Screening for asymptomatic nephrolithiasis in primary hyperparathyroidism patients is warranted

BACKGROUND

We aimed to investigate the prevalence, characteristics, and management of nephrolithiasis in primary hyperparathyroidism (PHPT) patients.

METHODS

Medical records of patients who underwent parathyroidectomy at a tertiary care hospital in British Columbia from January 2016 to April 2023 were retrospectively reviewed. Demographic data, laboratory results, imaging reports, and urologic consultations were examined. Descriptive statistics and relevant statistical tests, including logistic regressions, were utilized for data analysis.

RESULT

Of the 413 PHPT patients included in the study population, 41.9% harbored renal stones, and nearly half (48.6%) required urological interventions. Male sex, elevated preoperative serum ionized calcium (iCa) and 24-h urinary calcium (24 ​h urine Ca) levels were independent risk factors for stone formation. Additionally, male sex, younger age, and lower preoperative serum 25-hydroxyvitamin D (25(OH)D) level were associated with higher odds of requiring urological intervention for stones.

CONCLUSIONS

This study identified significant prevalence of asymptomatic renal calcifications in PHPT patients, with a substantial proportion necessitating urological intervention. These findings emphasize the importance of incorporating screening and treatment of renal stones into the management of PHPT patients.

Comprehensive evaluation of patients with primary hyperoxaluria type 1: A nationwide study

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is characterized by increased endogenous oxalate production and deposition as calcium oxalate crystals. The main manifestations are nephrocalcinosis/nephrolithiasis, causing impaired kidney function. We aimed to evaluate the clinical characteristics and overall outcomes of paediatric PH1 patients in Turkey.

METHODS

This is a nationwide, multicentre, retrospective study evaluating all available paediatric PH1 patients from 15 different paediatric nephrology centres in Turkey. Detailed patient data was collected which included demographic, clinical and laboratory features. Patients were classified according to their age and characteristics at presentation: patients presenting in the first year of life with nephrocalcinosis/nephrolithiasis (infantile oxalosis, Group 1), cases with recurrent nephrolithiasis diagnosed during childhood (childhood-onset PH1, Group 2), and asymptomatic children diagnosed with family screening (Group 3).

RESULTS

Forty-eight patients had a mutation consistent with PH1. The most common mutation was c.971_972delTG (25%). Infantile oxalosis patients had more advanced chronic kidney disease (CKD) or kidney failure necessitating dialysis (76.9% vs. 45.5%). These patients had much worse clinical course and mortality rates seemed to be higher (23.1% vs. 13.6%). Patients with fatal outcomes were the ones with significant comorbidities, especially with cardiovascular involvement. Patients in Group 3 were followed with better outcomes, with no kidney failure or mortality.

CONCLUSION

PH1 is not an isolated kidney disease but a systemic disease. Family screening helps to preserve kidney function and prevent systemic complications. Despite all efforts made with traditional treatment methods including transplantation, our results show devastating outcomes or mortality.

Machine learning models for screening clinically significant nephrolithiasis in overweight and obese populations

PURPOSES

Our aim is to build and evaluate models to screen for clinically significant nephrolithiasis in overweight and obesity populations using machine learning (ML) methodologies and simple health checkup clinical and urine parameters easily obtained in clinics.

METHODS

We developed ML models to screen for clinically significant nephrolithiasis (kidney stone > 2 mm) in overweight and obese populations (body mass index, BMI ≥ 25 kg/m2) using gender, age, BMI, gout, diabetes mellitus, estimated glomerular filtration rate, bacteriuria, urine pH, urine red blood cell counts, and urine specific gravity. The data were collected from hospitals in Kaohsiung, Taiwan between 2012 and 2021.

