A 4-week-old male infant presents with progressive, non-bilious projectile vomiting after feeding for the past week. He is visibly hungry immediately after vomiting. Physical examination reveals an olive-shaped mass in the epigastrium. Laboratory studies show hypochloremic, hypokalemic metabolic alkalosis. Which of the following is the most appropriate initial management step?

The correct answer to the question "A 4-week-old male infant presents with progressive, non-bilious projectile vomiting after feeding for the past week. He is visibly hungry immediately after vomiting. Physical examination reveals an olive-shaped mass in the epigastrium. Laboratory studies show hypochloremic, hypokalemic metabolic alkalosis. Which of the following is the most appropriate initial management step?" is Option C: Initiate intravenous fluid resuscitation and electrolyte correction.

The other options — A) Perform a barium swallow study, B) Conduct an urgent endoscopic evaluation, D) Schedule for urgent pyloromyotomy — are incorrect for this USMLE Exam Prep question. As explained above: This is a classic presentation of hypertrophic pyloric stenosis. While surgical pyloromyotomy is the definitive treatment, the immediate priority is to correct the dehydration and severe electrolyte …