The metabolic derangement in congenital pyloric stenosis is –
Clinical manifestations of congenital hypertrophic pyloric stenosis 

Pyloric stenosis is usually not present at birth.
Nonbullous vomiting is the initial symptoms of pyloric stenosis.
The vomiting usually starts after 3 weeks of age, but symptoms may develop as early as the 1st week of life and as late as the 5 months of life.
Emesis may follow each feeding, or it may be intermittent.
After vomiting, the infant is hungry and wants to feed again.
Due to vomiting, there is a progressive loss of→ Fluid, Hydrogen ion, Chlorides
This results in hypochloremic metabolic alkalosis.
Serum potassium levels are usually maintained, but there may be a total body potassium deficit.
Jaundice (unconjugated bilirubin) is associated with a decreased level of glucuronyl transferase in 5% of patients.
Hypochloremic alkalosis
Hyperchloremic alkalosis
Hyperchloremic acidosis
Hypochloremic acidosis