RESULTS

Of the 2928 subjects we enrolled, 1148 (39.21%) had clinically significant nephrolithiasis and 1780 (60.79%) did not. The testing dataset consisted of data collected from 574 subjects, 235 (40.94%) with clinically significant nephrolithiasis and 339 (59.06%) without. One model had a testing area under curve of 0.965 (95% CI, 0.9506-0.9794), a sensitivity of 0.860 (95% CI, 0.8152-0.9040), a specificity of 0.947 (95% CI, 0.9230-0.9708), a positive predictive value of 0.918 (95% CI, 0.8820-0.9544), and negative predictive value of 0.907 (95% CI, 0.8756-0.9371).

CONCLUSION

This ML-based model was found able to effectively distinguish the overweight and obese subjects with clinically significant nephrolithiasis from those without. We believe that such a model can serve as an easily accessible and reliable screening tool for nephrolithiasis in overweight and obesity populations and make possible early intervention such as lifestyle modifications and medication for prevention stone complications.

Genetic testing in children with nephrolithiasis and nephrocalcinosis

BACKGROUND

Diagnosing genetic kidney disease has become more accessible with low-cost, rapid genetic testing. The study objectives were to determine genetic testing diagnostic yield and examine predictors of genetic diagnosis in children with nephrolithiasis/nephrocalcinosis (NL/NC).

METHODS

This retrospective multicenter cross-sectional study was conducted on children ≤ 21 years old with NL/NC from pediatric nephrology/urology centers that underwent the Invitae Nephrolithiasis Panel 1/1/2019-9/30/2021. The diagnostic yield of the genetic panel was calculated. Bivariate and multiple logistic regression were performed to assess for predictors of positive genetic testing.

RESULTS

One hundred and thirteen children (83 NL, 30 NC) from 7 centers were included. Genetic testing was positive in 32% overall (29% NL, 40% NC) with definite diagnoses (had pathogenic variants alone) made in 11.5%, probable diagnoses (carried a combination of pathogenic variants and variants of uncertain significance (VUS) in the same gene) made in 5.4%, and possible diagnoses (had VUS alone) made in 15.0%. Variants were found in 28 genes (most commonly HOGA1 in NL, SLC34A3 in NC) and 20 different conditions were identified. Compared to NL, those with NC were younger and had a higher proportion with developmental delay, hypercalcemia, low serum bicarbonate, hypophosphatemia, and chronic kidney disease. In multivariate analysis, low serum bicarbonate was associated with increased odds of genetic diagnosis (β 2.2, OR 8.7, 95% CI 1.4-54.7, p = 0.02).

CONCLUSIONS

Genetic testing was high-yield with definite, probable, or possible explanatory variants found in up to one-third of children with NL/NC and shows promise to improve clinical practice. A higher resolution version of the Graphical abstract is available as Supplementary information.

Changes in practice patterns of nephrolithiasis in the era of the coronavirus disease 2019 pandemic: a review

PURPOSE OF REVIEW

The coronavirus disease 2019 (COVID-19) pandemic led to a drastic change in healthcare priorities, availability of resources and accommodation of different needs and scenarios. We sought to review the effect of the pandemic on different aspects of nephrolithiasis.

RECENT FINDINGS

The pandemic resulted in a significant impact on management of patients with nephrolithiasis around the world. A significant decrease in patient presentation and differences in strategies of management to truncate exposure and surgery time and expedite patient discharge deferring definitive management has been noted. Moreover, new safety measures such as COVID-19 PCR testing prior to surgery and limiting any intervention for COVID-19 positive patients to only life-saving scenarios has been implemented. Different emergency triaging proposals are being used, mainly including high risk patients with septic shock or complete obstruction/renal injury. Moreover, the emergence of telehealth has changed outpatient practice dramatically with a significant adoption to minimize exposure. Lastly, the effect of COVID-19 on renal physiology has been described with significant potential to cause morbidity from immediate or delayed acute kidney. No physiological effect on stone formation has yet been described, and transmission through urine is rare.

SUMMARY

The COVID-19 pandemic has markedly shifted the treatment of nephrolithiasis in many ways, including emergency triage, outpatient care, and definitive management. Although various approaches and algorithms proposed are meant to optimize management in the time of the pandemic, further studies are required for validation.

