What is a likely cause of a 2 week old with projectile vomiting and no fever?

Pyloric stenosis: Anytime a parent describes projectile vomiting, that child needs to be seen. Pyloric stenosis is a congenital problem where the outlet of the stomach thickens over the first months or so of life and creates an "outlet obstruction" leading to projectile vomiting. It is easily diagnosed with an ultrasound and is easily repaired surgically. This child needs to be seen.

See your MD: It could be a couple things, but the one the pediatrician needs to r/o is pyloric stenosis or non accidental trauma. Reflux is also a possibility.

Pyloric Stenosis: A full term child who is vomiting forcefully and not able to keep feeds down should be evaluated immediately. They may have an obstruction of the stomach which prevents the food from leaving the stomach. Please consult your physician immediately.