Reflux nephropathy: kidney scarring linked to urine reflux

Urine normally travels one way: from each kidney down a ureter to the bladder. Kidney Research UK describes vesico-ureteric reflux (VUR) as a condition in which urine travels back up the ureters towards the kidney, most commonly while the bladder is emptying. The ureter normally enters the bladder at an angle through a tunnel of muscle; in VUR it goes straight through the bladder wall, leaving an open entrance so that reflux occurs.

The charity explains that scars in the kidneys can arise from infections in infancy or because the kidney developed abnormally before birth, a condition called renal dysplasia, which is particularly associated with severe reflux. Whichever is the cause, the scarring is a form of kidney damage often called reflux nephropathy. It differs from the reflux itself: a person may have had reflux that resolved long ago but be left with scarred kidneys.

Because the scarring is permanent, the aims of care are to prevent new scars, to protect the remaining kidney function and to watch for blood pressure problems and protein in the urine over the years.

Kidney Research UK says VUR may be suspected if you or your child has frequent or severe UTIs. The symptoms listed are a burning or stinging sensation when passing urine, a sudden need to pass urine and passing urine more often, abdominal pain, foul-smelling urine and fever. In babies and young children symptoms are less specific and may be just a fever, prolonged jaundice, poor feeding or vomiting.

The charity also notes that reflux can be symptom-free and be found only after another family member is diagnosed, or during investigations for something else such as kidney stones. In adults, scarring is often noticed indirectly, for example through high blood pressure or protein in the urine on a routine test. The NHS says early kidney disease usually has no symptoms and may only be diagnosed when blood or urine tests are done for another reason.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 for a suspected kidney infection with features such as a very high temperature, shivering, pain in the lower tummy or the back under the ribs, blood in the pee, feeling or being sick, not having peed all day or being pregnant. It says to call 999 or go to A&E if you are confused, drowsy or have difficulty speaking, because a kidney infection can cause sepsis.

For children, the NHS notes that a child under 2 years may have only a high temperature, so unexplained fever in a baby should be assessed promptly. If someone in your family has reflux or kidney scarring, tell your GP, because that can change how infections and screening are handled.

Kidney Research UK describes the following investigations. An ultrasound scan looks for dilatation in the kidneys or ureters and whether the bladder is emptying fully, and can even be done before birth. Further tests are usually needed to make a firm diagnosis of reflux.

Kidney Research UK says that most children with VUR, especially the lower grades, will grow out of it, so management aims to prevent UTIs and ensure infections are diagnosed and treated promptly to avoid kidney damage. Preventive antibiotics have been shown to reduce the number of UTIs, especially with more severe grades of reflux. Practical measures include drinking plenty of fluids, emptying the bladder frequently, changing nappies often, wiping front to back and double voiding, in which you return to the toilet a few minutes later to empty the bladder again. Adults are advised to empty the bladder soon after sex.

If infections continue despite preventive antibiotics, the charity says referral to urologists for an anti-reflux procedure may be made. There are two main forms: an injection of material around the opening of the ureter, usually a day case, and a larger operation to re-implant the ureter into the bladder.

For the kidney scarring itself, Kidney Research UK says treatments may not be required for mild scarring, but high blood pressure or protein in the urine may need medicines such as ACE inhibitors and angiotensin receptor blockers. It advises that people with scarring avoid non-steroidal anti-inflammatory drugs such as ibuprofen, naproxen and diclofenac where possible, because they can reduce the blood supply to the kidneys, and take paracetamol for discomfort instead.

The long-term focus is regular monitoring: yearly blood pressure measurement, urine tests for protein and blood tests for kidney function. The NHS describes chronic kidney disease as a long-term condition in which the kidneys do not work as well as they should, diagnosed with blood and urine tests, and says that most people can control the condition with medicine and regular check-ups. NICE Clinical Knowledge Summaries list obstructive uropathy and nephrotoxic drugs among the causes of CKD.

Pregnancy deserves planning. Kidney Research UK notes that high blood pressure or protein in the urine can develop during pregnancy in someone with kidney scarring, so tell the antenatal team about it early. If you have a family history, the charity says babies of people with reflux have about a 20-25% chance of being born with it, and ultrasound can sometimes detect abnormalities before birth.

Prompt attention to UTIs matters throughout life. The NHS says UTIs and kidney infections are more likely if there is a kidney problem, and that you should see a GP if you keep getting UTIs.

On the NHS, children with reflux are looked after by paediatric nephrology or urology teams, and adults with scarring by their GP with referral to a kidney specialist when needed. A private kidney specialist or urologist can provide a second opinion or quicker imaging. The key point is continuity: someone should own the yearly blood pressure and urine checks, and your records of past scans, such as DMSA results, are worth keeping.