What is chronic pyelonephritis and what is focal area scarring in the lower pole of the left kidney?

Chronic Pyelo. Chronic pyelonephritis is the result of any process in the kidney that causes prolonged inflammation and fibrosis (scarring). Common causes include: persistent or recurrent renal infections, vesicoureteral reflux (urine going backwards into the kidney), or urinary tract obstruction. A board certified urologist or nephrologist are the best doctors to review these types of findings.