A 5 year old boy is brought to the emergency room by EMS after having diarrhea for 5 days and feeling lethargic for the past 12 hours. He has an unremarkable past medical history. Immunizations are incomplete.  Family history reveals that all family members are healthy. 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. Mucous membranes are dry, pulses are palpable but weak, capillary refill is 5 seconds centrally and peripherally. The abdominal examination reveals vague and diffuse pain.