Nephrology · KIMS Secunderabad
Reflux Nephropathy — Kidney Scarring from Childhood Reflux and Its Lifelong Consequences
Reflux nephropathy is the kidney damage — focal cortical scarring — that results from urinary tract infections occurring in the setting of vesicoureteral reflux (VUR). When infected urine refluxes from the bladder into the kidney during voiding, bacteria and inflammatory mediators are delivered directly to the renal parenchyma, causing acute pyelonephritis and, if this is repeated over years, progressive focal scarring of the renal cortex. Each scar represents a permanently lost nephron — replaced by fibrotic tissue that contributes nothing to kidney function.
Reflux nephropathy is one of the most important preventable causes of CKD in young adults in India. It begins in childhood — often in infants with undetected VUR who suffer recurrent urinary tract infections — and presents in adulthood as hypertension, proteinuria, or impaired kidney function that appears out of nowhere in a young person with no obvious kidney disease. The prevention window is childhood; the management window — once established — is damage limitation.
How reflux nephropathy develops
Not all VUR causes nephropathy — the key is infected reflux. Sterile urine refluxing into the kidney causes less damage than infected urine, though high-pressure sterile reflux can cause some parenchymal injury. The destructive cycle in reflux nephropathy:
VUR allows infected bladder urine to enter the kidney during voiding — intra-renal reflux carries bacteria directly into the collecting ducts and papillary tubules.
Acute pyelonephritis results — the renal parenchyma around the infected tubule is inflamed. In infants and young children, the parenchyma is more susceptible to scarring than in older children and adults.
Scar forms at the site of infection — within 4 to 6 weeks of a pyelonephritis episode, a focal cortical scar can be detected on DMSA scan as an area of reduced uptake.
Repeated pyelonephritis adds more scars — cumulative scarring reduces the functional renal mass progressively.
Focal scarring triggers glomerular hyperfiltration in the adjacent non-scarred nephrons — the compensatory hyperfiltration gradually damages the remaining glomeruli (FSGS-pattern sclerosis), causing proteinuria and accelerating CKD.
Clinical presentation in adults with established reflux nephropathy
Hypertension — often severe, onset in 20s to 30s
The scarred kidney produces excess renin from ischaemic tissue at the scar margins. Hypertension from reflux nephropathy is typically renovascular in origin and may be difficult to control.
Proteinuria — from FSGS-pattern hyperfiltration
The non-scarred nephrons hyperfiltrate to compensate for lost scarred tissue. This hyperfiltration damages the glomerular filtration barrier, causing progressive proteinuria — a marker of accelerating CKD.
Impaired eGFR — proportional to the extent of scarring
Small bilateral scarred kidneys with significantly reduced total functional mass. The eGFR at presentation depends on how many scars accumulated and how much kidney tissue remains.
Recurrent UTIs — in women with VUR into adult life
Residual low-grade VUR in adult women with reflux nephropathy increases susceptibility to ascending pyelonephritis — each episode risks adding further scarring.
Preeclampsia risk — in pregnancy
Women with reflux nephropathy have a higher risk of preeclampsia and worsening kidney function during pregnancy. Pre-conception nephrology review at KIMS is important.
Incidental finding on imaging
Small irregular kidneys with cortical scars detected on ultrasound or CT performed for an unrelated reason.
Diagnosis
DMSA (dimercaptosuccinic acid) scan
The gold standard for detecting cortical scars. Areas of reduced uptake on DMSA correspond to scarred, non-functioning cortex. DMSA also provides split kidney function — the relative contribution of each kidney to total GFR. An adult presenting with hypertension and asymmetric kidneys on ultrasound should have a DMSA scan to assess whether unilateral reflux nephropathy is driving renovascular hypertension from the smaller scarred kidney.
Renal ultrasound
Small echogenic kidneys with cortical thinning and irregular outlines in established reflux nephropathy. Asymmetry between kidneys strongly suggests unilateral reflux nephropathy.
