Reflux nephropathy

Alternative names:

chronic atrophic pyelonephritis; nephropathy - reflux; ureteral reflux; vesico-ureteric reflux

Definition:

A condition in which damage to the internal kidney structures occurs from the backup of urine into the kidney.

Causes, incidence, and risk factors:

Reflux nephropathy occurs when the normally one-direction-only valve-like mechanisms between the ureters and bladder fail. This allows urine to flow back up the ureter directly to the kidney. If the bladder is infected or the urine contains bacteria this exposes the kidney to the possibility of infection (pyelonephritis). In addition, the pressure in the bladder is generally higher than that in the kidney, especially so when urinating. This exposes the kidney to unusually high pressures and over time will damage the kidney and cause scarring.

Reflux may occur when the ureters tunnel only a short distance within the bladder wall before opening into the bladder. Urine pressure in the bladder normally keep the tunnels pressed closed, but if the bladder wall tunnels are short or absent, pressure within the bladder forces urine back up the ureter.

Reflux may be associated with other conditions including bladder infections, bladder stones, bladder outlet obstruction, neurogenic bladder, and abnormal ureters or abnormal number of ureters.

Reflux nephropathy may not produce any obvious signs. Reflux is often discovered when a child with repeat or suspect bladder infections is evaluated radiologically. If reflux is discovered the child's siblings may also be evaluated, because reflux can run in families.

The degree of reflux, often separated into five different grades may help determine how the condition is treated. Simple, uncomplicated reflux often falls into the Grade I or II category.

Reflux nephropathy may also occur from temporary swelling after surgical reimplantation of ureters during kidney transplant or because of trauma to the ureter.

Reflux nephropathy occurs in about 1 out of 1,000 people. It is severe enough to cause reflux nephropathy in approximately 4 out of 10,000 people. Reflux nephropathy may lead to chronic renal failure and end-stage renal disease. The symptoms may not be present if only one kidney is affected or may be those of urinary tract infections, nephrotic syndrome, or chronic renal failure.

The risk factors include a personal or family history of reflux, congenital abnormalities of the urinary tract, and recurrent urinary tract infections.