A 9 year old girl presents to the clinic with vomiting for 8 hours.  She has vomited 3 times and quite a bit in volume. The emesis is clear and not projectile. She does not have any reported abdominal pain. She has voided 2 times today and has had one normal bowel movement. Earlier this morning she was playing baseball and was struck by another player. There was no witnessed loss of consciousness. She sustained no obvious injuries. Physical Examination: She looks tired.  Abdomen is soft. On auscultation, bowel sounds are normal. On palpation it is non-tender and there are no masses or organomegaly. The remainder of the physical examination is normal.