A nurse is caring for a newborn who may have pyloric stenosis. Which of the following manifestations should the nurse expect?

A. Presence of Dance sign. Dance sign (an empty right lower quadrant on palpation) is associated with intussusception, not pyloric stenosis. Pyloric stenosis is characterized by hypertrophy of the pyloric sphincter, leading to gastric outlet obstruction. B. Projectile vomiting. Forceful, non-bilious projectile vomiting is the hallmark symptom of pyloric stenosis. It occurs due to the narrowing of the pyloric sphincter, preventing stomach contents from passing into the small intestine. Vomiting usually begins around 2 to 6 weeks of age and worsens over time. C. Always seems full. Infants with pyloric stenosis actually experience hunger and irritability after vomiting because food is not reaching the intestines for digestion and absorption. D. Excessive weight gain. Instead of gaining weight, infants with pyloric stenosis often experience weight loss or poor weight gain due to repeated vomiting and inadequate nutrient absorption.