Which of the following electrolyte abnormality can be seen in an infant with congenital hyperophic pyloric stenosis?
High-Yield Explanation
Infants with HPS present with nonbilious vomiting that becomes increasingly projectile over the course of several days to weeks. Infants with HPS develop a hypochloremic, hypokalemic metabolic alkalosis. Dehydration causes elevated hemoglobin and hematocrit. Mild unconjugated bilirubinemia occurs in 2%-5% of cases. The urine pH is high initially but eventually drops because hydrogen ions are preferentially exchanged for sodium ions in the distal tubule of the kidney as the hypochloremia becomes severe. Ref: Hackam D.J., Grikscheit T.C., Wang K.S., Newman K.D., Ford H.R. (2010). Chapter 39. Pediatric Surgery. In F.C. Brunicardi, D.K. Andersen, T.R. Billiar, D.L. Dunn, J.G. Hunter, J.B. Matthews, R.E. Pollock (Eds), Schwaz's Principles of Surgery, 9e.