Kidney stones common but mild in children with CF, new study finds
Most cases did not require surgery and kidney function was largely normal
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Kidney stones are commonly detected in children with cystic fibrosis (CF), but are often small and do not require surgical treatment, according to a new study from Turkey.
Nearly a fifth of the children evaluated in the study had kidney stones detectable by ultrasound, and even more had evidence of crystals in their urine. However, none of the cases required surgical intervention, and most measures of kidney health were within normal or age-appropriate ranges.
“In this retrospective cohort of children with CF, we found that urinary abnormalities—defined as [kidney stones or crystals in urine]—were relatively common, whereas overt [kidney] dysfunction was uncommon,” the researchers wrote.
The study, “Urinary System Involvement in Children With Cystic Fibrosis: A Single-Center Retrospective Cohort,” was published in Pediatric Pulmonology.
Study explores how cystic fibrosis may affect kidney health
CF is a genetic disease marked by abnormally thick, sticky mucus that builds up in organs. The disease often causes problems with the lungs and digestive system, and researchers have extensively studied these effects. However, CF can also affect other organs throughout the body, and these effects have received less attention.
The kidneys are a pair of organs located in the abdomen that filter the blood, removing excess fluid and waste that are passed out in urine. Kidney stones are hard deposits made of salts and minerals that can cause severe pain and, in some cases, kidney damage.
Little is known about how CF affects kidney health or the risk of kidney stones. Most of the available data come from studies of adults with CF. Researchers at Gaziantep City Hospital in Turkey set out to better understand how CF affects kidney health in children.
“No study has been conducted in our country focusing specially on urinary system involvement in children with CF, and most available data are based on adult populations,” the scientists wrote.
Study examines kidney stones and urine changes in children with CF
The researchers reviewed clinical data from 41 children with CF who had at least one urine sample available for analysis. Urine analyses found that 13 (31.7%) of the 41 children tested positive for calcium oxalate crystalluria, meaning they had tiny calcium-based crystals that can form kidney stones.
On abdominal ultrasound, eight (19.5%) of the children had detectable kidney stones. These stones were mostly small — the median size was just 3 millimeters — and none caused serious health problems or required surgery. The researchers noted that most of the stones were located in the lower part of the kidneys, where urine can collect and stones may be less likely to pass on their own.
Apart from the relatively high rate of kidney stones, most measures of kidney function were within normal or age-appropriate ranges. The researchers noted that some differences in kidney test results were “unlikely to reflect clinically meaningful renal dysfunction and may be influenced by factors such as hydration status or dietary protein intake.”
The researchers stressed that their study is limited to a relatively small number of patients at a single center. They called for additional research to better understand how CF affects the kidneys and other organs, writing, “Prospective studies incorporating comprehensive [kidney] stone assessments are needed to confirm these findings and clarify their long‐term clinical implications.”
