Assessment of interleukin 17A and 23 in the course of bladder cancer and selected benign urological diseases.

Several cytokines have been indicated to be significantly involved in urological diseases. Interleukin 17A (IL-17A) and interleukin 23 (IL-23) have recently received attention for their involvement in inflammatory diseases and cancers. The aim of the study was to show changes in the level of pro-inflammatory interleukins IL-17A and IL-23 in patients with bladder cancer (BC) and selected urological diseases. An important cognitive aspect was to study the interdependencies between the studied interleukins and to assess their diagnostic value for such diseases. The material for the study was urine sample from patients with BC, urinary tract infection (UTI), urolithiasis, benign prostatic hyperplasia (BPH), US (urethral stricture), which was compared to the urine sample of healthy people without urological disorders. Interleukin concentrations were measured by the immunoenzymatic method. The levels of IL-17A and IL-23 in the urine of patients with BC, UTI, BPH and US were significantly higher compared to the control group. Statistically significant differences were found in the level of both interleukins compared to the control group in all diseases except urolithiasis. IL-17A and IL-23 correlated with each other in patients with all urological diseases except urolithiasis. The results of the conducted studies showed that selected urological diseases changed the levels of IL-17A and IL-23 in the urine of patients. The observations made confirmed the participation of these interleukins in the course of the urological diseases, especially in BC, and allowed to classify them as potentially useful parameters for diagnostic purposes.

Follow-up of urolithiasis patients after treatment: an algorithm from the EAU Urolithiasis Panel.

OBJECTIVE: To develop a follow-up algorithm for urinary stone patients after definitive treatment. MATERIALS AND METHODS: The panel performed a systematic review on follow-up of urinary stone patients after treatment (PROSPERO: CRD42020205739). Given the lack of comparative studies we critically evaluated the literature and reached a consensus on the follow-up scheme. RESULTS: A total of 76 studies were included in the analysis, including 17 RCTs. In the stone-free general population group, 71-100% of patients are stone-free at 12 months while 29-94% remain stone-free at 36 months. We propose counselling these patients on imaging versus discharge after the first year. The stone-free rate in high-risk patients not receiving targeted medical therapy is < 40% at 36 months, a fact that supports imaging, metabolic, and treatment monitoring follow-up once a year. Patients with residual fragments ≤ 4 mm have a spontaneous expulsion rate of 18-47% and a growth rate of 10-41% at 12 months, supporting annual imaging follow-up. Patients with residual fragments > 4 mm should be considered for surgical re-intervention based on the low spontaneous expulsion rate (13% at 1 year) and high risk of recurrence. Plain film KUB and/or kidney ultrasonography based on clinicians' preference and stone characteristics is the preferred imaging follow-up. Computed tomography should be considered if patient is symptomatic or intervention is planned. CONCLUSIONS: Based on evidence from the systematic review we propose, for the first time, a follow-up algorithm for patients after surgical stone treatment balancing the risks of stone recurrence against the burden of radiation from imaging studies.

Prevention, diagnosis, and treatment of urolithiasis in geriatric patients - differences, similarities and caveats in comparison to the general population.

PURPOSE OF REVIEW: Purpose of the review is to address management and prevention of urolithiasis in elderly patients examining the dynamic interplay between general measures, dietary adjustments, lifestyle modifications, and targeted pharmacological and/ or surgical interventions. The goal is to provide understanding of the evolving strategies required for effective urolithiasis prevention in the geriatric population. RECENT FINDINGS: Age-specific diagnostic considerations are necessary because urolithiasis in the elderly population is characterized by bigger stones, greater peri-operative risks, and heightened symptom severity. When comorbidities are present, conservative treatments - especially analgesia - provide difficulties. Surgical procedures prove to be safe and effective, with complication rates and practical application comparable to younger cohorts. Prevention approaches that include lifestyle changes and the investigation of novel pharmaceutical options such as sodium-dependent glucose co-transporter 2 (SGLT-2)-inhibitors are promising in the management of urolithiasis in the elderly population. SUMMARY: Our review offers a thorough investigation of urolithiasis in the elderly population, elucidating distinct clinical manifestations, complex diagnostic issues, and treatment implications. The safety and effectiveness of ureteroscopy in older patients, as well as the possible prophylactic function of SGLT-2-I, offer crucial insights for clinicians. Subsequent studies are necessary to enhance age-specific therapies, addressing the distinct obstacles presented by urolithiasis in the elderly population within this rapidly growing demographic.

