Vesicoureteral reflux (VUR)
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Vesicoureteral reflux (VUR) is a medical condition characterized by the backward flow of urine from the bladder into the ureters and sometimes the kidneys. Normally, urine flows from the kidneys down the ureters and is stored in the bladder.
Vesicoureteral reflux commonly occurs in newborns, infants, and children under the age of two, although it can also affect older children and, rarely, adults. This condition poses an increased risk of urinary tract infections, which, if left untreated, can lead to kidney damage. It is worth noting that VUR is more prevalent in girls than in boys. The grading system for VUR consists of five grades, ranging from one to five, with five being the most severe form. The grades are determined based on the extent of urine reflux into the urinary tract and the width of the ureter(s).
- Grade I: Urine flows backward into a normally sized ureter.
- Grade II: Urine refluxes into the kidney’s pelvis area through a normal–sized ureter. The kidney pelvis and calyces, which collect and direct urine, remain unchanged in size.
- Grade III: The ureter(s), kidney pelvis, and calyces become mildly to moderately enlarged due to urine backup.
- Grade IV: The ureter(s) become moderately dilated and curved, and the kidney pelvis and calyces also display moderate dilation due to excessive urine accumulation.
- Grade V: The ureter(s) become extremely distorted and enlarged. The kidney pelvis and calyces exhibit significant enlargement caused by an excessive amount of retained urine.
While some children may eventually outgrow primary vesicoureteral reflux, it is crucial to promptly address the condition to prevent kidney damage. Treatment options for VUR include medication and surgery, both aimed at safeguarding the health of the kidneys.
Symptoms
Vesicoureteral reflux (VUR) often manifests without any noticeable symptoms in children. However, when symptoms do arise, the most common indicator is a urinary tract infection (UTI), which is frequently associated with VUR. It is estimated that around 30% to 50% of children diagnosed with UTI also have VUR. When VUR is present, it can create a conducive environment for bacterial growth in the urinary tract, leading to bladder and kidney infections.
Some common signs and symptoms of VUR and its related complications include:
- Persistent and intense urge to urinate.
- Burning sensation during urination.
- Frequent need to pass small amounts of urine.
- Fever.
- Pain in the side (flank) or abdomen.
- Cloudy and foul–smelling urine.
Diagnosing a urinary tract infection (UTI) in children can be challenging as they often exhibit nonspecific signs and symptoms. Infants with a UTI may also display the following indicators:
- Unexplained fever
- Decreased appetite
- Irritability
As children progress in age without receiving treatment for vesicoureteral reflux, a condition characterized by the backward flow of urine from the bladder to the kidneys, several complications can arise. These include bed–wetting, constipation or loss of bowel control, high blood pressure, and the presence of protein in the urine. Moreover, an additional indication of vesicoureteral reflux, detectable before birth through a sonogram, is the enlargement of the kidneys or the structures responsible for urine collection, known as hydronephrosis, which results from the accumulation of urine that flows back into the kidneys.
Causes
The urinary system comprises the kidneys, ureters, bladder, and urethra, all working together to eliminate waste products through urine. The kidneys filter waste from the blood and produce urine, which is then carried by the ureters to the bladder for storage. When the bladder is full, urine is released from the body through the urethra during the process of urination.
Vesicoureteral reflux can occur in two forms: primary and secondary.
- Primary vesicoureteral reflux: This type is more common and is present in children from birth. It is caused by a defect in the valve that normally prevents urine from flowing backward from the bladder into the ureters. Over time, as a child grows, the lengthening and straightening of the ureters may improve the valve function and correct the reflux. Primary vesicoureteral reflux often runs in families, suggesting a genetic component, although the exact cause of the defect is unknown.
- Secondary vesicoureteral reflux: The primary cause of secondary VUR is usually a blockage or narrowing in the bladder neck or urethra, leading to the backup of urine into the urinary tract instead of its proper exit through the urethra. Another contributing factor can be impaired nerve function in the bladder, which affects its ability to contract and relax normally, resulting in uncoordinated urine release. Secondary VUR is more commonly associated with bilateral reflux (affecting both sides) compared to unilateral reflux (affecting one side). In adults, vesicoureteral reflux is often associated with conditions such as benign prostate hypertrophy, neurogenic bladder, or previous surgeries near the ureters.
Risk factors
The follow factors increase the risk in developing vesicoureteral reflux:
- Family history: Primary vesicoureteral reflux often has a familial predisposition, with a family history of the disorder. Children are more likely to be affected if their parents already have the condition. Given the increased risk for siblings of affected children, healthcare providers may recommend screening for primary vesicoureteral reflux in siblings.
- Age: Older children are less likely to experience vesicoureteral reflux than infants and young children up to age 2.
- Sex. In general, females are more prone to experiencing this condition compared to males. However, there is an exception when it comes to vesicoureteral reflux present at birth, as it is more frequently observed in boys.
- Race: Vesicoureteral reflux appears to be more common in white children.
