IN BRIEF

Does Low Baseline Renal Volume Lead to Renal Insufficiency in Children With Cloacal Anomalies?

November 10, 2020
Written by

Patients with cloacal anomalies are at a high risk of renal insufficiency, but it is unknown if the underlying cause is iatrogenic or congenital.

According to the results of a recent study published in Urology, children with cloacal anomalies have baseline renal volumes similar to those of children without cloacal anomalies, indicating that the increased risk of renal insufficiency in children with cloacal anomalies appears to be due to postnatal renal injury.

“Before we can determine if surgical interventions or other medical procedures are causing renal insufficiency in patients with cloacal anomalies, we need to evaluate what their baseline renal function is,” says Molly Fuchs, MD, pediatric urologist at Nationwide Children’s and senior author of the study.

The investigators aimed to determine the baseline renal volume in children with cloacal anomalies compared to controls and hypothesized that children with cloacal anomalies would be born with less renal volume. To do so, they reviewed data from a prospectively maintained database of children with cloacal anomalies treated at Nationwide Children’s.

The study cohort included 109 patients, 46 (42.2%) patients with cloacal anomalies and 63 (57.8%) controls, who had had renal ultrasound within the first three months of life. Patients with cross fused ectopic kidneys or horseshoe kidneys (n = 6) were excluded from the analysis due to difficulty measuring their renal volume with ultrasound.

No significant difference was observed in renal unit volume among cloaca patients with both kidneys (n=30) and controls, even when controlling for age differences (adjusted difference, 0.2; 95% CI: -1.7 – 2.2; P = 0.824). To the authors’ surprise, cloaca patients with hydrocolpos or hydrometrocolpos (n = 19) had renal volumes similar to those of cloaca patients without utero obstructions.

“This is a really important piece of the puzzle,” says first author of the study Alexandra Rehfuss, MD, who was a fellow at Nationwide Children’s when the study was conducted and is now a pediatric urologist at Albany Medical Center in New York. “Patients with cloacal anomalies are extremely rare, and we are fortunate at Nationwide Children’s to have a large cohort of these patients to be able to gain some insight into why they are at higher risk for going into renal failure compared to people without cloacal anomalies.”

The team also found that cloaca patients with solitary kidneys (n=10) had significantly larger renal volume than controls and cloaca patients with both kidneys (adjusted difference, 5.3; 95% CI: 1.8 – 8.7; P=.003), consistent with compensatory hypertrophy in individuals with solitary kidneys.

“Renal failure is a condition that can develop silently, without any obvious symptoms. So, it’s not uncommon for a patient’s kidneys to be failing, and they don’t realize it,” explains Dr. Fuchs. “That’s why we are very aggressive about proactively monitoring and continuing to monitor these children into adulthood and lifelong to make sure that as they grow and change that their kidneys remain safe.”

Going forward, Nationwide Children’s and the pediatric urology team are well positioned to begin addressing more complicated questions about the nature of renal insufficiency in children with cloacal anomalies and to investigate effective management strategies that could potentially improve outcomes of these patients.

“We need to evaluate interventions that may inadvertently put these children at risk and remember that their kidney health is the most important factor that we need to consider for every decision we make about their health,” says Dr. Fuchs.

 

Reference

Rehfuss A, Bourgeois T, Thompson B, Sebastião YV, Wood RJ, Jayanthi VR, Fuchs ME. Baseline renal volumes in children born with cloacal anomalies. Urology. 2020 Aug 19;S0090-4295(20)30997-3. 

Photo credit: Adobe Stock