Search Results (288)

Objectives: This study compared the risk profiles, nutrient intake, and kidney function of calcium oxalate stone formers with and without enteric hyperoxaluria. Methods: Thirty-seven patients with calcium oxalate stone disease and enteric hyperoxaluria (cases) and 37 sex- and age-matched idiopathic calcium oxalate stone formers (controls) were enrolled. Patients did not receive any nutritional counseling prior to the start of the study, and they discontinued medications affecting urinary parameters four weeks before their study participation. Anthropometric, clinical, and metabolic parameters were recorded. Dietary and 24-h urinary variables were measured under the habitual diet and under a balanced, standardized diet. The [¹³C₂] oxalate absorption and calcium loading tests were carried out. Results: The median [¹³C₂] oxalate absorption was significantly higher in cases (14.8%) than in controls (8.9%). Under the balanced diet, hypocitraturia, hypomagnesuria, low urine volume and pH value were significantly more common in the case group, whereas hypercalciuria occurred more frequently in the control group, affecting 45.9% of controls and 5.4% of cases. Furthermore, the control group exhibited a greater reduction in urinary calcium excretion under the balanced diet. Urinary oxalate excretion and the ion-activity product index of calcium oxalate were significantly higher under both diets, with a greater decline observed in the case group under the balanced diet. The estimated glomerular filtration rate (eGFR) was lower in cases. A multivariable linear regression analysis revealed a significant association between urine pH and eGFR. Conclusions: Calcium oxalate stone formers with and without enteric hyperoxaluria benefit from a balanced diet and sufficient fluid intake. The reduction in urinary oxalate excretion and the biochemical risk of recurrent calcium oxalate stone formation were even more pronounced in patients with enteric hyperoxaluria. Particular attention should be paid to low urine pH, as it is hypothesized to be a potential indicator of impaired kidney function. Full article

Background and Objectives: Multidrug-resistant (MDR) uropathogens are reshaping the empirical management of acute pyelonephritis, particularly in Eastern European centers. We aimed to describe MDR patterns, identify admission-level predictors, including renal impairment/renal-failure status at presentation and major healthcare exposure variables, and derive a bedside risk score (PYELO-MDR-Risk) for adult pyelonephritis at a Romanian tertiary hospital. Methods: We retrospectively analyzed 129 consecutive culture-confirmed acute pyelonephritis admissions at “Victor Babeș” University Hospital, Timișoara (March 2022–March 2025). MDR was defined as non-susceptibility to ≥1 agent in ≥3 antimicrobial categories. We compared MDR and non-MDR cases on demographics, microbiology, time-to-effective therapy (TTE), and outcomes; multivariable logistic regression identified independent predictors and was the basis for a points-based score with bootstrap-based internal validation (1000 resamples). Results: Fifty-four patients (41.9%) had MDR pyelonephritis. Escherichia coli remained the dominant uropathogen (55.8%) but was less prevalent in the MDR group (40.7% vs. 66.7%; p = 0.003), whereas Klebsiella pneumoniae and Pseudomonas aeruginosa were enriched. Independent predictors of MDR were antibiotic exposure ≤90 days (aOR 5.7, 95% CI 2.4–13.6), recurrent UTI (aOR 3.4, 1.4–8.2), recent hospitalization (aOR 3.1, 1.2–8.0), and renal impairment/renal-failure status at admission (aOR 2.4, 1.0–6.2). Immunosuppression, prior urinary tract instrumentation, and nephrolithiasis/urolithiasis were evaluated as candidate predictors but did not independently improve the final point score after adjustment. MDR was associated with delayed effective therapy (28.4 vs. 9.7 h; p < 0.001), longer hospitalization (13.7 vs. 8.9 days; p < 0.001), and higher 30-day readmission (20.4% vs. 8.0%; p = 0.038). The PYELO-MDR-Risk score (range 0–12) achieved an optimism-corrected AUC of 0.84 with adequate calibration (Hosmer–Lemeshow p = 0.624). Conclusions: MDR drives a substantial fraction of pyelonephritis admissions in Western Romania and tracks closely with prior antibiotic and healthcare exposure. The PYELO-MDR-Risk score offers a transparent bedside tool for empirical-therapy decisions in the local setting, pending national and international external validation. Full article

