🏥 USMLE Exam Prep

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?

A Perform a barium swallow study
B Conduct an urgent endoscopic evaluation
C Initiate intravenous fluid resuscitation and electrolyte correction
D Schedule for urgent pyloromyotomy

✓ Correct Answer: Option C

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 imbalances (hypochloremic, hypokalemic metabolic alkalosis) with intravenous fluids before surgery.

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