Hypertrophic Pyloric Stenosis

  • Etiology: hypertrophy of pylorus muscle
  • AXR: caterpillar sign due to hyperperistalsis
  • US: pyloric muscle > 3.5 mm thick, pyloric channel > 17 mm long
  • UGI: antrum + duodenal bulb deformity on upper GI: antral shouldering + pyloric beak / teat + tram track through pylorus
  • DDX: prostaglandin E induced gastritis

Cases of Hypertrophic Pyloric Stenosis

Upper GI and US of hypertrophic pyloric stenosis
Lateral images from an upper GI exam (above) show delayed passage of barium out of the stomach due to a thickened and elongated pylorus. A tram track sign of barium in the pyloric channel was seen (upper left) along with pyloric muscle shouldering on the antrum along with a pyloric beak (upper right). Sagittal (lower left) and transverse (lower right) US of the pylorus shows marked thickening of the peripheral hypoechoic pyloric muscle which measures 4.5 mm thick, as compared to the thin central hyperechoic pyloric mucosa. Elongation of the pyloric channel was also noted, measuring 25 mm in length.
Surgical image of hypertrophic pyloric stenosis
Surgical image shows delivery of the pylorus which is thickened, firm and blanched as opposed to its normal small, soft and pink consistency.