Development and validation of a nomogram for risk prediction of nephrolithiasis recurrence in patients with primary hyperparathyroidism

BACKGROUND

Nephrolithiasis is a common complication of primary hyperparathyroidism (PHPT), and the recurrence of nephrolithiasis in patients with PHPT is also an urgent concern. What is worse, there is a scarcity of recommended evaluation to predict the risk of nephrolithiasis recurrence in patients with PHPT. This study was aimed to develop and validate a nomogram to facilitate risk assessment in patients with PHPT.

METHODS

A total of 197 patients with PHPT were retrospectively included in this study from September 2016 to August 2021. Patients' demographic data, blood test parameters, urinalysis, stone parameters, and surgical intervention were collected. Extracted variables were submitted to a least absolute shrinkage and selection operator (LASSO) regression model. A nomogram was built and validated according to the area under the curve (AUC) value, calibration curve, and decision curve analysis.

RESULTS

According to the LASSO regression and logistic regression analyses, five predictors were derived from 22 variables: creatinine, uric acid, bilateral stone, multiplicity, and surgery. The AUC and concordance index of the training cohort and validation cohort were 0.829 and 0.856, and 0.827 and 0.877, respectively. The calibration curve analysis and the decision curve analysis showed that the nomogram had an adequate prediction accuracy.

CONCLUSION

We built a useful nomogram model to predict the risk of nephrolithiasis recurrence in patients with PHPT. This would assist clinicians to provide appropriate advices and managements for these patients.

Genotype Phenotype Correlation in Dent Disease 2 and Review of the Literature: OCRL Gene Pleiotropism or Extreme Phenotypic Variability of Lowe Syndrome?

Dent disease is a rare X-linked renal tubulopathy due to CLCN5 and OCRL (DD2) mutations. OCRL mutations also cause Lowe syndrome (LS) involving the eyes, brain and kidney. DD2 is frequently described as a mild form of LS because some patients may present with extra-renal symptoms (ESs). Since DD2 is a rare disease and there are a low number of reported cases, it is still unclear whether it has a clinical picture distinct from LS. We retrospectively analyzed the phenotype and genotype of our cohort of 35 DD2 males and reviewed all published DD2 cases. We analyzed the distribution of mutations along the OCRL gene and evaluated the type and frequency of ES according to the type of mutation and localization in OCRL protein domains. The frequency of patients with at least one ES was 39%. Muscle findings are the most common ES (52%), while ocular findings are less common (11%). Analysis of the distribution of mutations revealed (1) truncating mutations map in the PH and linker domain, while missense mutations map in the 5-phosphatase domain, and only occasionally in the ASH-RhoGAP module; (2) five OCRL mutations cause both DD2 and LS phenotypes; (3) codon 318 is a DD2 mutational hot spot; (4) a correlation was found between the presence of ES and the position of the mutations along OCRL domains. DD2 is distinct from LS. The mutation site and the mutation type largely determine the DD2 phenotype.

Abdominal Pain in the Emergency Department: Missed Diagnoses

Abdominal pain is the most common chief complaint in the Emergency Department. Abdominal pain is caused by a variety of gastrointestinal and nongastrointestinal disorders. Some frequently missed conditions include biliary pathology, appendicitis, diverticulitis, and urogenital pathology. The Emergency Medicine clinician must consider all aspects of the patient's presentation including history, physical examination, laboratory testing, and imaging. If no diagnosis is identified, close reassessment of pain, vital signs, and physical examination are necessary to ensure safe discharge. Strict verbal and written return precautions should be provided to the patient.

Stones left unturned: Missed opportunities to diagnose primary hyperparathyroidism in patients with nephrolithiasis

BACKGROUND

Nephrolithiasis is a sequela of primary hyperparathyroidism and an indication for parathyroidectomy. The prevalence of primary hyperparathyroidism in patients with nephrolithiasis is 3% to 5%; however, recent studies suggest that many hypercalcemic patients with nephrolithiasis never undergo workup for primary hyperparathyroidism. Our goal is to evaluate primary hyperparathyroidism screening rates at a tertiary academic health institution and identify opportunities to increase referral rates in patients presenting with nephrolithiasis.

