My ultrasound suggest i have infection in both kidneys. is it more common to have an infection in one kidney or both? are there any differences in the potential causes of both? i.e is it less likely to be obstruct.? creatinine is mild elev egfr norma?

Need to see urologist for evaluation. Family history of kidney disease? Do family tree. Check for diabetes.

Kidney infection, pyelonephritis, is more common in one kidney but it's not rare to have bilateral pyelonephritis. Usually, the infection starts in the bladder (cystitis) then it ascends to either or both kidneys. Mild acute kidney injury with slightly elevated serum creatinine because both kidneys are sick at the same time. With unilateral pyelonephritis, serum creatinine is usually normal.