A nurse working at a clinic speaks on the telephone with a parent of a 2-month-old infant. The parent tells the nurse that the infant has projectile vomiting followed by hunger after meals. Which of the following responses by the nurse is appropriate?

Choice A reason: Switching formula does not address projectile vomiting followed by hunger, suggestive of pyloric stenosis, a mechanical obstruction. Changing formula may delay diagnosis and treatment, risking dehydration or malnutrition. Immediate clinical evaluation is needed to confirm the condition and plan surgical intervention, making this response inappropriate. Choice B reason: Frequent burping reduces air in the stomach but does not address projectile vomiting from pyloric stenosis, caused by pyloric muscle hypertrophy. This symptom requires surgical evaluation, not feeding adjustments. Burping is ineffective, as the obstruction persists, making clinical evaluation the priority to prevent complications. Choice C reason: Projectile vomiting with hunger in a 2-month-old suggests pyloric stenosis, requiring urgent clinical evaluation for diagnosis via ultrasound and surgical planning (pyloromyotomy). Prompt assessment prevents dehydration, electrolyte imbalances, and growth issues, making this the appropriate response to ensure timely intervention for this serious condition. Choice D reason: Oral rehydration solution treats dehydration but does not address the underlying cause of projectile vomiting, likely pyloric stenosis. This delays definitive surgical treatment, risking worsening dehydration or malnutrition. Clinical evaluation is critical to confirm the diagnosis, making rehydration a secondary, not primary, response to the symptoms.