Sonia is a 15 year old teen who plays varsity basketball and is generally well and up-to-date with health maintenance. She presents for an urgent care visit with a 6-h history of sudden onset nausea, with multiple episodes of vomiting, abdominal cramping and 2 episodes of diarrhea with stool described as light to dark brown without visible blood. Her VS are within normal limits and mucous membranes are slightly dry. She has slightly hyperactive bowel sounds and mild exceptional tenderne...