week old male infant presents to you with non-bilious projectile vomiting after almost every feedings. Physical examination revealed a thumb-sized mass just under the right lobe of liver and visible peristaltic waves at left upper quadrant. No abdominal distension is evidenced. The most likely diagnosis is;(fifth year, 2001)

  •  duodenal atresia

  •  infantile hypertrophic pyrolic stenosis

  •  midgut volvulus

  •  gastroesophageal reflux

  •  foreign body ingestion

Suggested further reading for surgical residents:
Dillon PW, Cilley RE. Lesion of the stomach. in Ashcraft