Vesicoureteral Reflux Sequelae
Vesicoureteral reflux (VUR) is a condition in which urine flows backward from the bladder up the ureters toward the kidneys, either continuously (in more severe cases) or during voiding. VUR is most commonly diagnosed in childhood and, when significant, can contribute over time to kidney scarring, high blood pressure, protein in the urine, and reduced kidney function. The imaging finding known as “vesicoureteral reflux sequelae” refers to the long-term effects of past reflux seen on imaging in adulthood or later childhood—most often kidney scarring or focal atrophy (also called reflux nephropathy), which typically appears as areas of thinning or contour irregularity in the kidney. Many affected individuals have no active symptoms as adults, but recognition is important for long-term monitoring of blood pressure and kidney function.
What is it?
Vesicoureteral reflux (VUR) is a condition in which urine flows backward from the bladder up the ureters toward the kidneys, rather than only moving downward from the kidneys to the bladder as it normally does. Normally, the ureters enter the bladder wall at a specific angle and pass through the bladder muscle at a length that creates a one-way valve mechanism—when the bladder fills or contracts, the segment of ureter within the bladder wall is compressed, preventing backward flow. When this valve mechanism is inadequate, urine can reflux upward, particularly during bladder contraction (voiding) or when bladder pressure is high.
VUR is broadly divided into primary and secondary types.
Primary VUR is present from birth due to a congenital abnormality in the way the ureter enters the bladder—typically a shortened intramural (within-wall) segment of the ureter, which weakens the valve mechanism. It is often identified in childhood, most commonly during evaluation of urinary tract infections. Primary VUR has a significant familial component, and siblings and children of affected individuals are more likely to have reflux.
Secondary VUR develops later in life due to another condition that increases bladder pressure or otherwise disrupts the normal valve mechanism. Causes include bladder outlet obstruction (such as from posterior urethral valves in boys or, in adults, an enlarged prostate), neurogenic bladder (from spinal cord injury or other neurological conditions), and, occasionally, prior surgery or radiation.
VUR is graded on a five-point scale (Grade I through Grade V) based on how far the reflux extends and how much it dilates the ureter and collecting system. Grade I is the mildest (reflux into the ureter only, without dilation) and Grade V is the most severe (reflux with significant dilation and tortuosity of the ureter and marked distention of the renal pelvis and calyces). Higher grades of reflux are more likely to cause kidney damage and less likely to resolve on their own.
The clinical significance of VUR relates primarily to two mechanisms of kidney damage.
The first mechanism is infection. When reflux carries infected urine from the bladder up to the kidneys, it can cause pyelonephritis (kidney infection). Repeated episodes of pyelonephritis, particularly in young children whose kidneys are still developing, can lead to permanent kidney scarring. Areas of scarring typically appear as focal thinning or contour irregularity of the kidney with underlying calyceal changes on imaging.
The second mechanism is the effect of persistent high pressure from severe reflux, which can affect kidney development and function even without infection—particularly in severe congenital reflux with associated abnormalities of kidney development.
The imaging finding referred to as “vesicoureteral reflux sequelae”—which is what this page focuses on—typically refers to the long-term appearance of past reflux and its effects on the kidney, most often reflux nephropathy. The characteristic finding is one or more focal areas of thinning or scarring in the kidney, often with a corresponding indented outline and underlying blunted (dilated) calyces. Scars often affect the upper and lower poles of the kidney disproportionately because of the anatomy of the collecting system. In severe cases, the affected kidney may be smaller than normal (atrophic), and both kidneys may be affected in bilateral reflux. Related findings can include dilated ureters and, occasionally, evidence of prior surgical treatment of reflux (such as reimplanted ureters or endoscopic injection material).
In adults, most people with reflux sequelae have no active symptoms and normal or only mildly reduced kidney function. Some develop high blood pressure (particularly in younger adults or with more extensive scarring), protein in the urine, or, over time, more significant reduction in kidney function. Recurrent urinary tract infections may occur, though many adults with prior childhood reflux do not have significant infection problems. In pregnant patients, prior reflux nephropathy is associated with an increased risk of urinary tract infections during pregnancy, and, in some cases, an increased risk of pregnancy-related high blood pressure or preeclampsia.
In children with active reflux, the presentation is different. Many are identified during evaluation of a first or recurrent febrile urinary tract infection, or through screening after a sibling has been diagnosed. Some are identified prenatally when hydronephrosis is seen on ultrasound. Symptoms of active reflux typically relate to associated urinary tract infections rather than to reflux itself.
Diagnosis of established sequelae in adults is typically based on imaging showing the characteristic pattern of kidney scarring, focal atrophy, or reflux nephropathy. Kidney ultrasound can identify these findings, though more subtle scars may be missed. CT and MRI can also identify the changes. DMSA (dimercaptosuccinic acid) renal scan is particularly sensitive for detecting kidney scarring and is considered the gold standard for identifying reflux nephropathy in specific settings. Voiding cystourethrography (VCUG) is generally not repeated in adults with established sequelae unless there are ongoing symptoms suggesting active reflux (which is uncommon in adults who had childhood reflux).
