What Is Vesicoureteral Reflux?

Vesicoureteral reflux (VUR) refers to the reflux or backflow of urine from the bladder to the ureters.¹ The urinary system comprises the kidneys, ureters, bladder and urethra. It works as a filter to clear the toxins and waste products from the body. This waste is termed as urine. Urine passes through a pair of tubes called ureters and is stored in the urinary bladder. When the bladder gets full, we feel the urge to pee or urinate. During urination, the urine leaves the bladder through the urethra. This is the normal process of urine flow. However, in vesicoureteral reflux, the urine goes back up in the ureters from the bladder.  If left untreated, this abnormal flow can lead to infections and kidney damage.² 

Overview 

Vesicoureteral reflux (VUR), also called vesicoureteric reflux, is mostly diagnosed in newborns and children. It is mostly a congenital defect, which means it is present during birth, and it seems to get better with time. Around 1-3% of children have vesicoureteral reflux. 1 in 100 to 1 in 150 boys suffer from VUR. It is more common in girls. In some cases, it is hereditary in nature. 

Antenatal scans, which are scans during pregnancy, can sometimes reveal VUR. In such cases, diagnosis needs to be confirmed after the baby is born. 

Types of vesicoureteral reflux 

Vesicoureteral reflux is categorised into two types.³

• Primary vesicoureteral reflux: In primary VUR, the ureter does not implant into the bladder in a normal manner due to the incomplete formation of a valve. This causes the urine in the bladder to flow back into the ureter or kidneys. It mostly gets better as the child ages.
• Secondary vesicoureteral reflux: In secondary VR, there is a blockage in the urinary tract. An increase in pressure causes the urine to flow back into the ureter or kidneys. Sometimes, there might be some problems in the nerve, which might cause secondary VUR.

Grades of vesicoureteral reflux 

Vesicoureteral reflux is classified into five grades:³,⁴ 

• Grade 1: The urine goes back into the normal-sized ureter. 
• Grade 2: The urine goes back into the kidney's pelvis area through the normal-sized ureter.
• Grade 3: The ureters and kidney pelvis are mildly enlarged or dilated due to urine backup.
• Grade 4: The ureters and kidney pelvis are moderately enlarged due to excessive urine backup.
• Grade 5: The ureters and kidney pelvis are extremely enlarged due to excessive urine backup.

Causes of vesicoureteral reflux 

There are two causes of vesicoureteral reflux: Incomplete formation of the valve between bladder and ureter leads to primary VUR. Whereas a blockage in the urinary tract leads to secondary VUR. 

Signs and symptoms of vesicoureteral reflux 

Vesicoureteral reflux does not always have symptoms. They can often cause Urinary Tract Infections (UTIs). Around 30-50% of children with UTI have VUR. Symptoms of UTI are¹,³,⁵ 

• Fever 
• Burning pain during urination 
• Lower abdominal pain 
• Back pain 
• Frequent urination 
• Bladder leakage 
• Urine smells bad 
• Lack of appetite 
• Irritated mood 

Untreated VUR can cause some additional symptoms as the child ages. It is caused by a condition called reflux nephropathy.

• Bed-wetting 
• Constipation 
• High blood pressure 
• Protein in urine

Diagnosis of vesicoureteral reflux 

Several diagnostic procedures are used to diagnose the presence of vesicoureteral reflux.²,³,⁴ 

• Blood tests: Blood tests are useful in diagnosing VUR. The presence of high levels of protein or creatinine signals VUR. They might also lead to kidney damage.
• Urine tests: Urine tests and cultures help in diagnosing VUR, kidney damage or infections. The presence of bacteria in urine can signal infections.
• Blood pressure monitoring:  Regular monitoring of a child’s blood pressure can help to prevent any kidney damage. 
• Ultrasound (USG):. Ultrasounds during pregnancy can indicate vesicoureteral reflux in some cases. In such infants, an ultrasound is done to confirm VUR diagnosis. 
• DMSA scan: Dimercapto Succinic Acid (DMSA) is a radiopharmaceutical injected in the child to check for renal scarring due to UTI.
• Direct Radionuclide Cystography (DRNC): It can also be called radionuclide histogram (RNC). In this, a radiopharmaceutical is injected into the child's bladder and images are acquired during filling up and after emptying the bladder. 
• Voiding Cystourethrogram (VCUG):  A radiological procedure involving X-rays. A special dye is injected through a catheter in the urethra. Images of the ureter and bladder before, during and after urination are acquired. This procedure is called voiding. An X-ray can detect the backward flow of urine. 