METHODS

We retrospectively reviewed 15,725 patients across an academic health system who presented with nephrolithiasis between 2012 and 2020. Calcium levels measured within 6 months of presentation were identified, and those with hypercalcemia (≥10.3 mg/dL) were reviewed if parathyroid hormone levels were measured. Patients with primary hyperparathyroidism were evaluated to see if they were referred to a specialist for treatment.

RESULTS

Of 15,725 patients presenting with nephrolithiasis, 12,420 (79%) had calcium levels measured; 630 patients (4.0%) were hypercalcemic, and 207 (33%) had parathyroid hormone levels measured. Patients were more likely to have parathyroid hormone levels sent if they were older, had higher calcium levels, or presented to an outpatient clinic (P = .028, P = .002, P < .001). We identified 89 patients (0.6%) with primary hyperparathyroidism, of which only 35 (39%) were referred for treatment.

CONCLUSION

The proportion of patients presenting with nephrolithiasis ultimately diagnosed with primary hyperparathyroidism was significantly lower than others have reported. Additionally, a substantial number of patients with nephrolithiasis did not have calcium and/or parathyroid hormone levels measured. These missed opportunities for diagnosis are critical as early definitive management of primary hyperparathyroidism can prevent recurrent nephrolithiasis and other primary hyperparathyroidism-related end organ effects.

Use of prescription drug monitoring program to audit opioid prescribing patterns for patients with symptomatic nephrolithiasis

INTRODUCTION The opioid epidemic is a growing problem in the United States. There is a high rate of opioid oversupply for treatment of symptomatic nephrolithiasis, partly due to patients being seen by multiple providers. In Pennsylvania, there are efforts to integrate a prescription drug monitoring program (PDMP) within the electronic medical record (EMR). The objectives of this study were to evaluate prescribing practices for opioids for symptomatic nephrolithiasis and the incidence of prescriptions not documented within the EMR.

MATERIALS AND METHODS

Adults who presented for treatment of symptomatic nephrolithiasis were sequentially evaluated from May - October 2017 at Penn State Milton S. Hershey Medical Center. With IRB approval, we evaluated opioids prescribed in the EMR, which was compared to the PDMP for each stone episode. We calculated daily morphine milligram equivalents (MME) and total MME available to patients.

RESULTS

A total of 301 patients were identified (52% male) with a mean age of 50.0 +/- 16.7 years and 249 (83%) of patients were prescribed narcotics with an average of 226.8 +/- 232.2 MME for their stone episode. Of patients that were prescribed narcotics, 19% had additional narcotics prescribed to them that were not entered into the EMR and later identified using PDMP. The average additional opioid prescribed was 371.8 +/- 404.2 total MME.

CONCLUSIONS

The majority of patients presenting with symptomatic nephrolithiasis were prescribed an opioid. Approximately one-fifth of patients were receiving opioids from other providers that were not documented in the EMR at the time of their opioid prescription. PDMP, or similar resources, should be utilized by providers to minimize opioid use and reduce oversupplying patients.

The Impact of Dietary Modifications and Medical Management on 24-Hour Urinary Metabolic Profiles and the Status of Renal Stone Disease in Recurrent Stone Formers

BACKGROUND

Dietary modifications and patient-tailored medical management are significant in controlling renal stone disease. Nevertheless, the literature regarding effectiveness is sparse.

OBJECTIVES

To explore the impact of dietary modifications and medical management on 24-hour urinary metabolic profiles (UMP) and renal stone status in recurrent kidney stone formers.

METHODS

We reviewed our prospective registry database of patients treated for nephrolithiasis. Data included age, sex, 24-hour UMP, and stone burden before treatment. Under individual treatment, patients were followed at 6-8 month intervals with repeat 24-hour UMP and radiographic images. Nephrolithiasis-related events (e.g., surgery, renal colic) were also recorded. We included patients with established long-term follow-up prior to the initiation of designated treatment, comparing individual nephrolithiasis status before and after treatment initiation.

