Final answer:
An infant with non-bilious vomiting and palpable olive has hypertrophic pyloric stenosis, characterized by vomiting and metabolic alkalosis, and is treated surgically via pyloromyotomy.
Step-by-step explanation:
A four-week-old infant with non-bilious vomiting and a palpable olive in the abdomen is likely suffering from hypertrophic pyloric stenosis (HPS). HPS is a condition in which the muscle of the pylorus – the outlet from the stomach to the intestine – becomes abnormally thickened, causing obstruction and leading to forceful vomiting.
Diagnosis
The classic symptoms of projectile vomiting and a palpable mass in the abdomen (“olive”) combined with ultrasound findings are used to diagnose HPS. The metabolic complication associated with this condition is hypochloremic, hypokalemic metabolic alkalosis, which occurs secondary to vomiting and loss of stomach acid.
Treatment
The treatment for HPS is surgical and involves a procedure called pyloromyotomy, in which the thickened pyloric muscle is split to allow passage of food from the stomach to the small intestine. This is a corrective measure that has high success rates.