- Bladder and bowel dysfunction: Recurrent urinary tract infections and holding of urine and stools in children with bladder and bower dysfunction can cause vesicoureteral reflux.
Diagnosis
The most commonly used imaging tests for diagnosing vesicoureteral reflux (VUR) are as follows:
- Voiding cystourethrogram (VCUG): This is an x–ray image of the bladder and urethra taken before, during, and after urination. A small catheter is inserted into the urethra to fill the bladder with a special dye visible on x–rays. VCUG helps determine if urine is flowing backward from the bladder into the ureters. It can be done in a healthcare provider’s office, outpatient center, or hospital. While anesthesia is not usually required, sedation may be used for some children.
- Radionuclide cystogram (RNC): RNC is a nuclear scan involving the introduction of radioactive material into the bladder. A scanner detects the radioactive material during urination or after the bladder is emptied. This procedure is typically performed by a specially trained technician in a healthcare provider’s office, outpatient center, or hospital. The images are then interpreted by a radiologist. Anesthesia is generally not necessary, but sedation might be used for certain children. RNC is more sensitive than VCUG but provides less detailed information about the bladder’s anatomy.
- Dimercaptosuccinic acid (DMSA) scan: This imaging test helps identify any kidney scars resulting from a urinary tract infection (UTI) affecting the kidney. It is usually recommended when a kidney ultrasound shows abnormalities.
- Ultrasound: This painless and safe imaging technique uses sound waves to produce images of the entire urinary tract, including the kidneys and bladder. However, it does not provide detailed information about the grade of VUR. Ultrasound can be performed in a healthcare provider’s office, outpatient center, or hospital, and anesthesia is typically not required. It may be used before a VCUG or RNC if you or your healthcare provider wish to avoid exposure to x–ray radiation or radioactive material. It is often used in the following situations:
- Infants diagnosed during pregnancy (while they’re still in the uterus) with urine blockage affecting the kidneys.
- Children under the age of five who have a urinary tract infection (UTI).
- Children with a UTI and fever, known as febrile UTI, regardless of their age.
- Males with a UTI who are not sexually active, regardless of their age or presence of fever.
- Children with a family history of VUR, including those with an affected sibling.
- Children who are five years of age or older and have a UTI.
If your child has been diagnosed with vesicoureteral reflux (VUR), the following tests should be conducted:
- Blood pressure checks: Children with kidney problems are at a higher risk of developing high blood pressure. Regular monitoring is necessary to identify any abnormalities.
- Blood tests: These tests measure the levels of protein and creatinine in the blood. High protein levels or elevated creatinine levels indicate kidney damage.
- Urine tests and culture: Urine tests are performed to detect the presence of protein, which is a sign of kidney damage, and to identify any bacteria, which may indicate an infection.
Treatment
The treatment choices for vesicoureteral reflux are determined by the extent of the condition. If a child has a mild case of primary vesicoureteral reflux, they may eventually overcome the disorder without intervention. In such instances, a doctor might advise a watchful waiting approach.
In cases where vesicoureteral reflux is more severe, there are various treatment options available, including:
Medication
Medications play a crucial role in the treatment of vesicoureteral reflux. When it comes to urinary tract infections (UTIs), prompt administration of antibiotics is necessary to prevent the infection from spreading to the kidneys. Additionally, doctors may prescribe lower doses of antibiotics as a preventive measure against UTIs. During medication treatment, it is important to closely monitor the child with regular phvysical exams and urine tests to detect any breakthrough infections. Periodic radiographic scans of the bladder and kidneys may also be conducted to assess whether the child has outgrown vesicoureteral reflux.
Surgery
Surgery for vesicoureteral reflux aims to correct the defect in the valve between the bladder and the affected ureter, which causes urine to flow backward. There are different methods of surgical repair available:
- Open surgery: This procedure is performed under general anesthesia and involves making an incision in the lower abdomen. The surgeon accesses the valve and repairs the problem. After the surgery, a catheter is usually left in place to drain the bladder, and the child may need to stay in the hospital for a few days. In most cases, vesicoureteral reflux resolves on its own without further intervention, although it may persist in a small number of children.
- Robotic–assisted laparoscopic surgery: Similar to open surgery, this technique also involves repairing the valve between the ureter and the bladder. However, it is performed using small incisions and with the assistance of a robotic system. The advantages of this approach include smaller incisions and potentially fewer bladder spasms compared to open surgery. However, preliminary findings suggest that robotic–assisted laparoscopic surgery may have a lower success rate than open surgery. It also tends to have a longer operating time but results in a shorter hospital stay.
- Endoscopic surgery: This minimally invasive procedure involves the insertion of a cystoscope, a lighted tube, through the urethra to visualize the inside of the bladder. The doctor then injects a bulking agent around the opening of the affected ureter to strengthen the valve’s ability to close properly. Endoscopic surgery carries fewer risks compared to open surgery and can often be performed as outpatient surgery. However, it may not be as effective in treating vesicoureteral reflux. General anesthesia is required for this procedure.
