What condition is characterized by a narrowing of the pylorus, affecting the stomach?

Pyloric stenosis is a condition marked by the narrowing of the pylorus, which is the opening from the stomach into the small intestine. This narrowing can lead to significant complications as it obstructs the passage of food from the stomach. Symptoms often include projectile vomiting, dehydration, and electrolyte imbalances, especially in infants where this condition is most commonly diagnosed.

The focus on the pylorus distinguishes this condition from others listed, which involve different parts of the gastrointestinal tract or different pathologies. For instance, gastritis refers to the inflammation of the stomach lining, peptic ulcers involve sores that develop on the stomach lining or the upper part of the small intestine, and colitis involves inflammation of the colon. None of these conditions are directly related to the narrowing of the pylorus, making the correct identification of pyloric stenosis essential.