[Prevention of recurrence of urolithiasis]. / Rezidivprävention der Urolithiasis.

Urolithiasis is one of the most frequent urological diseases. Identifying the causes of stone formation forms the basis for successful prevention of recurrence. Metabolic diagnostics and measures for prevention of recurrence are based on the assignment of the patient to a low-risk or high-risk group. Analysis of the urinary calculi is an essential prerequisite for identifying patients at risk. The general recommendations on diet and lifestyle are considered to be the basis of treatment. Depending on the type of stone and the individual biochemical risk profile of a patient, these general measures should be supplemented by targeted medical nutrition therapy and pharmacological treatment. Mixed stones can pose a challenge for the treatment and prevention of recurrence. A personalized treatment decision that takes the various components of mixed stones into account could further improve the prevention of recurrence of urolithiasis.

The Association of Urolithiasis with Uricosuria, Uricemia and their Combination.

BACKGROUND: There are conflicting data on the significance of hyperuricemia or hyperuricosuria in urolithiasis formation and on the need for medical treatment. OBJECTIVES: To assess the significance of hyperuricemia or hyperuricosuria in urolithiasis formation, particularly when hyperuricemia occurs with normal uricosuria. METHODS: The electronic medical records of patients treated in Haifa and the Western Galilee district of Clalit Health Services, Israel, were retrospectively screened for diagnosis of nephrolithiasis or renal or urinary tract/bladder calculi between February 2014 and April 2019. The diagnosis was confirmed by ultrasonography or computed tomography. The study group included patients with one of these diagnoses. Patients in the control group did not have these diagnoses. The inclusion criterion for all patients was the presence of both serum and urinary uric acid levels. RESULTS: The study group included 359 patients and the control group 267. After adjustment by logistic regression, we found no significant differences in the prevalence of hyperuricosuria in the study group (14.8%) compared to the control group (9.7%), odds ratio (OR) 1.54 (95% confidence interval [95%CI] 0.74-3.2, P = 0.245). No significant differences between the groups were observed for hyperuricemia prevalence (45.4% vs. 55.1%, respectively, OR 0.82, 95%CI 0.54-1.25, P = 0.355), nor among those without hyperuricosuria (OR 0.83, 95%CI 0.52-1.33, P = 0.438) and after propensity score matching (OR 0.93, 95%CI 0.66-1.3, P = 0.655). CONCLUSIONS: There were no significant differences in hyperuricemia or hyperuricosuria between the two groups of patients or in hyperuricemia among participants without hyperuricosuria.

Standardization of the management of pediatric urolithiasis in the emergency department.

INTRODUCTION: The incidence of urolithiasis in the pediatric population is rising and medical expulsive therapy (MET) using alpha-adrenergic antagonists has been found to be effective in aiding in the passage of ureteral stones in children. A prior review of patients presenting to our quaternary children's hospital with urolithiasis found only 54 % were prescribed MET and these patients had increased rates of spontaneous stone passage. Thus, an ED urolithiasis management protocol was created to standardize evaluation and care of children with suspected urolithiasis. OBJECTIVE: To compare management of children with urolithiasis presenting to the ED before and after urolithiasis management protocol implementation. METHODS: This is a retrospective review of patients with urolithiasis who presented to our children's ED from 2011 to 2022. The primary outcome was rate of MET prescribing before and after pathway implementation in July 2017, thus the pre-implementation group comprises patients who presented to the ED from July 2011 to July 2017, and the post-protocol group includes those who presented from August 2017 to April 2022. Secondary outcomes included CT utilization in the ED, surgical intervention rate, proportion with spontaneous stone passage, and frequency of urology consultation. Two-sample t-test and Fisher's exact test were used to compare the outcomes of interest before and after protocol implementation. RESULTS: Of 337 patients who presented to the ED after protocol implementation, 120 met inclusion criteria. When comparing outcomes before and after implementation of the protocol, there was significantly decreased use of CT scans (79 % vs 50 %, p < 0.0001) and increased prescribing of MET (54 % vs 82 %, p < 0.0001). There was a significant decrease in opioids prescribed (44 % vs 26.7 %, p = 0.0040), and an increased rate of spontaneous stone passage (34 % vs 46 %, p = 0.0483). Lastly, there was a significant reduction in the rate of surgery for stone management after the implementation of protocol (35 % vs 17 %, p = 0.0020) DISCUSSION: As the ED is the primary site of presentation for many children with urolithiasis, standardization of evaluation and management provides an opportunity to improve outcomes in this population. We found that implementation of an ED urolithiasis management protocol was associated with decreased use of CT scans, decreased opioid prescribing, increased spontaneous stone passage, and decreased rate of surgical management for children with ureteral stones. CONCLUSIONS: This study demonstrates the positive impact of standardizing care for children presenting to the ED with urolithiasis.

