IS Case 176: Hypertrophic pyloric stenosis
Imaging Sciences URMC 2008
Publication Date: 2009-05-21
Hypertrophic pyloric stenosis (HPS) is caused by congenital hypertrophy of the circular muscle of the pylorus. The etiology of the disorder is unknown. Its incidence is approximately 2 to 5 per 1000 live births with a male to female ratio of 4-6:1. First-born males are most frequently afflicted and there is a slight increased risk in relatives. Whites are more often affected than other races.
Patients usually present from 3-6 weeks with non-bilious projectile emesis, difficulty feeding, and failure to thrive. Physical examination often reveals a palpable 'olive' mass in the epigastric region corresponding to the palpable hypertrophied circular muscle. Exaggerated gastric peristalsis can be seen through the anterior abdominal wall.
The major differential diagnoses for infants presenting in the emergency room is with malrotation, which often presents with bilious vomiting. Although ultrasound can be used for diagnosis of HPS, a negative ultrasound will often necessitate an upper GI to help exclude the more serious malrotation. Thus, the fluoroscopic examination can be used as the initial evaluation of both of these conditions. On the other hand, ultrasound can be used to directly visualize the pyloric musculature or help confirm HPS in equivocal cases.
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- Reid, Janet. Hypertrophic pyloric stenosis. Emedicine, June 29, 2007. http://emedicine.medscape.com/article/409621-overview