The objective of these three studies was to determine if dietary potassium supplementation affects urine production or calcium oxalate (CaOx) relative supersaturation (RSS) in adult cats. In the first study, control cats were fed dry food containing 1.08% potassium (as fed), and treatment cats were fed control food supplemented with KCl (1.95% potassium) for 21 days. In study two, cats were fed one of three treatment foods for two weeks in a three-period crossover study design (control food containing 0.84% potassium, and treatment foods containing control food supplemented with KCl at 1.35% or 1.81% potassium). In study three, control and treatment cats were fed similarly to study one, with each experimental period lasting two weeks in a crossover study design. In study one, urine production (p = 0.037), urine potassium excretion (p = 0.049), and urine chloride excretion (p = 0.007) were greater for cats fed test food. In study two, increasing dietary potassium concentration significantly increased water intake and urine production, and decreased USG in a dose–response manner. Urine concentrations of sodium and phosphorus were significantly decreased by urine dilution. In study three, cats consuming test food had a 25% increase in urine production and reduced urine specific gravity compared with cats consuming the control food. In addition, CaOx RSS was reduced (p = 0.007). No adverse effects were observed in healthy cats consuming increased dietary potassium. Full article

Background/Objectives: Kidney stone patients struggle to attain the recommended fluid intake. Prior work has focused on the strength of habits (i.e., context–behavior associations) for fluid intake, but given the variability in the contexts of daily life, the scope of efforts to create opportunities to drink across contexts may also be important. Methods: A cross-sectional study was conducted among adults with a history of kidney stones (N = 265). Participants identified situations in which they made an effort to have a glass of water nearby (opportunity creation), rated the experienced automaticity of water intake (i.e., habit strength, measured via the Self-Report Behavioral Automaticity Index), and reported past-week fluid intake volumes. Latent class analysis was used to identify distinct subgroups based on the contexts in which individuals created opportunities to drink, and multivariable linear regression was used to examine the associations between habit strength, class membership, and daily fluid intake. Results: Three latent classes were identified based on the scope of opportunity creation across contexts: widespread (27.9% of the sample; water intake: 41.2 $\pm$ 17.1 fl oz), selective (43.4%; water intake: 32.6 $\pm$ 16.33 fl oz), and limited (28.7%; water intake: 19.01 $\pm$ 16.08 fl oz). The widespread class reported stronger habits (22.45 $\pm$ 6.43) and higher water intake than the selective (19.97 $\pm$ 6.20) or limited classes (14.38 $\pm$ 6.81) (all Ps < 0.001). Stronger habits significantly predicted higher daily water intake (b = 0.90, SE = 0.16, p < 0.001). No significant association was found between habit strength and total fluid intake volume (b = 1.06, SE = 0.74, p = 0.17). Conclusions: Habit strength positively predicted water intake for all classes. To increase fluid intake, clinical interventions should help patients develop drinking habits tied to specific daily contexts. Full article

A 14-year-old spayed female Maltese dog presented with hematuria, pollakiuria, decreased urine volume per voiding, and prolonged urination time, and was diagnosed with multifactorial urinary obstruction involving suspected trigonal neoplasia and extensive urolithiasis affecting the kidneys, ureters, bladder, and urethra. Diagnosis was based on serum biochemical analysis, radiography, and ultrasonography, which revealed diffuse urolithiasis, urethral involvement, and a trigonal mass consistent with a suspected neoplastic lesion. Due to the multifocal nature of obstruction, surgical management was considered impractical. The patient underwent urethral stent placement as a minimally invasive palliative intervention. Following the procedure, rapid restoration of urine flow was achieved, and significant improvement in renal parameters, including blood urea nitrogen and creatinine, was observed within 3 days. During follow-up, the stent remained well positioned without migration. Although transient deterioration, including hydronephrosis and increased renal parameters, was noted at day 52, subsequent improvement was observed by day 64, suggesting a dynamic course of obstruction. This case demonstrates that urethral stenting can be an effective treatment option for managing complex, multifactorial lower urinary tract obstruction in dogs, providing rapid clinical improvement and sustained urinary patency. However, progressive changes in the upper urinary tract may occur, emphasizing the importance of comprehensive evaluation and continuous monitoring. Full article