In children, evaluation for active reflux typically includes VCUG (which involves catheterizing the bladder, filling it with contrast, and taking X-rays during voiding to demonstrate any reflux). Nuclear medicine cystography is an alternative that uses less radiation. Kidney ultrasound and DMSA scans provide information about associated findings and any scarring.
Blood tests including creatinine and estimated glomerular filtration rate (eGFR), and urine tests for protein and blood, are important in evaluating kidney function and monitoring for signs of injury. Blood pressure measurement is essential.
Important to Know
Management of vesicoureteral reflux sequelae in adults focuses primarily on long-term protection of kidney function, monitoring for complications, and management of any active issues. Care is typically coordinated by primary care clinicians and nephrologists (kidney specialists) or urologists, with involvement from other specialists as needed. Management of active reflux in children is coordinated by pediatric urologists, pediatric nephrologists, and pediatric infectious disease specialists.
For adults with established sequelae from prior reflux and no active problems, management focuses on protecting the kidneys from further injury and monitoring for complications. Blood pressure control is one of the most important aspects. High blood pressure is common in patients with reflux nephropathy, particularly with bilateral scarring, and can worsen kidney function over time. ACE inhibitors or angiotensin receptor blockers (ARBs) are often preferred because they both lower blood pressure and provide direct kidney protection, particularly when protein is present in the urine. Blood pressure targets are individualized.
Management of protein in the urine (proteinuria) is important because it is both a marker of kidney injury and a factor that can worsen kidney function. ACE inhibitors and ARBs are the primary treatments for proteinuria in reflux nephropathy, and newer options (such as SGLT2 inhibitors) may be considered in specific circumstances. Reduction in dietary sodium may also be helpful.
Avoidance of medications and substances that can harm the kidneys is important, particularly in patients with any degree of reduced kidney function. Nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen and naproxen) should generally be limited. Careful attention to medication dosing based on kidney function is important, and certain contrast agents used in imaging may require special consideration. Avoiding smoking and limiting alcohol also support kidney health.
Management of urinary tract infections is important. Symptomatic infections should be promptly evaluated and treated with appropriate antibiotics. In adults with a history of reflux nephropathy who develop recurrent urinary tract infections, further evaluation may be appropriate to identify contributing factors. Long-term preventive antibiotics are not routinely used in adults but may be considered in specific circumstances.
Management of other health conditions that affect the kidneys is essential. Diabetes, obesity, and cardiovascular risk factors should be addressed. A generally healthy diet, adequate hydration, and regular physical activity all support overall kidney and general health.
Periodic monitoring includes clinical assessment, blood pressure measurement, blood tests for kidney function, and urine tests for protein and blood. The frequency of monitoring is individualized based on the specific findings and other risk factors.
Care during pregnancy in patients with reflux nephropathy requires special attention. Kidney function, blood pressure, and protein in the urine should be monitored more closely, and urinary tract infections should be promptly evaluated and treated. In selected patients, preventive antibiotics during pregnancy may be considered, particularly in those with recurrent infections. Coordination with obstetrics, nephrology, and, when appropriate, maternal-fetal medicine is important.
For active reflux in children, management is guided by the grade of reflux, the frequency and severity of infections, kidney function, and other factors. Options include observation with monitoring, low-dose preventive antibiotics (which is common in some grades of reflux and in specific settings, particularly in younger children with a history of febrile infections), endoscopic injection of a bulking agent at the ureteral opening to prevent reflux (a minimally invasive procedure), and surgical repair (ureteral reimplantation) for higher-grade or refractory cases. The role of preventive antibiotics has been an area of active research and evolving guidelines. Coordination with pediatric urology and, when needed, pediatric nephrology is important.
Family screening is considered in children with newly diagnosed reflux, particularly in specific settings. Siblings of affected children have an increased likelihood of having reflux, though screening protocols vary. Prenatal identification of urinary tract abnormalities may also prompt postnatal evaluation.
For patients with kidney function that has significantly declined, care may involve nephrology follow-up, management of complications of chronic kidney disease (anemia, bone and mineral disorders, electrolyte disturbances), cardiovascular risk reduction, and, in advanced stages, preparation for kidney replacement therapy (dialysis or transplant) when needed.
Care is typically coordinated by primary care clinicians and, when needed, nephrologists, urologists, and, in children, pediatric specialists. Imaging and laboratory findings are interpreted alongside the patient’s symptoms, examination, history, and broader clinical context rather than in isolation.
Patient education plays an important role. Understanding the history of reflux and the meaning of imaging findings, the importance of long-term monitoring and protective measures, the rationale for medication choices and lifestyle recommendations, warning signs of kidney or urinary tract problems, and, when relevant, the implications for family members and pregnancy all contribute to better outcomes.
Red flag symptoms include severe flank or back pain, high fever with chills (particularly with signs of severe urinary tract infection or possible kidney infection), significant decrease in urine output, blood in the urine, severe swelling, severe hypertension, symptoms of severe electrolyte abnormalities (severe weakness, muscle cramps, irregular heartbeat), severe abdominal pain, or rapid clinical deterioration. These warrant prompt or urgent medical evaluation, as they may indicate acute infection, worsening kidney function, or other serious problems.