Evaluating the performance of ChatGPT in answering questions related to urolithiasis.

PURPOSE: ChatGPT is an artificial intelligence (AI) program with natural language processing. We analyzed ChatGPT's knowledge about urolithiasis whether it can be used to inform patients about urolithiasis. METHODS: Frequently asked questions (FAQs) about urolithiasis on the websites of urological associations and hospitals were analyzed. Also, strong recommendation-level information was gathered from the urolithiasis section of the European Association of Urology (EAU) 2022 Guidelines. All questions were asked in order in ChatGPT August 3rd version. All answers were evaluated separately by two specialist urologists and scored between 1 and 4, where 1: completely correct, 2: correct but inadequate, 3: a mix of correct and misleading information, and 4: completely incorrect. RESULTS: Of the FAQs, 94.6% were answered completely correctly. No question was answered completely incorrectly. All questions about general, diagnosis, and ureteral stones were graded as 1. Of the 60 questions prepared according to the EAU guideline recommendations, 50 (83.3%) were evaluated as grade 1, and 8 (13.3%) and 2 (3.3%) as grade 3. All questions related to general, diagnostic, renal calculi, ureteral calculi, and metabolic evaluation received the same answer the second time they were asked. CONCLUSION: Our findings demonstrated that ChatGPT accurately and satisfactorily answered more than 95% of the questions about urolithiasis. We conclude that applying ChatGPT in urology clinics under the supervision of urologists can help patients and their families to have better understanding on urolithiasis diagnosis and treatment.

Simultaneous Detection of Citric Acid and Oxalic Acid Based on Dual Spectrum and Biomimetic Peroxidase for Urolithiasis Screening with a Fully Automatic Urine Analyzer.

Urolithiasis stands as a prevalent ailment within the urinary system, with hyperoxaluria and hypocitraturia being the most frequent manifestations characterized by excessive oxalic acid (OA) and deficient citric acid (CA) levels in urine. Detecting these compounds in urine quantitatively holds paramount importance for early urolithiasis screening. Existing methodologies fall short in achieving simultaneous and on-site identification of OA and CA, posing challenges for accurate urolithiasis screening. Addressing this concern, the study successfully accomplishes the concurrent identification of OA and CA in urine through a combination of dual-spectral analysis and biomimetic peroxidase utilization. Bovine serum albumin and dithiothreitol-modified copper nanoclusters (BSA-DTT-CuNCs) are employed as biomimetic peroxidases, effectively mitigating interference and enabling the simultaneous determination of OA and CA. The quantification range spans from 0 to 12 mm for OA and 0.5 to 2.5 mm for CA, with detection limits of 0.18 and 0.11 mm, respectively. To facilitate swift and on-location urine analysis, a fully automated urine analyzer (FAUA) is introduced that streamlines the process of biomarker pretreatment and identification within urine samples. Validation with real urine samples from urolithiasis patients demonstrates the method's diagnostic precision, highlighting the dual-spectral technique and analyzer's promising role in urolithiasis screening.

High risk and low prevalence diseases: Infected urolithiasis.

