Reflux nephropathy

Reflux nephropathy

Definition:

A condition in which damage to the internal kidney structures occurs from the retrograde (backward) flow of urine into the kidney.

Alternative Names:

Chronic atrophic pyelonephritis; Vesico-ureteric reflux; Nephropathy - reflux; Ureteral reflux

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 4 out of 1,000 asymptomatic individuals. However, in infants and children who experience urinary tract infections, its prevalence approaches 40 to 50%. 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.

Symptoms:

repeated urinary tract infections in a female
a single urinary tract infection in a male
flank pain, back pain, or abdominal pain
urinary frequency/urgency increased
need to urinate at night
burning or stinging with urination
feeling of incomplete emptying of the bladder
blood in the urine
dark or foamy urine

Additional symptoms that may be associated with this disease:

Note: The disorder may not cause symptoms.

Signs and tests:

The blood pressure may be elevated, and there may be signs and symptoms of chronic renal failure.

Other tests include:

blood pressure
kidney ultrasound
serum, BUN
serum, creatinine
creatinine clearance
urinalysis or 24-hour urine studies that show elevated urine protein levels
urine culture that shows infection.
radionuclide cystogram may show vesicoureteric reflux or hydronephrosis (distention of the kidney from fluid accumulation in the renal pelvis)
IVP that shows hydronephrosis, a small kidney, or scarring of the kidney
Abdominal CT scan or ultrasound of the kidneys or abdomen that shows hydronephrosis, reflux, a small kidney, or scarring.
A voiding cystourethrogram (VCUG) definitively diagnoses vesicoureteric reflux

Treatment:

Simple, uncomplicated reflux (called primary reflux) less than Grade III may be treated by:

careful watching
repeated urine cultures
antibiotics to prevent infection
annual ultrasound of kidneys to follow development

More severe reflux may require surgery. This can include:

ureteral reimplantation
reconstructive repair

Expectations (prognosis):

The outcome varies. Most cases of vesicoureteric reflux resolve spontaneously. However, the damage to the kidney may be permanent. If only one kidney is involved, the other kidney may continue to function adequately.

Reflux nephropathy may cause as many as 20% of the cases of renal failure in children and young adults.

Complications:

permanent damage to one or both kidneys
chronic renal failure if both kidneys are involved
- progressing to end-stage renal disease
chronic or recurrent urinary tract infection
nephrotic syndrome
hypertension
pyelonephritis
renal scarring
persistent reflux
obstruction of the ureter following surgery

Calling your health care provider:

Call your health care provider if symptoms indicate reflux nephropathy may be present.

Call your health care provider if decreased urine output or other new symptoms develop.

Prevention:

Surgical reimplantation of the ureter(s) into the bladder may be performed to stop reflux nephropathy. This diminishes the frequency and severity of urinary tract infections.

The prompt treatment of conditions that cause reflux of urine into the kidney may prevent reflux nephropathy from developing.

Review Date: 11/30/2001
Reviewed By: Andrew Koren, M.D., Department of Nephrology, NYU-Mount Sinai Medical Center, New York, NY. Review provided by VeriMed Healthcare Network.

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