Answer and Explanation 3

3.  Choice A is the correct answer.  This patient is presenting with a history concerning for pyloric stenosis.  The current recommendation for diagnostic imaging in abdominal ultrasound.  Typically pyloric stenosis presents around 6 weeks as projectile vomiting refractory to anti-emetics.  The highest incidence is in caucasian males.  Ranitidine would be helpful in GERD which does not present like this.  KUB would be helpful to screen for a volvulus, midgut malrotation, or toxic megacolon.  A scrotal ultrasound would be helpful if you were suspicious for undescended testicles or testicular torsion.