What is the age of presentation of pyloric stenosis?

Ans. is 'c' i.e., At 3 weeks of age Clinical manifestations of congenital hypertrophic pyloric stenosis* Pyloric stenosis is usually not present at birth.* Nonbillous 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 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.* In early stages the kidneys are able to compensate by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate, however as the body stores of sodium and potassium becomes depleted, these ions are selectively retained while hydrogen is excreted in urine, causing the paradoxical aciduria. This aggravates the alkalotic stage.