26th April 2024

A 5-week-old male infant is brought in by his parents due to persistent vomiting for the past two weeks.

A 5-week-old male infant is brought in by his parents due to persistent vomiting for the past two weeks. His parents describe the vomiting as forceful and occurring shortly after feeding. He is being fed a combination of breast and bottled milk. They also report that the infant seems hungry again soon after vomiting. There has been a decrease in the frequency of his bowel movements and minimal weight gain since birth. On examination, the infant appears dehydrated and irritable. A palpable olive-like mass is noted in the epigastric region.

Investigations:

Blood tests show hypochloremic, hypokalemic metabolic alkalosis.

Which is the most likely diagnosis?