Background/Objectives: Recently, a 6.3 Fr single-use flexible ureteroscope (f-URS) was introduced to the market. The purpose of this pilot study is to present our experience with it during Endoscopic Combined Intrarenal Surgery (ECIRS) and to compare its performance with the conventional 7.5 Fr scope. Methods: For percutaneous access, renal puncture was performed in a nonpapillary approach. Regarding retrograde access, for the first group, a 7.5 Fr single-use f-URS was used, while for the second group, a 6.3 Fr single-use f-URS was utilized. Lithotripsy was primarily performed in an antegrade manner, using the Lithoclast Trilogy^®. In cases where stones could not be reached with a nephroscope, retrograde lithotripsy was performed with either a Holmium:YAG laser or a Thulium Fiber Laser. Results: In total, 45 patients were included. Of these, 23 patients underwent ECIRS with the 6.3 Fr f-URS and 22 with the 7.5 Fr f-URS. The mean operative time, fluoroscopy time and lasing time were 59.5 ± 5.6 min, 139.7 ± 14.2 s and 18.4 ± 2.7 min in the 6.3 Fr group and 57.1 ± 3.9 min, 133.8 ± 29.7 s and 18.6 ± 1.9 min in the 7.5 Fr group, respectively. Two patients in the 6.3 Fr group and three patients in the 7.5 Fr group experienced Grade II complications. Stone-free rates were 91.3% in the 6.3 Fr group versus 86.4% in the 7.5 Fr group. Conclusions: The use of a 6.3 Fr f-URS during ECIRS is potentially a feasible, safe and efficient approach. Both the 6.3 Fr and 7.5 Fr scopes were associated with comparable outcomes during ECIRS. Additional studies are needed so as to draw safer conclusions. Full article

Background: Rising healthcare demands and the impact of the COVID-19 pandemic have prompted a transition from inpatient to day-case ureterorenoscopy (URS) to reduce costs and optimise bed capacity. Although international studies support the safety of day-case URS, evidence from The Netherlands is limited. Furthermore, Dutch and European urological guidelines do not provide explicit recommendations for standardising URS as a day-case procedure. The present study compares 30-day complication rates of URS between the pre-COVID-19 era (2019) and current practice (2023). Methods: A retrospective cohort study was conducted, including all patients who underwent elective URS at Canisius Wilhelmina Hospital, the Netherlands, in 2019 and 2023. Patients under 18 years of age, as well as those undergoing emergency procedures and combined procedures, were excluded. The primary outcome was the occurrence of complications within 30 days, classified according to the Clavien–Dindo system. Secondary outcomes included identification of clinical and procedural predictors of complications. Statistical analysis was performed using SPSS and included Chi-square tests, t-tests, Mann–Whitney U tests, and multivariable logistic regression. Results: Of 619 screened patients, 495 were included: 230 patients in 2019, 265 patients in 2023. Baseline characteristics were comparable between groups. The overall complication rate was low (15.7% in 2019, 20.0% in 2023) and did not differ significantly between day-case and inpatient URS (p = 0.209). In multivariable logistic regression, day-case URS was not associated with an increased risk of complications (OR = 0.91, 95% CI 0.46–1.81, p = 0.795). There were no other significant predictors of complications. Conclusions: The findings suggest that day-case ureterorenoscopy may be a safe and feasible approach and may offer opportunities for cost savings, as no increase in postoperative complications was observed compared with inpatient procedures. However, these results should be interpreted with caution given the observational design. Full article