INTRODUCTION: Infected urolithiasis is a serious condition that carries with it a high rate of morbidity and mortality. OBJECTIVE: This review highlights the pearls and pitfalls of infected urolithiasis, including presentation, diagnosis, and management in the emergency department based on current evidence. DISCUSSION: Although urolithiasis is common and the vast majority can be treated conservatively, the presence of a concomitant urinary tract infection significantly increases the risk of morbidity, to include sepsis and mortality. Identification of infected urolithiasis can be challenging as patients may have symptoms similar to uncomplicated urolithiasis and/or pyelonephritis. However, clinicians should consider infected urolithiasis in toxic-appearing patients with fever, chills, dysuria, and costovertebral angle tenderness, especially in those with a history of recurrent urinary tract infections. Positive urine leukocyte esterase, nitrites, and pyuria in conjunction with an elevated white blood cell count may be helpful to identify infected urolithiasis. Patients should be resuscitated with fluids and broad-spectrum antibiotics. Additionally, computed tomography and early urology consultation are recommended to facilitate definitive care. CONCLUSIONS: An understanding of infected urolithiasis can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

2022 Recommendations of the AFU Lithiasis Committee: Epidemiology, stone analysis and composition.

The incidence of urinary lithiasis is rising steadily in industrialized countries, and its prevalence in the general population of France is estimated at 10%. Renal colic accounts for 1-2% of emergency department consultations. At a time when the new LASER stone fragmentation techniques available to urologists will lead to ever finer in situ pulverization of stones, the exact identification of the compounds that form the stone is essential for etiological diagnosis. Constitutional analysis by infrared spectrophotometry or X-ray diffraction is therefore recommended, to be complemented by morphological typing of the calculi. METHODOLOGY: These recommendations have been drawn up using two methods: the Recommendation for Clinical Practice (RPC) method and the ADAPTE method, depending on whether or not the issue was considered in the EAU recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Endoscopic description of renal papillae and stones.

Endoscopic observation is performed during treatments by flexible ureteroscopy to differentiate in situ between renal papillary abnormalities and stones based on their concordance with Daudon's morphological/composition descriptions adapted to endoscopy. These intraoperative visual analyses are now an integral part of the urinary stone disease diagnostic approach in addition to the morphological/structural and spectrophotometric analysis that remains the reference exam, but that loses information on the stone component representativeness due to the development of in situ laser lithotripsy. These are the first practical recommendations on the endoscopic description of renal papillae and stones. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations (CPR) and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU Guidelines on urolithiasis. 2022]) and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Management of symptomatic urinary stones.

The acute situation, caused by an obstructive stone, is defined by a renal colic that may be uncomplicated, complicated, or at risk in specific conditions. Its management may be medical or require interventional treatment by extracorporeal shockwave lithotripsy, endoscopic removal, or ureteroscopy. METHODOLOGY: These recommendations were developed using two methods, the Clinical Practice Recommendations (CPR) and the ADAPTE method, in function of whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and whether they could be adapted to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Specific cases - chronic kidney disease, bilateral stones, and solitary kidney.

Chronic kidney disease, diabetes and hypertension are risk factors of kidney function impairment. The relative risk of kidney failure is 1.52 in patients with urinary stone disease. The various techniques used to remove upper urinary tract stones generally do not alter kidney function in patients with normal kidney function and may sometimes improve kidney function or slow its deterioration in patients with kidney disease. Compared to the asynchronous treatment of bilateral renal and ureteral stones, concomitant treatment is associated with higher risk of anuria and the need of additional interventions, in the absence of postoperative stenting. For the treatment of solitary kidney stones, the absence of postoperative stenting increases the risk of postoperative anuria. Moreover, the multiplication of percutaneous nephrolithotomy access tracts increases the risk of bleeding and that of kidney function impairment. METHODOLOGY: These recommendations were developed according to two methods: the Clinical Practice Recommendations (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Medical management - from diagnosis to treatment.

The morphological-compositional analysis of urinary stones allows distinguishing schematically several situations: dietary, digestive, metabolic/hormonal, infectious and genetic problems. Blood and urine testing are recommended in the first instance to identify risk factors of urinary stone disease in order to avoid recurrence or progression. The other objective is to detect a potential underlying pathology associated with high risk of urinary stone disease (e.g. primary hyperparathyroidism, primary or enteric hyperoxaluria, cystinuria, distal renal tubular acidosis) that may require specific management. Lifestyle-diet measures are the basis of the management of all stone types, but pharmacological treatments may be required. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

REPRESENTATION OF KIDNEY DAMAGE AT THE MOLECULAR LEVEL IN PATIENTS WITH UROLITHIASIS BASED ON THE STUDY OF ENZYMATIC TEST INDICATORS.

