A 6 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 was previously well. Immunizations are incomplete.  Family history reveals that the patient has a sister with asthma. Social history is non-contributory. Upon examination, the patient appears dehydrated. 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 vague and diffuse pain.