Urolithiasis is a condition characterized by the crystallization of urinary solutes and their accumulation as solid aggregates in the urinary tract. Effective pharmacological strategies for preventing crystal formation and oxidative stress-related urinary disorders remain limited. Mimosa malacophylla is traditionally used in northeastern Mexico for kidney disorders; however, its biological activities have not been fully characterized. In this study, a methanolic extract of M. malacophylla was obtained by maceration and evaluated for its phytochemical profile and biological activities. Preliminary phytochemical screening, total phenolic content, and high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS) were used to characterize the extract. Antiurolithic activity was assessed by a calcium oxalate nucleation assay, while antioxidant, antimicrobial, hemolytic, and brine shrimp lethality assays were also performed. The extract showed a yield of 6.25% (w/w) and a total phenolic content of 6.41 mg GAE/g of extract. HPLC-MS analysis revealed a profile rich in flavonoid glycosides and phenolic derivatives, including rutin, luteolin, and apigenin. The extract exhibited under in vitro conditions a high inhibitory effect on calcium oxalate nucleation (95.47%) and notable antioxidant capacity, while no antibacterial activity was detected. Hemolysis was below 1% and the LD₅₀ in Artemia salina was 1174.23 ± 17.94 μg/mL. These findings suggest that M. malacophylla may be a source of bioactive compounds with potential relevance in early stages of crystal formation for the management of urolithiasis. Full article

Background/Objectives: Intraoperative cone-beam computed tomography (CBCT) can detect residual fragments (RFs) during percutaneous nephrolithotomy (PCNL), enabling immediate removal and improving stone-free status. However, CBCT requires a hybrid operating room (OR), which is often limited in availability. This study explores patient and stone characteristics associated with CBCT eligibility and develops an exploratory treatment-selection model estimating stone-free probabilities conditional on CBCT use. Methods: We performed a retrospective study of a previously conducted randomized controlled trial evaluating intraoperative CBCT during PCNL in a tertiary care center. We compared CBCT-eligible cases versus ineligible cases, and cases achieving grade C (≤4 mm) stone-free status versus those with RFs. A multivariate exploratory treatment-selection model was developed using the strongest potential predictors of stone-free status. Internal validation was performed using bootstrapping. The model was also assessed for predicting grade A (0 mm) stone-free status. Results: The only significant difference between CBCT-eligible (n = 160) and ineligible (n = 60) cases was stone composition (p = 0.022). The final model included intraoperative CBCT (p = 0.003), stone size (p = 0.024), and composition (p = 0.044). Model-based estimates suggested smaller differences in predicted stone-free probabilities with CBCT in solitary stones. The AUC was 0.81 (95% CI: 0.73–0.88) for grade C and 0.75 for grade A (95% CI: 0.67–0.82) outcomes. Internal validation demonstrated moderate optimism, indicating potential overfitting. Conclusions: This exploratory treatment-selection model estimates conditional stone-free probabilities with and without CBCT. The findings suggest variation in expected benefit across stone characteristics but should be considered hypothesis-generating. The model is not intended for clinical decision-making and requires external validation before implementation. Full article

Background: Emergency department evaluation of suspected urolithiasis increasingly relies on non-contrast CT, yet not all patients require imaging. Existing clinical prediction rules help stratify stone probability, but by converting continuous measurements into fixed binary indicators, they offer little insight into why a particular patient is at risk or how much uncertainty remains after each testing stage—questions that bear directly on individualized diagnostic decisions. Methods: We retrospectively analyzed 1000 ED patients with suspected urolithiasis who underwent non-contrast CT (stone prevalence 85.0%). A gradient boosting classifier was trained on 17 continuous clinical and laboratory features and compared against binary-thresholded counterparts and an established scoring system; the 17-feature model achieved AUC 0.771 (95% CI 0.726–0.813) versus 0.723 (95% CI 0.675–0.771) for the reference score on this cohort (DeLong p = 0.001). Individual predictions were explained using an interventional Shapley value approach, and a Shannon entropy-based framework was applied to quantify the marginal diagnostic contribution of each sequential testing stage. Results: Held-out permutation importance identified red blood cell count on microscopy, age, pain duration, and prior stone history as the most influential predictors. Several features showed non-linear contributions that diverged from conventional binary thresholds: creatinine effect crossed zero near 0.90 mg/dL and pain duration peaked between 2 and 5 h. C-reactive protein, absent from existing scoring systems, emerged as a meaningful negative predictor. Sequential entropy analysis showed that dipstick urinalysis provided the largest marginal information gain among non-history stages (6.1% of prior entropy), while physical examination contributed 2.3%. A prevalence sensitivity analysis projected that the framework’s threshold behavior would differ substantially in lower-prevalence populations, underscoring that the cohort-specific cut-points are not portable decision rules. We therefore position the framework as a reasoning aid that complements clinical judgment and imaging, not as a stand-alone triage tool. Conclusions: Explainable machine learning can address questions that aggregate discrimination metrics cannot: which features drive risk for a given patient, how those effects behave across the continuous measurement range, and how much diagnostic uncertainty each testing stage resolves. The Shapley-based explanations and entropy framework developed here offer a structured approach to individualized diagnostic reasoning in the ED evaluation of suspected urolithiasis, functioning as an interpretive adjunct to, rather than a replacement for, existing clinical tools and CT imaging. Full article