RESULTS

Inclusion criteria were met by 44 patients. Median age at treatment start was 60.5 (50.2-70.2) years. Male:Female ratio was 3.9:1. Median follow-up was 10 (6-25) years and 5 (3-6) years before and after initiation of medical and dietary treatment, respectively. Metabolic abnormalities detected included: hypocitraturia (95.5%), low urine volume (56.8%), hypercalciuria (45.5%), hyperoxaluria (40.9%), and hyperuricosuria (13.6%). Repeat 24-hour UMP under appropriate diet and medical treatment revealed a progressive increase in citrate levels compared to baseline and significantly decreased calcium levels (P = 0.001 and 0.03, respectively). A significant decrease was observed in stone burden (P = 0.001) and overall nephrolithiasis-related events.

CONCLUSIONS

Dietary modifications and medical management significantly aid in correcting urinary metabolic abnormalities. Consequently, reduced nehprolithiasis-related events and better stone burden control is expected.

Hypomagnesuria is Associated With Nephrolithiasis in Patients With Asymptomatic Primary Hyperparathyroidism

CONTEXT

The pathogenesis of nephrolithiasis in primary hyperparathyroidism (PHPT) remains to be elucidated. The latest guidelines suggest parathyroidectomy in patients with asymptomatic PHPT with hypercalciuria (> 400 mg/d) and increased stone risk profile.

OBJECTIVE

The objective of this work is to evaluate the association of urinary stone risk factors and nephrolithiasis in patients with asymptomatic sporadic PHPT and its clinical relevance.

DESIGN

A total of 157 consecutive patients with sporadic asymptomatic PHPT were evaluated by measurement of serum and 24-hour urinary parameters and kidney ultrasound.

RESULTS

Urinary parameters were tested in the univariate analysis as continuous and categorical variables. Only hypercalciuria and hypomagnesuria were significantly associated with nephrolithiasis in the univariate and multivariate analysis adjusted for age, sex, body mass index, estimated glomerular filtration rate, parathyroid hormone, 25-hydroxyvitamin D, serum calcium, and urine volume (odds ratio, OR 2.14 [1.10-4.56]; P = .04; OR 3.06 [1.26-7.43]; P = .013, respectively). Hypomagnesuria remained associated with nephrolithiasis in the multivariate analysis (OR 6.09 [1.57-23.5], P = .009) even when the analysis was limited to patients without concomitant hypercalciuria. The urinary calcium/magnesium (Ca/Mg) ratio was also associated with nephrolithiasis (univariate OR 1.62 [1.27-2.08]; P = .001 and multivariate analysis OR 1.74 [1.25-2.42], P = .001). Hypomagnesuria and urinary Ca/Mg ratio had a better, but rather low, positive predictive value compared with hypercalciuria.

CONCLUSIONS

Hypomagnesuria and urinary Ca/Mg ratio are each associated with silent nephrolithiasis and have potential clinical utility as risk factors, besides hypercalciuria, for kidney stones in asymptomatic PHPT patients. The other urinary indices that have been commonly thought to be associated with kidney stones in PHPT are not supported by our results.

Pediatric Nephrolithiasis: Risk Factors, Evaluation, and Prevention

Pediatric nephrolithiasis is a disease of increasing prevalence and economic burden, with data showing a rising trend among girls and adolescents. Kidney stones in children tend to have a high recurrence rate related to underlying risk factors, and the aim of evaluation should be to understand such causes so that targeted therapy can be provided to decrease recurrence and complications. Metabolic, anatomic, and genetic abnormalities as well as environmental risk factors have all been implicated in the pathogenesis of nephrolithiasis. Recent studies have focused on identifying monogenic causes of nephrolithiasis and/or nephrocalcinosis in young patients that would result in personalization of treatment as well as future diagnostic implications for family members. Treatment aims to decrease stone burden and recurrence as well as minimize complications and is guided by stone size and location as well as surgical expertise. Multidisciplinary care for these patients has been on the rise to provide a more comprehensive medical and surgical support. [Pediatr Ann. 2020;49(6):e262-e267.].

