Chronic Pyelonephritis (CP)
Chronic pyelonephritis is characterized by renal inflammation and fibrosis induced by recurrent or persistent renal infection, vesicoureteral reflux, or other causes of urinary tract obstruction. The diagnosis of chronic pyelonephritis is made based on imaging studies such as ultrasound or CT scanning. It occurs almost exclusively in patients with major anatomic anomalies, most commonly in young children with vesicoureteral reflux (VUR). VUR is a congenital condition that results from incompetence of the ureterovesical valve due to a short intramural segment. VUR is present in 30-40% of young children with symptomatic UTIs and in almost all children with renal scars. It may also be acquired by patients with a flaccid bladder due to spinal cord injury.