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hydronephrosis

A New Pathway for Prenatal Hydronephrosis

A model of the kidney (Stock photo)

By Rachel Arterberry

A multidisciplinary team at Children’s of Alabama and the University of Alabama at Birmingham (UAB) has developed a standardized clinical pathway for newborns diagnosed prenatally with hydronephrosis, reducing variability in care, improving coordination among specialties, and helping families receive timely guidance without unnecessary testing or travel.

The pathway, developed by general pediatricians in the newborn nursery in collaboration with pediatric nephrology and pediatric urology, provides a risk-stratified approach to determining which infants require immediate evaluation, which can be safely monitored, and which need little to no intervention. The initiative has already prompted changes in workflow, increased access to telehealth services, and generated interest from providers outside Birmingham.

Prenatal hydronephrosis, or dilation of the kidney’s collecting system, is one of the most common abnormalities identified on prenatal ultrasound. While some cases resolve spontaneously, others may signal underlying conditions such as urinary tract obstruction, vesicoureteral reflux, urinary tract infection risk, or chronic kidney disease. Determining which infants need urgent intervention has historically been challenging.

“We found the existing guidelines confusing,” said Terry Wall, M.D., division director of the UAB Division of Academic General Pediatrics and attending physician in the newborn nursery. “Different specialties interpreted them differently, radiology reports varied in terminology, and there was a lot of inconsistency in how babies were evaluated and referred.”

Wall, who is also a medical informaticist, brought together leaders in pediatric nephrology and pediatric urology to create a single algorithm that could be used consistently by nursery physicians, specialists, radiologists, and obstetric providers.

The resulting pathway categorizes infants based on prenatal and postnatal imaging findings, including the degree of hydronephrosis, bladder abnormalities, and progression over time. Infants identified as high risk are evaluated by urology or nephrology before discharge, while lower-risk patients receive targeted education and follow-up recommendations.

David Askenazi, M.D., pediatric nephrologist and medical director of the Pediatric and Infant Center for Acute Nephrology at UAB, said the pathway was designed with two goals in mind: ensuring that babies with significant disease are identified early while avoiding unnecessary interventions for families whose infants are unlikely to require treatment.

“We don’t want to miss a child who needs to be seen right away, but we also don’t want to burden families when their baby has a mild finding that is likely to resolve,” Askenazi said.

For infants requiring specialty follow-up, the pathway introduced another innovation. Stacy Tanaka, M.D., chief of pediatric urology, established a telehealth model that allows families to meet with pediatric urologists approximately two weeks after discharge.

Previously, referrals often occurred through community pediatricians, and specialists frequently lacked access to postnatal imaging before the initial visit. Families would travel to Birmingham for an appointment, only to learn that additional studies were needed.

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Now, newborn ultrasounds are obtained before discharge when indicated, and specialists can review imaging in advance of the telehealth visit. During these appointments, providers discuss results, explain whether additional testing is needed, determine if antibiotic prophylaxis is appropriate, and establish a plan for ongoing surveillance.

“It has helped our workflow tremendously,” Tanaka said. “It also allows us to set expectations for families much earlier. If they need another study, they know why. If the hydronephrosis is likely to resolve, they understand what we’re watching and what to expect.”

This approach is particularly beneficial for families traveling from rural communities or other regions of Alabama. Parents of newborns can participate in appointments from home rather than making repeated trips for visits that may not require in-person evaluation.

The pathway also has strengthened communication among departments. Discussions with radiology and obstetrics have focused on standardizing prenatal ultrasound reporting so nursery providers can more easily place patients into the appropriate risk category.

Although the initiative was implemented only recently, providers say it already has reduced confusion, improved consistency, and enhanced education for both families and primary care physicians.

