Etiology of Chronic Pyelonephritis
Relapsing Acute Pyelonephritis:
Recurrent acute pyelonephritis in childhood results
in renal scarring. New renal scars develop seldom after the age of 5 years, but are possible until puberty. The frequency of febrile urinary tract infections in children correlates with the severity of the scarring and the risk of chronic pyelonephritis. See also section acute pyelonephritis.
Vesicoureteral Reflux:
Since vesicoureteral reflux (VUR) causes recurrent urinary tract infections, VUR is also an important risk factor for chronic pyelonephritis (reflux nephropathy). The severity of chronic pyelonephritis correlates with the severity of vesicoureteral reflux and reflux nephropathy is a common cause of end-stage renal disease in children.
In some cases, however, severe vesicoureteral reflux does not lead to chronic pyelonephritis. In animal experiments, only vesicoureteral reflux with infected urine causes renal scarring, sterile reflux is not harmful. This finding was confirmed in human clinical trials and is the basis for successful antibiotic prophylaxis in vesicoureteral reflux.
Neurogenic Bladder Dysfunction:
Neurogenic bladder dysfunction may lead, comparable to vesicoureteral reflux, to chronic pyelonephritis by ascending infections and intrarenal reflux. Important risk factors are high bladder pressures in the storage phase or during micturition.
Other Risk Factors:
Diabetes mellitus, nephrolithiasis, chronic catheterization.