After the patient's bladder is filled with a liquid called contrast material, an X-ray machine sends beams of radiation through the abdomen and pelvis, and images are recorded on special film or a computer. These images help doctors see problems in parts of the urinary system, including the bladder, urethra (the tube connecting the bladder with the outside of the body), and the ureters (the tubes connecting the kidneys to the bladder).
A radiologist takes the X-rays using a technique called fluoroscopy. While the contrast material fills your child's bladder, and then while your child empties the bladder, the radiologist watches an onscreen X-ray video of the liquid moving through the urinary system and a series of X-ray films is recorded.
In general, X-rays are very safe. Although there is some risk to the body with any exposure to radiation, the amount used in a VCUG is small and not considered dangerous. It's important to know that Nemours radiologists use the minimum amount of radiation required to perform the study properly.
What does a VCUG show?
A VCUG can show whether the urine is moving in the right direction. Normally, urine flows from the kidneys down to the bladder through the ureters. When urine goes back up toward the kidneys, it's called vesicoureteral reflux (VUR), which a VCUG can detect. Sometimes VUR only occurs while urinating (voiding), which is why the VCUG includes taking X-ray images while the bladder is being emptied.
At times, fear, anxiety, and developmental stage of a child contribute to his or her ability to cooperate with medical procedures. Pediatric procedural sedation can be used to decrease discomfort and anxiety for your child.
Sedation is available for VCUG and a separate sedation appointment would be needed to be scheduled prior to the study.
Providing sedation means a child is given medicine to make the child more relaxed. When a child is sedated, he or she may better tolerate a medical procedure and will probably not remember it.
The sedation team aims for mild to moderate sedation, meaning that your child will be relaxed, but awake enough to answer questions and to sense a full bladder. Typical sedatives for this procedure include midazolam (Versed), given orally or as a nasal spray, or nitrous oxide (“laughing gas”) given with a mask. This procedure takes about 10 minutes for catheter placement and bladder filling, and another few minutes for the child to urinate.
Recurrent Urinary Tract Infections and Related Conditions
Urinary tract infections (UTIs) are common in kids, especially girls and uncircumcised boys. In fact, by age 5, about 8% of girls and 1%–2% of boys have had at least one UTI.
UTIs happen when the kidneys, ureters, bladder, or urethra become infected. Symptoms of a UTI can include:
pain when urinating
changes in frequency of urination
changes in appearance or smell of urine
loss of appetite
lower abdominal pain
lower back pain or discomfort
UTIs also can cause kids to wet their pants or the bed, even if they haven't had these problems before. Infants and very young children may only show nonspecific signs, such as fever, vomiting, or decreased appetite or activity.
Some kids get UTIs again and again — these are called recurrent UTIs. If not treated, recurrent UTIs can cause kidney damage, especially in kids younger than 6. So it's important to know how to recognize the signs of these infections and get help for your child.
Types of UTIs
Common types of UTIs include:
cystitis: this bladder infection is the most common type of UTI. Cystitis occurs when bacteria move up the urethra (the tube-like structure that allows urine to exit the body from the bladder) and into the bladder
urethritis: when bacteria infect the urethra
pyelonephritis: a kidney infection caused by infected urine flowing backward from the bladder into the kidneys or an infection in the bloodstream reaching the kidneys
Recurrent UTIs sometimes happen along with other conditions, such as:
vesicoureteral reflux (VUR), which is found in 30%–50% of kids diagnosed with a UTI and is a congenital (present at birth) condition in which urine flows backward from the bladder to the ureters. Ureters are thin, tube-like structures that carry pee from the kidney to the bladder. Sometimes the pee backs up to the kidneys and if it is infected with bacteria, can lead to pyelonephritis.
hydronephrosis, which is an enlargement of one or both kidneys due to backup or blockage of urine flow and is usually caused by severe VUR or a blocked ureter. Kids with hydronephrosis are sometimes at risk of recurrent UTIs and may need to take daily low doses of antibiotics to prevent UTIs until the condition producing hydronephrosis gets better or is fixed through surgery.
But not all cases of recurrent UTIs can be traced back to these body structure-related abnormalities. For example, dysfunctional voiding — when a child doesn't relax the muscles properly while urinating — is a common cause of UTIs. Infrequent urination (not peeing often enough) also can also increase a child's risk for recurrent infections. Both dysfunctional voiding and infrequent urination can be associated with constipation.
Unrelated conditions that harm the body's natural defenses, such as diseases of the immune system, also can lead to recurrent UTIs, although this is rare. In addition, use of a nonsterile urinary catheter can introduce bacteria into the urinary tract and cause an infection.
Although UTIs can be treated with antibiotics, it's important for a doctor to rule out any underlying abnormalities in the urinary system when UTIs happen repeatedly. Kids with recurrent infections should see a pediatric urologist to see what is causing the infections.
Some abnormalities can be found even before birth. Hydronephrosis that develops before birth can be detected in a fetus by ultrasound as early as 16 weeks of gestation. In rare cases, doctors may consider neonatal surgery (performing surgery on an unborn baby) if hydronephrosis affects both kidneys and poses a risk to the developing fetus. Most of the time, though, doctors wait until after birth to treat the condition, because almost half of all cases diagnosed prenatally disappear by the time a baby is born.
Once a baby suspected to have hydronephrosis or another urinary system abnormality is born, the baby's blood pressure will be monitored carefully, because some kidney abnormalities can cause high blood pressure. An ultrasound may be used again to get a closer look at the bladder and kidneys. If the condition appears to be affecting both kidneys, doctors usually will order blood tests to measure kidney function.