The aim of the work is to improve the results of early diagnosis of acute infectious kidney diseases at the molecular level in urolithiasis (urinary stone disease) through the study of enzymatic test indicators. Enzymatic tests (NGAL, IL-1ß, ß2-microglobulin) were investigated at the molecular level using the IFA method in the urine of patients with urolithiasis. Comparative and prognostic significance of the conducted treatment was established between the groups of patients, and an algorithm was developed based on the results of kidney damage predictors. It was found that the indicators of general laboratory analysis in patients with urolithiasis within the first 24-48 hours do not reliably indicate the absence of an infectious-inflammatory process in the kidneys and the development of renal failure. It was determined that an increase in the inflammation predictor indicators in more than 50% of patients indicates the development of infectious-inflammatory complications within the first 12-24 hours before the occurrence of general laboratory and clinical changes. The assessment of the effectiveness of conservative therapy in groups IA and II revealed that complications of the inflammatory process in the kidneys were observed five times more frequently in group II (comparison) than in group IA. The use of enzymatic tests as markers for early kidney damage allows for the classification of two main groups of patients: those requiring conservative treatment and those requiring urgent surgical intervention. This significantly reduces the frequency of inflammatory, purulent-septic complications and improves the treatment outcomes for patients with upper urinary tract obstruction in urolithiasis.

Comprehensive prediction of urolithiasis based on clinical factors, blood chemistry and urinalysis: UROLITHIASIS score.

Comprehensive prediction of urolithiasis using available factors obtained in the emergency department may aid in patient-centered diagnostic imaging decisions. This retrospective study analyzed the clinical factors, blood chemistry and urine parameters of patients who underwent nonenhanced urinary computed tomography for suspected urolithiasis. A scoring system was developed from a logistic regression model and was tested using the area under the curve (AUC). The prevalence of urolithiasis and important possible causes in the three risk subgroups were determined. Finally, the scoring model was validated. In the derivation cohort (n = 673), 566 patients were diagnosed with urolithiasis. Age > 35 years, history of urolithiasis, pain duration < 8 h, nausea/vomiting, costovertebral angle tenderness, serum creatinine ≥ 0.92 mg/dL, erythrocytes ≥ 10/high power field, no leukocytes ≤ + , and any crystalluria were retained in the final multivariable model and became part of the score. This scoring model demonstrated good discrimination (AUC 0.808 [95% CI, 0.776-0.837]). In the validation cohort (n = 336), the performance was similar (AUC 0.803 [95% CI, 0.756-0.844]), surpassing that of the STONE score (AUC 0.654 [95% CI, 0.601-0.705], P < 0.001). This scoring model successfully stratified patients according to the probability of urolithiasis. Further validation in various settings is needed.

[Imaging for urolithiasis]. / Bildgebung bei Urolithiasis.

The substantial reduction of radiation exposure using (ultra-)low dose programs in native computed tomographic imaging has led to considerable changes in imaging diagnostics and treatment planning in urolithiasis in recent years. In addition, especially in Germany, ultrasound diagnostics is highly available in terms of equipment and with increasing expertise. This can largely replace the previous radiation-associated procedures in emergency and follow-up diagnostics, but also in intraoperative imaging, e.g., in percutaneous stone therapy (intraoperative fluoroscopy). This is reflected in the international guidelines, which recommend these two modalities as first-line diagnostics in all areas mentioned. Continuous technical development enables ever higher resolution imaging and thus improved diagnostics with high sensitivity and specificity. This also enables reliable imaging of particularly vulnerable patient groups, such as children or pregnant women. In addition, methods from the field of artificial intelligence (AI; machine learning, deep learning) are increasingly being used for automated stone detection and stone characterization including its composition. Furthermore, AI models can provide prognosis models as well as individually tailored treatment, follow-up, and prophyaxis. This will enable further personalization of diagnostics and therapy in the field of urolithiasis.

[Report template from the German Society of Urology and the German Radiological Society for standardized, structured reporting of native computed tomography scans in the diagnosis of urinary stones]. / Befundvorlage der Deutschen Gesellschaft für Urologie e. V. und der Deutschen Röntgengesellschaft zur standardisierten strukturierten Befundung von nativen Computertomographien in der Harnsteindiagnostik.

