Chronic Pyelonephritis - Reflux nephropathy

This was called chronic pyelonephritis or atrophic pyelonephritis and it results from a combination of:

• vesicoureteric reflux, and
• infection acquired in infancy or early childhood.

Normally the vesicoureteric junction acts as a one-way valve, urine entering the bladder from above; the ureter is shut off during bladder contraction, thus preventing reflux of urine. In some infants and children - possibly even in utero - this valve mechanism is incompetent, bladder voiding being associated with variable reflux of a jet of urine up the ureter.

A secondary consequence is incomplete bladder emptying, as refluxed urine returns to the bladder after voiding. This latter event predisposes to infection, and the reflux of infected urine leads to kidney damage.

Typically there is papillary damage, interstitial nephritis and cortical scarring in areas adjacent to 'clubbed calyces'. Diagnosis is based on excretion urography, which shows irregular renal outlines, clubbed calyces and a variable reduction in renal size. The condition may be unilateral or bilateral and affect all or part of the kidney.

Reflux usually ceases around puberty with growth of the bladder base. Damage already done persists and progressive renal fibrosis and further loss of function occurs in severe cases even though there is no further infection. This condition does not develop in the absence of reflux and does not begin in adult life. Adult females with bacteriuria and a normal urogram can be reassured that kidney damage due to reflux nephropathy will not develop.

Chronic reflux nephropathy acquired in infancy predisposes to hypertension in later life and, if severe, is a relatively common cause of end-stage renal failure in childhood or adult life. Meticulous early detection and control of infection, with or without ureteral reimplantation to create a competent valve, can prevent further scarring and allow normal growth of the kidneys.

No proof exists that reimplantation surgery confers benefit. Only one small adequately controlled trial of surgery plus medical treatment versus medical treatment alone is available. No benefit was observed in the operated group.