Evaluation of risk factors in childhood urinary stone patients

Objective: The prevalence of urinary system stone disease affects individuals across all age groups, including children, and its incidence is on the rise. Failure to adequately treat kidney stones, especially those prone to recurring, can result in significant morbidity. The risk factors associated with the development of urinary system stones differ depending on age, gender, genetic factors, and geographical location within our country. The objective of this study was to identify region-specific risk factors by analyzing clinical and laboratory findings of kidney stone patients from the OMU Pediatric Nephrology Clinic, a prominent facility in the Central Black Sea region, while also evaluating their follow-up and treatment outcomes. Materials and Methods: The study included individuals between the ages of 0 and 18 who were diagnosed with kidney stones and visited the outpatient clinic from January 1, 2018, to December 31, 2021. Patient records were retrospectively examined to collect demographic, clinical, laboratory, and treatment-related information. Results: Among the 163 patients included in the study, 59.5% were male. The median age at presentation was 22.9 months (range: 1-196 months), and the median age at diagnosis was 11 months. Most cases (74.8%) were followed up for nephrolithiasis (stone size > 3 mm), and 72.4% had multiple stones. The majority of cases of microlithiasis (stone size ≤ 3 mm) were observed in infants younger than six months, and a significant proportion of stones (94.4%) were located in the renal parenchyma, calyx, and pelvis. Risk factors identified included a history of premature birth in 10.7% of cases, a family history of stones in 75% of cases, associated renal and systemic conditions in 28% of cases, and underlying functional or structural renal anomalies in 12% of cases. Metabolic risk factors were identified in 70% of cases, with hypercalciuria (36.2%) being the most common, followed by hypocitraturia (35.2%), hyperoxaluria (28.8%), and hyperuricosuria (18.8%). There were no significant differences in metabolic risk factors between stone sizes or between genders. Hypercalciuria was equally prevalent in all age groups (p=0.605). Hypocitraturia was primarily observed in children older than six months (p=0.016), while hyperoxaluria and hyperuricosuria were more common in children older than two years (p=0.003 and p=0.001, respectively). Among the 33 patients who underwent stone analysis, calcium oxalate stones were the most common type (25 patients, 75.8%). Surgical intervention was performed in 30.7% of patients, while 77.3% of the conservative management group received medical drug treatment. Potassium citrate was the most frequently prescribed medication (97.6%). After one year of follow-up, 61% of patients were stone-free, which increased to 68% after two years. For patients with microlithiasis, stones were not detected in 43.9% at six months and in 70.4% at twelve months of follow-up. Among patients with nephrolithiasis, stones were not detected in 55.6% at twelve months of follow-up. There was no statistically significant difference in stone resolution rates between patients who received medication and those who did not (p=0.09). Gender did not affect stone-free rates at both one-year and mean follow-up periods (p values: 0.699 and 0.832, respectively). When evaluating the effect of medication on stone resolution separately in patients with microlithiasis and nephrolithiasis, no statistically significant difference was found (p values: 0.873 and 0.282, respectively). Conclusion: Consistent with existing literature, the majority of our cases exhibited multiple stones larger than 3 mm and were predominantly male. In our region, hypercalciuria was identified as the most common risk factor for kidney stones, while hypocitraturia was more prevalent in children older than six months, and hyperoxaluria and hyperuricosuria were more notable in children older than two years. Based on one-year follow-up data, approximately half of the patients with nephrolithiasis achieved stone resolution, with even higher rates observed in patients with microlithiasis. The use of medication and gender did not significantly impact stone resolution rates in either group. The significant rates of stone resolution in microlithiasis and the limited impact of medication emphasize the importance of conservative supportive treatment and ongoing monitoring. Keywords: Kidney stone, child, nephrolithiasis, urolithiasis