Infant with hypoplastic left heart syndrome on prostaglandin E to keep their ductus arteriosus patent who is continuously vomiting with feeds

UGI and US of prostaglandin E induced gastritis
Two lateral images from an upper GI (above) show persistent narrowing of the pylorus causing relative gastric outlet obstruction. Sagittal (left below) and transverse (right below) US of the pylorus shows the central echogenic gastric mucosa to be thickened and the pyloric muscle outside of it to be normal in diameter. The patient was also noted to be malrotated.

The diagnosis was prostaglandin E induced gastritis.