Management and treatment for vesicoureteral reflux 

There are various treatment options available depending on the age of the child and the severity of VUR or symptoms.¹,³,⁴

• Wait and watch: If your child has primary vesicoureteral reflux, the doctor might try a wait-and-watch approach. There is a chance that while growing, the issues in the urinary tract get resolved on their own. If your child is suffering from urinary tract infections, they might be prescribed antibiotics. But, the use of antibiotics is limited to prevent antibiotic resistance. 
• Medications: Doctors might prescribe some medications, such as Angiotensin-converting enzyme (ACE) inhibitors and Angiotensin receptor blockers (ARB), to prevent kidney damage due to high blood pressure.
• Endoscopic surgery:  A lighted tube (cystoscope) is inserted through the urethral orifice, and a bulking agent is injected. This helps the valve to close properly, which can resolve the reflux issues to some extent. The success rate varies depending on the condition of the patient.
• Open surgery: It requires anaesthesia administration and a hospital stay. The surgeon makes an incision in the lower abdomen to fix the ureteral valve. This process is called ureteral reimplant and is considered the gold standard of treatment for vesicoureteral reflux. 
• Robotic Assisted Laparoscopic Ureteral Reimplantation (RALUR): Also called minimally invasive surgery. It is similar to open surgery, but the incisions are quite small compared to open surgery. It is associated with less pain and short hospital stays. However, the disadvantages are the high cost of surgery and the need for skilled professionals.

Risk factors 

Some of the risk factors for vesicoureteral reflux are:¹,⁶

• Bladder and bowel dysfunction (BBD): Children with BBD experience frequent UTIs and vesicoureteral reflux. 
• Ethnicity: White children are at greater risk of VUR.
• Genetics: A child who has a family history of VUR is susceptible to it.
• Gender: VUR is mostly diagnosed in girls. 
• Age: Children under the age of 2 years are at greater risk of VUR compared to older children.
• Body defects: Children born with neural tube defects such as spina bifida or urinary tract abnormalities such as ureterocele, posterior urethral valves or ureteral duplication are susceptible to VUR.

Complications 

Vesicoureteral reflux causes the backflow of urine from the bladder to the ureters and, sometimes, to the kidneys. Some of the complications posed by reflux are:¹,⁷ 

• Renal scarring: Reflux of urine can lead to urinary tract infections. Frequent UTIs result in scarring of the kidney tissue, known as renal scarring. 
• High blood pressure: Kidneys filter the waste and toxins from the body. So, damage to the kidneys might increase the waste build-up in the body, thus increasing blood pressure.
• Kidney failure: Untreated VUR might result in kidney damage, which may result in kidney failure. 

FAQs

How can I prevent vesicoureteral reflux? 

There are no proven ways to prevent VUR. But consuming sufficient fluids, regular urination, and regularly changing your child’s diaper can help prevent the chances of VUR.

How common is vesicoureteral reflux? 

Around 1-3% of children are diagnosed with vesicoureteral reflux. 

When should I see a doctor? 

If you suspect a urinary tract infection, then please contact your GP. They might refer you to paediatric nephrology or paediatric urology department to get vesicoureteral reflux treatment if detected.

Summary 

Vesicoureteral reflux is the backflow of urine from the bladder to the ureters and kidneys. This leads to urinary tract infections. If VUR is left untreated, it might lead to renal scarring, high blood pressure and renal failure. It is sometimes detected antenatally, and confirmation is done after birth. Diagnostic procedures include blood tests, urine tests, urine cultures, ultrasounds, DMSA scans, DRNC and VCUG. Treatment depends on the severity of symptoms and condition of the patient. Medications, a wait-a-watch approach, endoscopic surgery, open surgery or robotic-assisted surgery can be done to treat the disorder. 

VUR isn't painful or life-threatening, so there is no need to panic. Drinking lots of water, regularly changing diapers and consuming a healthy diet may help in preventing this disorder.