A baby, who was apparently normal at bih, develops persistent regurgitation and vomiting in the second and third weeks of life. No fever is present and hematologic studies and blood chemistries are normal. Which of the following therapies is most likely to be effective in this case?
**Core Concept**
The baby's symptoms suggest a gastrointestinal motility disorder, specifically gastroesophageal reflux disease (GERD) or pyloric stenosis, given the age and presentation of persistent regurgitation and vomiting.
**Why the Correct Answer is Right**
The most likely diagnosis is pyloric stenosis, characterized by hypertrophy of the pyloric muscle, which leads to obstruction of gastric outflow. This results in projectile vomiting, which is often non-bilious. The normal hematologic and blood chemistry studies help rule out other causes of vomiting such as infectious or metabolic disorders. The effective therapy for pyloric stenosis is **pyloromyotomy**, a surgical procedure that involves incising the hypertrophied pyloric muscle to relieve the obstruction.
**Why Each Wrong Option is Incorrect**
**Option A:** Metoclopramide is a prokinetic agent that can be used to treat GERD and other gastrointestinal motility disorders, but it is not the most effective treatment for pyloric stenosis.
**Option B:** Ryle's tube placement is a supportive measure that can be used in cases of severe dehydration or electrolyte imbalance, but it does not address the underlying cause of the vomiting.
**Option C:** Gastric lavage is a procedure that involves flushing the stomach with fluid to remove contents, but it is not indicated in this case as the vomiting is caused by a mechanical obstruction rather than poisoning or overdose.
**Clinical Pearl / High-Yield Fact**
Pyloric stenosis is a classic cause of projectile vomiting in infants, and it often presents in the second or third week of life. The "rule of threes" is a useful mnemonic to remember the classic presentation: vomiting occurs in the second or third week of life, is projectile in nature, and is often associated with a palpable "olive" mass in the right upper quadrant.
**Correct Answer:** C. Pyloromyotomy.