A 8 year old girl is brought to the emergency room by EMS after having diarrhea for 5 days and feeling lethargic for the past 12 hours. She has a history of occasional constipation. Immunizations are up to date for age.  Family history reveals that the patient has an older brother with eczema. Social history is unremarkable. Upon examination, the patient appears unwell. The patient is responsive but lethargic. The neurological,respiratory, and skin exams appears normal. The cardiovascular examination shows normal heart sounds and no murmurs. Eyes are sunken, mucous membranes are dry, pulses are palpable, capillary refill is 4 seconds centrally. The abdominal examination reveals diffuse but non-peritonitic tenderness.