I Recently Had An Abdominal Ultrasound And It Showed An

I recently had an abdominal ultrasound and it showed an enlarged liver and a THIN right renal cortex. When i asked my doctor about it she said it could be caused from a virus.I am no doctor and dont claim to be but with all the research i have done on renal cortex thinning has not mentioned being caused by a virus. Please help should I get a second opinion.