Standardized structured radiological reporting (SSRB) has been promoted in recent years. The aims of SSRB include that reports be complete, clear, understandable, and stringent. Repetitions or superfluous content should be avoided. In addition, there are advantages in the presentation of chronological sequences, tracking and correlations with structured findings from other disciplines and also the use of artificial intelligence (AI)-based methods. The development of the presented template for SSRB of native computed tomography for urinary stones followed the "process for the creation of quality-assured and consensus-based report templates as well as subsequent continuous quality control and updating" proposed by the German Radiological Society (DRG). This includes several stages of drafts, consensus meetings and further developments. The final version was published on the DRG website ( www.befundung.drg.de ). The template will be checked annually by the steering group and adjusted as necessary. The template contains 6 organ domains (e.g., right kidney) for which entries can be made for a total of 21 different items, mostly with selection windows. If "no evidence of stones" is selected for an organ in the first query, the query automatically jumps to the next organ, so that the processing can be processed very quickly despite the potentially high total number of individual queries for all organs. The German, European, and North American Radiological Societies perceive the establishment of a standardized structured diagnosis of tomographic imaging methods not only in oncological radiology as one of the current central tasks. With the present template for the description of computed tomographic findings for urinary stone diagnostics, we are presenting the first version of a urological template. Further templates for urological diseases are to follow.

[Epidemiology and diagnosis of urinary lithiasis: a cross-sectional study in a Cameroonian based population]. / Epidémiologie et diagnostic de la lithiase urinaire: étude transversale dans une population camerounaise.

Introduction: urinary stone is a multifactorial disease characterized by the presence of concretions in the urinary tract. The diagnosis of urinary lithiasis is based on clinical and imaging findings. The objective of this study was to determine the profile of patients suffering from urolithiasis in the city of Yaounde. Methods: this was a descriptive observational cross-sectional study with retrospective data collection. Patients with an age > 15 years and patients diagnosed with lithiasis confirmed by medical imaging were included in our study. The variables studied were sociodemographic, clinical and paraclinical. Results: a total of 120 patients were included in our study. The mean age was 40.46±12.62 years with extremes from 19 to 74 years. Male gender was predominant at 60.8% (n=73). Renal colic was the circumstance found in 67.5% (n=81). Physical examination was normal in 55.8% (n=67). Insufficient hydration was found in 45% (n=61) of cases. Abdominal scanner was the most performed examination in our study in 50.7% (n=61). The median stone density was 731 Hounsfield units [346; 1183.5]. The stones were predominantly located in the upper tract. The left renal topography was predominant in 35% (n=42) of cases. Urine culture revealed Escherichia Coli at 60% (n=15). Blood calcium, phosphorus and uricemia were requested in 15.8% (n=19), 0.8% (n=1) and 12.5% (n=15) of cases, respectively. The results were normal. In the absence of a laboratory specialized in biochemical analysis of calculi, a minority of patients (n=3) benefited from spectrophotometry. Conclusion: urinary lithiasis is a disease of men in their forties. Renal colic is the main revealing sign. The diagnosis is revealed by the abdominal scanner in half of the cases. Metabolic assessment and constitutional analysis of the calculus are still very rarely requested.

Adenine phosphoribosyl transferase (APRT) deficiency and a novel sequence variant in APRT with phenotypic diversity and a literature review.

Adenine phosphoribosyl transferase (APRT) deficiency is an autosomal recessive disorder and a rare cause of urolithiasis due to mutations in APRT (OMIM #102600). APRT deficiency results in increased urinary excretion of 2,8-dihydroxyadenine (DHA) which can cause urolithiasis and kidney failure. However, with prompt diagnosis, patients with APRT deficiency can be treated with xanthine oxidoreductase inhibitors which decrease urinary DHA excretion and improve outcomes. We report a pair of siblings, an 11-year-old brother and his 14-year-old sister with compound heterozygous variants c.270del (p.Lys91Serfs*46) and c.484_486del (p.Leu162del) in APRT with variable clinical presentation of APRT deficiency. The brother presented at 17 months of age with urolithiasis and severe acute kidney injury. His elder sister remained well and asymptomatic with normal kidney function and did not develop renal calculi. Brownish disk or sphere-like crystals with both concentric and radial markings were reported on urine microscopy in the sister on screening. The sister's diagnosis was confirmed with further laboratory evidence of absent red cell lysate APRT activity with corresponding elevated levels of urinary DHA. In conclusion, we identified a novel mutation in the APRT gene in a pair of siblings with greater phenotypic severity in the male.