VCUG (voiding cystourethrogram)
Identifies ongoing VUR in adults with recurrent UTIs and suspected reflux nephropathy. VUR may have resolved in many adults — but confirming whether ongoing reflux is contributing to recurrent pyelonephritis determines whether ureteric reimplantation is still indicated.
Urine ACR and eGFR
Quantify proteinuria and kidney function. Serial measurements track progression.
Blood pressure measurement
Hypertension is present in 10 to 20% of adults with bilateral reflux nephropathy and should be treated aggressively.
Management
Prevent further pyelonephritis
In adults with ongoing VUR and recurrent UTIs — antibiotic prophylaxis, ureteric reimplantation for persistent high-grade VUR, treatment of bladder dysfunction contributing to elevated voiding pressures.
Manage hypertension and proteinuria
ACE inhibitors or ARBs — reduce both blood pressure and proteinuria (antiproteinuric effect independent of blood pressure). Target BP below 130/80 mmHg, or below 125/75 in those with significant proteinuria. SGLT2 inhibitors for additional kidney protection where eligible.
Nephrectomy for unilateral reflux nephropathy with renovascular hypertension
In selected patients — a small, non-functioning (below 10% differential function on DMSA), hypertension-driving kidney from unilateral reflux nephropathy may be removed. Nephrectomy can be curative for hypertension when the scarred kidney is driving renin-mediated hypertension and the contralateral kidney function is adequate.
Book a Reflux Nephropathy Assessment at KIMS
Frequently Asked Questions — Reflux Nephropathy
The established scarring of reflux nephropathy cannot be reversed — cortical scars represent permanently destroyed nephrons replaced by fibrotic tissue. However, further scar formation can be prevented by treating the underlying VUR (to eliminate infected reflux) and by preventing recurrent pyelonephritis. The proteinuria and CKD progression from reflux nephropathy can be significantly slowed with ACE inhibitors or ARBs. In selected patients with unilateral reflux nephropathy where the scarred kidney is driving renin-mediated hypertension, nephrectomy can cure or significantly improve blood pressure control.
Most adults with reflux nephropathy were never diagnosed with VUR as children — either because investigation was not done after childhood UTIs, or because VUR resolved spontaneously but left scars. Clues that suggest a history of reflux nephropathy: hypertension in the 20s or 30s without other obvious cause, asymmetric kidneys on imaging (one kidney significantly smaller than the other), irregular cortical outlines or cortical thinning on renal ultrasound, a history of frequent UTIs or kidney infections in childhood. A DMSA scan and renal ultrasound at KIMS establishes whether cortical scarring is present and quantifies the extent.
Reflux nephropathy can affect one kidney (unilateral) or both (bilateral), depending on whether VUR was unilateral or bilateral and whether both kidneys suffered pyelonephritis episodes. Unilateral reflux nephropathy typically presents with asymmetric kidney size — the scarred kidney is smaller — and renovascular hypertension from the ischaemic scarred kidney. Bilateral reflux nephropathy presents with more symmetrically reduced kidney function, hypertension, and proteinuria. Bilateral reflux nephropathy carries a higher risk of progression to ESRD than unilateral.
Yes — reflux nephropathy accounts for 5 to 15% of ESRD in adults below 40 worldwide, and India's high prevalence of childhood UTIs — combined with delayed investigation and under-treatment of VUR — makes reflux nephropathy a significant contributor to young-adult ESRD in the Indian population. It is a largely preventable cause of ESRD: identifying VUR in children after febrile UTIs, treating appropriately, and preventing recurrent pyelonephritis with antibiotic prophylaxis or surgery protects the kidneys from cumulative scarring. Prevention starts in childhood — the adult nephropathy clinic at KIMS treats the consequences of what was missed in childhood.
KIMS Secunderabad — Dr. E. Ravi (Senior Consultant Nephrologist), DMSA scan for cortical scar assessment, split renal function, VCUG for ongoing VUR evaluation, ACE inhibitor and ARB protocol, SGLT2 inhibitor for CKD progression, urology coordination for VUR management and nephrectomy for unilateral reflux nephropathy with renovascular hypertension. NABH and NABL accredited. Call 040-4488-5000.