My son was diagnosed with grade 4 and grade 5 reflux while in utero. He is now 11 months. His right side looked like it was almost resolved according to a ultrasound 3 weeks ago. But two months ago a nucular scan showed blockage in left ureter. (Left kidney showed worsening hydronephrosis on ultrasound and voiding cystogram). Today he spiked a fever so I took him to er and he has a kidney infection. This is his first infection and I m wondering how much damage if any can the infection have on his kidneys?
Sorry to hear the news. As left ureter has a block which is resulting in worsening HY Chat Doctor.  However, I need to know the degree of obstruction which you didn't mention... Till surgery could be done first the kidney infection has to be treated with iv antibiotics then he has to be kept on regular prophylactic antibiotics.