Ureteric Reflux in Adults: Symptoms & Diagnosis

Ureteric reflux in adults is one of those diagnoses most people assume can’t apply to them. Reflux — urine flowing backward from the bladder up toward the kidney instead of draining one way — is framed as a childhood condition that’s outgrown by school age. Often it is. But it doesn’t always vanish, and in some adults it was never caught at all. I usually meet it wearing a disguise: a man in his 30s or 40s with kidney infections that keep returning no matter how many antibiotic courses he finishes. For the full picture of how the urinary tract is meant to drain, see our complete Kidney Health Hub. The reason reflux matters isn’t the infection itself — it’s what years of pressure and bacteria do to the kidney behind it. This article explains what adult reflux is, how it’s diagnosed, and when it actually needs treatment versus watchful monitoring.

What Ureteric Reflux Actually Is

Your ureters are the two muscular tubes that carry urine from the kidneys down to the bladder. Where each ureter enters the bladder, it doesn’t just open through a hole — it tunnels at an angle through the thick muscular bladder wall for about a centimeter. That oblique tunnel works as a one-way flap valve. When the bladder fills and squeezes to empty, the rising pressure presses the tunnel shut, so urine is forced out through the urethra and not back up toward the kidney.

Vesicoureteral reflux happens when that valve fails. If the tunnel is too short or too straight, bladder pressure can no longer pinch it closed, and a jet of urine tracks backward up the ureter — sometimes all the way to the kidney. In children this is usually a congenital problem with how the junction formed. In adults, it’s either a milder congenital reflux that simply never resolved, or it’s secondary reflux: the valve is overwhelmed by high bladder pressures from another problem, such as a neurogenic bladder, severe bladder outlet obstruction, or prior pelvic surgery.

That distinction matters more in adults than in kids. Primary reflux is a plumbing defect at the junction. Secondary reflux is a pressure problem upstream — and if you only fix the valve without fixing the pressure, the reflux comes straight back.

The Symptoms That Bring Adults to a Urologist

Reflux itself causes no sensation. You cannot feel urine moving the wrong way. What you feel is the consequence — and in adults that is almost always infection reaching the kidney. The pattern I watch for is repeated episodes of pyelonephritis (a kidney infection): fever, chills, and a deep ache or tenderness in the flank, the area just below the back of the ribs, rather than the low burning of a simple bladder infection.

Each symptom points to a mechanism. The flank pain reflects the kidney itself becoming inflamed, because reflux delivered bacteria straight up to it. The high fever signals the infection has reached kidney tissue rather than staying in the bladder. And the sheer recurrence — three, four, five infections in a year despite correct treatment — is the clue that something structural is letting bacteria climb back up each time. When kidney infections keep returning in a man, reflux belongs on the list of causes to rule out, which is exactly why a structured workup matters. Our guide to the diagnostic workup for recurrent urinary infections in men walks through that process in detail.

Some adults have no infections at all and are picked up by accident — a dilated ureter or kidney scarring spotted on a scan done for another reason, or high blood pressure traced back to old kidney damage. A smaller group presents with vague, long-standing flank discomfort that worsens when the bladder is full.

How Ureteric Reflux Is Diagnosed in Adults

Diagnosis follows a logical order, moving from cheap and non-invasive toward the definitive test only when the picture demands it. The first step is confirming and characterizing the infections with a urine culture, and checking kidney function with a blood creatinine and eGFR (estimated glomerular filtration rate, a measure of how well the kidneys filter). If you want to understand what those numbers mean, our CKD stage calculator shows how eGFR maps to kidney function stages.

Next comes imaging. A renal and bladder ultrasound is the usual starting scan because it’s harmless and shows obvious problems — a dilated ureter, a swollen kidney (hydronephrosis), or thinned, scarred kidney tissue. The catch is that ultrasound can look completely normal in low-grade reflux, because the urine refluxes only intermittently and the scan is a single snapshot. A normal ultrasound does not rule reflux out.

