Merck Manual

Please confirm that you are a health care professional

Loading

Vesicoureteral Reflux (VUR)

By

Ronald Rabinowitz

, MD, University of Rochester Medical Center;


Jimena Cubillos

, MD, University of Rochester School of Medicine and Dentistry

Last full review/revision Feb 2019| Content last modified Feb 2019
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Topic Resources

Vesicoureteral reflux is retrograde passage of urine from the bladder back into the ureter and sometimes also into the renal collecting system, depending on severity. Reflux predisposes to urinary tract infection, often recurrent. Evaluation includes ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then fluoroscopic voiding cystourethrography (VCUG). Treatment depends on the cause and severity.

Etiology

Vesicoureteral reflux (VUR) is most often due to congenital anomalous development of the ureterovesical junction. Incomplete development of the intramural ureteral tunnel causes failure of the normal flap valve mechanism at the ureterovesical junction that permits reflux of bladder urine into the ureter and renal pelvis. Reflux can occur even when the tunnel is ordinarily sufficient if bladder pressure increases due to bladder outlet obstruction or dysfunctional voiding. Dysfunctional voiding includes infrequent voiding, constipation, or both, which may prolong resolution of VUR.

Pathophysiology

Reflux of urine from the bladder into the ureter may damage the upper urinary tract by bacterial infection and occasionally by increased hydrostatic pressure. Bacteria in the lower urinary tract can easily be transmitted by reflux to the upper tract, leading to recurrent parenchymal infection with potential scarring. Renal scarring can eventually cause hypertension and sometimes renal dysfunction. VUR is a common cause of urinary tract infection (UTI) in children; about 30 to 40% of infants and toddlers with UTI have VUR.

Symptoms and Signs

Children typically present with a history of fetal hydronephrosis or with a UTI or appear as part of a sibling screening. Rarely, children present with hypertension, which is more commonly a long-term consequence of renal scarring. Children with UTI may have fever, abdominal or flank pain, dysuria, frequency, urgency, wetting accidents, or rarely hematuria.

Diagnosis

  • Ultrasonography

  • Voiding cystourethrography (VCUG)

  • Sometimes radioisotope scan

Urinalysis and culture are done to detect infection. In infants and young children, a catheterized specimen is usually required.

Evaluation includes ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then fluoroscopic VCUG. Renal ultrasonography is used to evaluate kidneys for size, hydronephrosis, and scarring. VCUG is used to diagnose VUR and to evaluate for other bladder abnormalities. A radioisotope cystogram (radionuclide cystography) may be used to monitor reflux. Renal cortical involvement with acute infection or scarring is best diagnosed with succimer (dimercaptosuccinic acid) nuclear scans when indicated. Urodynamic studies, when appropriate, may show elevated intravesical pressure.

Reflux findings on VCUG are graded on a scale from I to V (see table Grades of Vesicoureteral Reflux). The degree of reflux can be affected by bladder capacity and bladder dynamics.

  • Mild: Grades I and II

  • Moderate: Grade III

  • Severe: Grades IV and V

Table
icon

Grades of Vesicoureteral Reflux*

Grade

Characteristics

I

Only the ureters are involved, but not the renal pelvis.

II

Reflux reaches the renal pelvis, but the calyces are not dilated.

III

The ureter and renal pelvis are dilated, with minimal or no blunting of calyces.

IV

Dilation increases, and the sharp angle of the calyceal fornices is obliterated.

V

The ureter, pelvis, and calices are grossly dilated.

Papillary impressions frequently are absent.

*As defined by the International Reflux Study Committee.

Treatment

  • Sometimes antibiotic prophylaxis

  • Sometimes injection of a bulking agent or ureteral reimplantation

Mild to moderate vesicoureteral reflux often resolves spontaneously over months to several years. It is very important to keep children free of infection. Previously, children with mild to moderate VUR were given daily antibacterial prophylaxis, but there is currently no consensus on this practice. Most pediatric urologists recommend prophylactic antibiotics for severe VUR at all ages, for VUR grades III to V in children < 2 years, and for children with recurrent febrile UTIs independent of VUR grade. There are multiple age- and weight-based recommendations for antibiotics, but, typically, children are given trimethoprim/sulfamethoxazole at bedtime, nitrofurantoin at dinnertime, or cephalexin twice daily.

Severe vesicoureteral reflux accompanied by high intravesical pressures is treated with anticholinergic drugs (eg, oxybutynin, solifenacin succinate) and rarely surgery (such as botulinum toxin or bladder augmentation). Patients with bowel and bladder dysfunction benefit from behavioral modification with or without biofeedback.

Symptomatic reflux (recurrent infections, impaired renal growth, renal scarring) is treated with endoscopic injection of a bulking agent (eg, dextranomer/hyaluronic acid) or ureteral reimplantation.

Monitoring

History, physical examination (including BP measurement), laboratory testing with urinalysis (to look for hematuria and proteinuria) and serum creatinine, and imaging using VCUG and ultrasonography are done at regular intervals depending on the child's age and the severity of the reflux and associated complications. Typically, children < 2 years have ultrasonography every 4 to 6 months (more frequently in children with significant nephropathy visible on ultrasonography); older children have ultrasonography every 6 to 12 months. VCUGs may be repeated every 1 to 2 years (longer intervals for higher grade VUR, bilateral VUR, and/or older children).

In addition, toilet-trained children should be assessed at each visit for constipation and infrequent voiding, incontinence, urinary urgency, and nocturnal enuresis, which are common signs of elimination dysfunction, and treated as needed with behavioral modification and/or drug therapy.

Key Points

  • Vesicoureteral reflux (VUR) is most often due to congenital anomalous development of the ureterovesical junction.

  • Reflux of urine from the bladder into the ureter may cause bacterial infection of the upper urinary tract; about 30 to 40% of infants and toddlers with UTI have VUR.

  • Diagnose by using VCUG.

  • Monitor by using serial ultrasonography and VCUGs.

  • Mild to moderate VUR often resolves spontaneously, but more serious disease may require surgical intervention.

  • Children with newly diagnosed VUR are given prophylactic antibiotics depending on the severity and clinical course.

  • Assess toilet-trained children for dysfunctional elimination and treat them appropriately.

Drugs Mentioned In This Article

Drug Name Select Trade
FURADANTIN, MACROBID, MACRODANTIN
No US brand name
VESICARE
DITROPAN XL
KEFLEX
CHEMET
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Also of Interest

Videos

View All
Overview of Coarctation of the Aorta
Video
Overview of Coarctation of the Aorta
3D Models
View All
Cystic Fibrosis: Defective Chloride Transport
3D Model
Cystic Fibrosis: Defective Chloride Transport

SOCIAL MEDIA

TOP