If an abnormality of the urinary tract is suspected, doctors might order tests to make an accurate diagnosis, including:
Ultrasound Using high-frequency sound waves to "echo," or bounce, off the body and create a picture of it, an ultrasound can detect some abnormalities in the kidneys, ureters, and bladder. It can also measure the size and shape of the kidneys.
When an ultrasound points to VUR or hydronephrosis, a renal scan or voiding cystourethrogram (VCUG) might give doctors a better idea of what's going on.
Renal scan (nuclear scan) Radioactive material is injected into a vein and followed through the urinary tract. The material can show the shape of the kidneys, how well they function, if there is damaged kidney tissue, and the course of the urine. A small amount of radiation is received during the test and leaves the body in the urine.
Voiding cystourethrogram (VCUG or cystogram) A catheter (a hollow, soft tube) is used to inject an opaque dye into the bladder. This X-ray test can diagnose VUR and identify problems with the bladder or urethra.
Cystoscopy A cystoscope uses lenses and a light source within a tube inserted through the urethra to directly view the inside of the bladder. It's used when other tests or symptoms indicate a possible bladder abnormality.
Intravenous pyelogram Opaque dye is injected into a vein, and then X-rays are taken to follow the course of the dye through the urinary system. Although this test is still used sometimes, the renal MRI and renal scan have replaced intravenous pyelogram in most cases.
Magnetic resonance urography (MR-U) This procedure, which makes a magnetic resonance imaging (MRI) scan of the urinary tract without the use of dyes or radioactive materials, has been shown to be as accurate as other scans and is now typically done in place of an intravenous pyelogram.
Treatment for recurrent UTIs depends on what's causing them in the first place. Sometimes the answer is as simple as teaching a child to empty the bladder as soon as he or she has the urge to go.
If a condition like VUR is causing the infections, then the solution is a bit more complicated. Kids with VUR must be monitored closely, because the condition can lead to kidney infection (pyelonephritis) and subsequent kidney damage. Usually, surgery isn't necessary, because many kids outgrow the condition.
Some kids with VUR benefit from daily treatment with a small amount of antibiotics, which can also make surgery unnecessary. Kids with VUR should be examined by a pediatric urologist to decide if antibiotic treatment is the best option for them.
In some cases, surgery is necessary to correct VUR. The most common type of surgery used is ureteral reimplantation, in which one or both of the ureters are repositioned to correct the backflow of urine from the bladder. The procedure can be done through a small incision. The success rate for this surgery is high, although not everyone is a good candidate for surgery.
Kids with the following situations may be candidates for ureteral reimplantation:
intolerance to antibiotics
recurrent infections while on antibiotic treatment
severe, or "high-grade," reflux
older kids and teens with reflux
An alternative to ureteral reimplantation is endoscopic injection of a material to block the entry of the ureter into the bladder and prevent VUR. In this procedure, a narrow tube called an endoscope is inserted through the urethra into the bladder. The endoscope has a tiny camera at the tip, allowing the surgeon to guide it to the proper location and inject the material, which helps keep urine from refluxing back into the kidneys. Endoscopic injection is less invasive than surgery, but the results are not as good. A pediatric urologist can help families decide the best treatment for a child with VUR.
Kids who have recurrent infections that are not caused by anatomical defects or other treatable problems may be prescribed antibiotics for months or even years to prevent recurrent infections. This form of treatment is known as continuous antibiotic prophylaxis.
The Future for Managing Recurrent UTIs
Recent studies have found that women and kids who get recurrent UTIs may lack certain immunoglobins (a group of proteins that fight infections). Some researchers are optimistic that a vaccine may be developed to help boost production of antibodies that fight UTIs. A promising vaccine that would protect against E. coli (the most common bacterium that causes UTIs) is being tested.
Additional things to consider to help prevent recurrent UTIs in kids:
Diet Modifications Encourage kids to drink 8 to 10 glasses of water and other fluids per day. Cranberry juice and cranberry extract are often suggested because they may prevent E. coli from attaching to the walls of the bladder. Always ask your doctor, though, if your child should drink cranberry juice or cranberry extract, because they can interfere with some medicines.
Good Bathroom Habits Frequent emptying of the bladder, normal urination and prevention of constipation can all help to prevent recurrent infections.
Multivitamins Vitamin C acidifies the urine, making the environment less friendly to bacteria. Vitamins designed for kids are generally safe, but always ask your doctor before increasing the dose beyond the currently recommended daily allowance.
No Bubble Baths Kids should avoid bubble baths and perfumed soaps because they can irritate the urethra.
Frequent Diaper Changes Kids in diapers should be changed frequently to prevent stool from having prolonged contact with the genital area, which can increase the chance that bacteria will move up the urethra and into the bladder.
Proper Wiping Technique In females, wiping from front to back after using the toilet will reduce exposure of the urethra to UTI-causing bacteria in the stool.
Cotton Underwear Breathable cotton underwear is less likely to encourage bacterial growth near the urethra than nylon or other fabrics.
Frequent Bathroom Visits Some kids may object to using the school bathroom or may become so engrossed in a project that they delay urination. Kids with UTIs should pee at least every 3 to 4 hours to help flush bacteria from the urinary tract.
When to Call the Doctor
As soon as you suspect that your child has a UTI, it's important to contact your doctor. The doctor may recommend another urine culture after treatment to be sure that the infection has cleared.
If your child suffers from recurrent UTIs, consult a pediatric urologist, who can perform a thorough evaluation and, if necessary, order tests for urinary system abnormalities. In the meantime, follow your doctor's instructions for treating a UTI.
Reviewed by: T. Ernesto Figueroa, MD
Date reviewed: May 14, 2016