The definitive test is the voiding cystourethrogram (VCUG). A thin catheter fills the bladder with contrast dye, then X-ray images are taken while you urinate. If contrast tracks backward up a ureter, reflux is confirmed and graded on a standard scale from Grade I (urine reaches only the lower ureter) to Grade V (severe reflux with a grossly dilated, tortuous ureter and a swollen kidney). That grade drives every treatment decision that follows.

In selected adults a nuclear medicine scan (a DMSA renal scan) is added to map exactly where the kidney has been scarred and how much working tissue remains. This matters most when deciding whether a kidney is worth protecting surgically or has already been damaged beyond rescue.

What Reflux Does to the Kidney Over Time

The condition that gives reflux its importance is reflux nephropathy — the permanent scarring of kidney tissue caused by the combination of backward pressure and recurrent infection. Each episode of infected urine reaching the kidney triggers inflammation, and inflammation that heals leaves a scar. Over years, those focal scars add up, the working filtering tissue thins, and the kidney’s overall function drifts downward.

This is why reflux is not just an infection nuisance. Reflux nephropathy is one of the recognized causes of chronic kidney disease, and in some people it surfaces decades later as unexplained high blood pressure or protein leaking into the urine. If a urine test ever shows protein, that finding deserves its own explanation — our article on what protein in the urine means covers why it can signal early kidney strain.

The damage is cumulative and largely silent, which is the frustrating part. A kidney can lose a meaningful share of its function before any blood test flags it, because the healthy kidney compensates. That’s the mechanical argument for taking adult reflux seriously even when an individual infection feels minor: you are not just treating today’s fever, you are trying to stop the next scar.

Treatment: When Reflux Needs Action and When It Doesn’t

Treatment is matched to the grade of reflux, the state of the kidneys, and whether infections are breaking through. The goal is always the same: protect kidney function and stop infected urine from reaching the kidney. How aggressively you pursue that depends on the risk.

Conservative management suits low-grade reflux (roughly Grade I–II) with normal kidneys and infrequent infections. This means treating infections promptly, staying well hydrated to keep urine flowing and dilute, emptying the bladder fully and on a regular schedule, and monitoring kidney function with periodic eGFR checks. For adults whose reflux is secondary to a pressure problem, fixing that upstream cause — relieving outlet obstruction, managing a neurogenic bladder — often resolves the reflux without ever touching the valve.

Surgical correction is considered for high-grade reflux (Grade III–V), progressive kidney scarring, or breakthrough kidney infections despite good conservative care. Two main options exist. An endoscopic bulking injection places a small amount of material beneath the ureteric opening through a cystoscope, lifting it into a competent valve — a day procedure with quick recovery, better suited to lower grades. Ureteric reimplantation is the more durable repair: the surgeon detaches the ureter and re-tunnels it through the bladder wall at a proper oblique angle to rebuild the one-way valve, with higher success rates for severe reflux at the cost of a bigger operation.

If you suspect reflux is behind your infections, the concrete next step is to ask your urologist directly: “Given how often these kidney infections keep coming back, should I have a VCUG to check for reflux?” Bring a list of every infection with rough dates and which antibiotic was used. If a scan shows scarring or your eGFR has dropped, ask whether a DMSA scan is warranted to map the damage before deciding on treatment — and request a repeat eGFR within three to six months to track whether function is stable.

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Dr. Muhammad Khalid

MBBS · FCPS (Urology) · MCPS (Gen. Surgery) · CHPE · CRSM · IMC #539472

Specialist urologist with 11+ years of clinical experience across tertiary teaching hospitals. Trained at Lady Reading Hospital and Khyber Teaching Hospital, Peshawar. Author of 5 peer-reviewed international publications in Cureus, WJSA, and AJBS. Procedural expertise: URS, PCNL, RIRS, TURP, TURBT, and major open urological surgery. Full profile →

This article is for educational purposes only and does not constitute medical advice. Always consult your physician or urologist for diagnosis and treatment decisions specific to your condition.