The work ultimately may extend beyond Children’s. Tanaka has shared the algorithm with pediatric urologists in Mobile, Ala., and Askenazi plans to discuss the model with colleagues in the Neonatal Kidney Collaborative, an international network focused on improving kidney care for newborns. “We’ve worked out many of the details,” Wall said. “If other centers can use what we’ve learned to standardize care and improve outcomes for families, that’s a win for everyone.”

July 24, 2026 by childrensal

Urology

A new protocol for kidney tests in spina bifida patients

A new study shows that ultrasound is not enough to monitor kidney health in children with spina bifida. (Stock photo)

For decades, doctors have relied heavily on ultrasound scans to monitor kidney health in children with spina bifida, the most common permanently disabling birth defect in the U.S. People with spina bifida tend to develop end-stage renal disease up to 20 years earlier than the general population, so keeping a close watch on kidney health from a young age is important, says Children’s of Alabama pediatric urologist Stacy Tanaka, M.D. “Then if there’s a concern, it can be acted upon early and not ignored.”

Current guidelines from the Spina Bifida Association (SBA) recommend annual screening with ultrasound to look for hydronephrosis—a condition in which the urine backs up into one or more kidneys—as a sign of kidney function, and blood tests like serum creatinine, to measure overall kidney health. But with kids, Tanaka says, “the practice pattern was that a lot of people were only doing renal ultrasound.”

Now a new study from Tanaka and her Children’s colleague David Joseph, M.D., as well as other kidney experts from around the country, shows that ultrasound alone is not enough to assess kidney health. “We basically use ultrasonography as a reflection of renal function,” Joseph said, but few, if any, studies assessed its accuracy in determining renal function.

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The study’s genesis came during a multidisciplinary meeting in 2003 of specialists who treat children with spina bifida. “The bottom line from all disciplines at that time was that nobody was really treating this population with evidence-based care,” Joseph said.

To change that, the Centers for Disease Control and Prevention and the SBA established the National Spinal Bifida Patient Registry (NSBPR), to which 20 spina bifida clinics submit data to help develop evidence-based care. In addition, nine clinics established a urologic protocol to manage and preserve initial renal function in young children with spina bifida (UMPIRE). The NSBPR and UMPIRE provided the data set Joseph and Tanaka used to determine the effectiveness of renal ultrasound vs. blood test to assess renal function.

The two registries included data on 2,500 children ages 1-18 with myelomeningocele, the most severe form of spina bifida. All had had an ultrasound and blood test within six months to determine estimated glomerular filtration rate (eGFR), a marker of kidney health.

The results were striking: ultrasound-based detection of hydronephrosis had only about a 25% sensitivity for identifying children with signs of chronic kidney disease in the UMPIRE study and 24% in the NSBPR cohort. That means kidney damage in three out of four children was going undetected. The poor sensitivity held even when researchers looked only at severe hydronephrosis, which had an even worse sensitivity rate–just 6% to 11%. “The renal ultrasound by itself wasn’t all that good,” Joseph said, “but that didn’t surprise us.”

The findings challenge current practice and suggest that blood tests measuring kidney function should be routinely performed alongside ultrasound, not just when ultrasound results look concerning, as some clinicians practice. The team at Children’s prefers testing for cystatin C rather than creatinine because of the test’s improved and more accurate ability to obtain an eGFR.

One reason clinicians may eschew blood tests is that it involves needles, Tanaka said, which be traumatizing for children. Ultrasound, on the other hand, is noninvasive, easily available, and can be performed by technicians.

“The ultrasound is very helpful and important,” Joseph said, “but you need to recognize that it may not be telling you about renal function or injury to the kidney.” The findings have already changed practice at Children’s, where all kids with spina bifida now receive both tests during kidney health screening.

Ideally, the next study would randomize kids to either double testing or ultrasound alone, but that requires significant funding, particularly since the children would need to be followed for years.

This study was conducted with very little financial support, Tanaka said. “It represents a labor of love for everyone at all nine UMPRIE centers who have been involved in this project,” Joseph added.

July 25, 2025 by childrensal