My 8 yr old was hospitalized 2 days in December due to severe vomiting and dehydration...diagnosed possible UTI, elevated white cell count, and ultrasound showed swollen left kidney. She was on antibiotics for 2 weeks and has been completely 100% fine since. We had a follow up ultrasound yesterday and Dr just called staying she wants us to have a second opinion with the children's hospital nephrologist. How concerned should I be?