Background/Objectives: Ureteric stents are commonly used in the management of urolithiasis but are associated with significant morbidity, leading to unplanned emergency department presentations and increased healthcare utilisation. This study aimed to evaluate whether reducing ureteric stent dwell time from three months to one month was associated with reduced stent-related emergency presentations. Secondary objectives were to assess post-ureteroscopy infective complications and identify predictors of emergency attendance. Methods: A retrospective cohort study was conducted across Western Sydney Local Health District, comparing patients undergoing ureteric stenting prior to ureteroscopy before (n = 189) and after (n = 244) an institutional policy change reducing time to definitive surgery from three months to one month. Patients aged ≥16 years with urolithiasis were included. Results: Following the policy change, mean waiting time for ureteroscopy decreased from 97.3 to 40.6 days. The proportion of patients presenting to the emergency department (ED) for stent-related symptoms decreased from 31.7% to 16.4% (p < 0.001), and mean presentations per patient declined from 0.60 to 0.21 (p < 0.001). Stent irritation accounted for most presentations. Using multivariable analysis, age < 50 years, immunosuppression, and positive pre-operative urine cultures were independently associated with ED attendance. Post-ureteroscopy infective complications were lower in the shortened dwell-time cohort (2.0% vs. 4.2%) but did not reach statistical significance (p = 0.26). Conclusions: Reducing routine ureteric stent dwell time from three months to one month was associated with significantly fewer stent-related emergency presentations. Shorter dwell protocols may reduce patient morbidity and healthcare utilisation and could be associated with lower rates of post-ureteroscopy infective complications. Full article

Objectives: Primary hyperoxaluria type III (PH3) causes kidney stones in children and adults. Gas chromatography/mass spectrometry (GC/MS)-based metabolomics has been applied to study patients with primary hyperoxaluria types I and II, 2,8-dihydroxyadenine lithiasis, and xanthinuria types I to III. This study was performed to verify the usefulness of this technique for the diagnosis of PH3. Specifically, we evaluated an 8-month-old infant with recurrent kidney stones. Methods: GC/MS-based metabolomics was performed on spot urine samples using initial urease pretreatment without fractionation. Results: Metabolomics revealed increased levels of 2,4-dihydroxyglutarate and 4-hydroxyglutamate. No simultaneous elevations of these two critical biomarkers were observed in other patients, except for one case of PH3 confirmed by the identification of HOGA1 mutations. A moderate increase in 4-hydroxyglutamate has been observed only in cases of primary hyperammonemia, in which analytes such as orotate, uridine, glutamine, or proline, but not 2,4-dihydroxyglutarate, are biomarkers, thus distinguishing PH3 from primary hyperammonemia. Conclusions: GC/MS-based urine metabolomics enables the rapid screening and chemical diagnosis of PH3 and other congenital anomalies that cause urolithiasis. This technique can also be used to monitor disease progression, as patients with PH3 benefit from long-term follow-up, particularly when transitioning from childhood to adulthood. The timely identification of patients with hereditary urolithiasis is crucial. To address this, a discussion was had about the current diagnostic criteria. Full article

