Which symptom is a clinical manifestation of pyloric stenosis in a 10-day-old infant?

Projectile vomiting after feedings is a hallmark symptom of pyloric stenosis in infants. This condition occurs when the pylorus, the opening from the stomach to the small intestine, becomes narrowed, obstructing the flow of food into the intestine. As a result, when the infant feeds, the stomach fills with milk, but the narrowed pylorus causes an inability to effectively pass that milk into the intestine. This leads to forceful, projectile vomiting, which often occurs shortly after feeding.

In the context of an infant who is only 10 days old, the presence of this symptom is particularly significant, as pyloric stenosis typically presents between 2 to 8 weeks of age. The projectile nature of the vomiting distinguishes it from the typical regurgitation that can occur in many infants after feeding, making it a key sign for healthcare providers to recognize.

Other symptoms, such as diarrhea, colic, or fever, do not align with the typical presentation of pyloric stenosis and would likely suggest other gastrointestinal issues or infections rather than a blockage at the pylorus. Thus, recognizing projectile vomiting as a clinical manifestation allows for timely diagnosis and intervention, which is crucial in managing pyloric stenosis effectively.