1. A 6-year-old girl presents with vomiting and bloody diarrhea for 2 days. Physical examination reveals T 37.80C, PR 120/min, BP 128/90 mmHg, dry lips. Initial investigations show Hb 9 g/dL, WBC 18,000 (N 80, L 20%), platelets 80,000/cu mm, 2+ schistocytes; UA: sp gr 1.020, 2+ protein, RBC 10-20, WBC 5-10/HPF; BUN 35, and Cr 2 mg/dL.Which of the following is the most likely diagnosis? *