Introduction: Acquired ureteral stricture is an uncommon but clinically relevant complication, mainly associated with long-standing urolithiasis, chronic inflammatory processes, and repeated endourological procedures. Case presentation: We present the case of a 48-year-old woman with left distal ureteral stricture secondary to urolithiasis and repeated endourological procedures, with a complicated clinical course and progressive renal functional impairment. Despite stepwise management including balloon dilations, endoscopic incision, prolonged urinary diversion, and ultimately ureteral reimplantation with a psoas hitch, the patient developed restenosis of the ureteral neomeatus. Due to persistent obstruction, endoscopic dilation with a paclitaxel-coated balloon (Optilume^®) was performed. Subsequent imaging demonstrated partial improvement in ureteral drainage and relative functional improvement of the left kidney. Conclusion: This case highlights the potential complementary role of drug-coated balloons in complex and refractory benign ureteral strictures, although the currently available evidence remains limited. Full article

Urinary stone disease is common, recurrent, and increasingly managed through imaging-driven pathways, yet standard-dose CT of the kidneys, ureters, and bladder (CT KUB) raises concerns about cumulative radiation exposure and the limited use of quantitative imaging information for risk stratification. This review synthesizes contemporary evidence on dose-optimized CT, advanced spectral technologies, and artificial intelligence (AI)-enabled analytics that are reshaping diagnosis, treatment selection, and triage. This review summarizes data supporting low-dose and ultra-low-dose CT protocols that preserve diagnostic accuracy while substantially reducing dose, and discusses how dual-energy CT, photon-counting CT, and radiomics facilitate noninvasive stone characterization and extraction of imaging biomarkers beyond size and location. It also reviews AI approaches for automated detection, segmentation, and volumetric quantification across CT, KUB, and ultrasounds, highlighting their potential to standardize stone-burden metrics. It further examines predictive models, including logistic regression, nomograms, and machine learning, for perioperative infectious complications, emergency department admission or intervention, procedure success, and long-term recurrence, and outlines reporting and validation frameworks and implementation considerations, including software as a medical device regulation and human oversight. In contrast to prior reviews that consider imaging and AI separately, this review integrates dose reduction, spectral characterization, and AI-driven analytics within real-world clinical pathways to distinguish established clinical applications from those that remain investigational. Integrating advanced CT and AI outputs into well-validated prediction models embedded in real-world workflows may enable safer imaging, more consistent triage, and more personalized follow-up for urinary stone disease. Full article

Background and Objectives: This meta-analysis aimed to compare the clinical efficacy and safety of the Thulium fiber laser (TFL) and Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) laser for ureteroscopic lithotripsy, considering the distinct technical characteristics of these two systems. Materials and Methods: Following the PRISMA guidelines and PROSPERO registration (CRD42023461573), a systematic search of PubMed, EMBASE, Cochrane Library, and Web of Science was conducted through August 2025. We included randomized controlled trials and non-randomized comparative studies comparing TFL and Ho:YAG laser in patients undergoing ureteroscopic management for urolithiasis. The primary outcomes were the stone-free rate (SFR) and complication rates (intraoperative and postoperative). Results: Thirteen studies involving 2217 patients were included. Overall, the TFL group demonstrated a significantly higher SFR compared to the Ho:YAG group (OR = 1.57, 95% CI 1.20–2.06, p = 0.001). In subgroup analysis, TFL showed superior SFR compared to Ho:YAG without pulse modulation (OR = 1.69, p = 0.01) and comparable efficacy to Ho:YAG with pulse modulation (OR = 1.52, p = 0.24). Regarding safety, no significant difference was observed in the intraoperative complication rate (OR = 0.77, 95% CI 0.35–1.70, p = 0.52) or the postoperative complication rate (OR = 1.02, 95% CI 0.65–1.60, p = 0.93) between the two groups. Conclusions: TFL provides a superior SFR compared to the Ho:YAG laser overall, a benefit primarily driven by its significant outperformance of standard Ho:YAG systems without pulse modulation. Importantly, TFL demonstrates comparable efficacy to modern Ho:YAG systems equipped with pulse modulation. The safety profile of TFL, including intraoperative and postoperative complications, is comparable to that of the Ho:YAG laser. Our findings suggest that TFL is a highly effective and safe modality for ureteroscopic lithotripsy, offering distinct advantages over standard Ho:YAG lasers while performing comparably to the latest pulse-modulated systems. Full article