Two case reports of novel syndrome of bizarre performance of gastrointestinal endoscopy due to toxic encephalopathy of endoscopists among 181767 endoscopies in a 13-year-university hospital review: Endoscopists, first do no harm!

BACKGROUND

Although deficient procedures performed by impaired physicians have been reported for many specialists, such as surgeons and anesthesiologists, systematic literature review failed to reveal any reported cases of deficient endoscopies performed by gastroenterologists due to toxic encephalopathy. Yet gastroenterologists, like any individual, can rarely suffer acute-changes-in-mental-status from medical disorders, and these disorders may first manifest while performing gastrointestinal endoscopy because endoscopy comprises so much of their workday.

CASE SUMMARIES

Among 181767 endoscopies performed by gastroenterologists at William-Beaumont-Hospital at Royal-Oak, two endoscopies were performed by normally highly qualified endoscopists who manifested bizarre endoscopic interpretation and technique during these endoscopies due to toxic encephalopathy. Case-1-endoscopist repeatedly insisted that gastric polyps were colonic polyps, and absurdly “pressed” endoscopic steering dials to “take” endoscopic photographs; Case-2-endoscopist repeatedly insisted that had intubated duodenum when intubating antrum, and wildly turned steering dials and bumped endoscopic tip forcefully against antral wall. Endoscopy nurses recognized endoscopists as impaired and informed endoscopy-unit-nurse-manager. She called Chief-of-Gastroenterology who advised endoscopists to terminate their esophagogastroduodenoscopies (fulfilling ethical imperative of “physician, first-do-no-harm”), and go to emergency room for medical evaluation. Both endoscopists complied. In-hospital-work-up revealed toxic encephalopathy in both from: case-1-urosepsis and left-ureteral-impacted-nephrolithiasis; and case-2-dehydration and accidental ingestion of suspected illicit drug given by unidentified stranger. Endoscopists rapidly recovered with medical therapy.

CONCLUSION

This rare syndrome (0.0011% of endoscopies) may manifest abruptly as bizarre endoscopic interpretation and technique due to impairment of endoscopists by toxic encephalopathy. Recommended management (followed in both cases): 1-recognize incident as medical emergency demanding immediate action to prevent iatrogenic patient injury; 2- inform Chief-of-Gastroenterology; and 3-immediately intervene to abort endoscopy to protect patient. Syndromic features require further study.

Predictors of Nephrolithiasis, Osteoporosis, and Mortality in Primary Hyperparathyroidism

CONTEXT

Primary hyperparathyroidism (PHPT) has a prevalence of 0.86% and is associated with increased risk of nephrolithiasis and osteoporosis. PHPT may also be associated with increased risk of cardiovascular disease and mortality.

OBJECTIVE

To identify risk factors for nephrolithiasis, osteoporosis, and mortality in PHPT.

DESIGN

Retrospective cohort study.

SETTING

University teaching hospital.

PATIENTS

Presented with PHPT between 2006 and 2014 (n = 611).

MAIN OUTCOME MEASURE

Assessment of nephrolithiasis, osteoporosis, and mortality.

RESULTS

Of patients with PHPT, 13.9% had nephrolithiasis. Most had previously documented stone disease, and only 4.7% of asymptomatic patients who were screened for renal stones had calculi identified, not very dissimilar to the rate in the non-PHPT population. Younger age (P < 0.001) and male sex (P = 0.003) were the only independent predictors of nephrolithiasis. Of patients with dual-energy X-ray absorptiometry data, 48.4% had osteoporosis (223/461). Older age (P < 0.001), lower body mass index (P = 0.002), and lower creatinine (P = 0.006) were independently associated with a diagnosis of osteoporosis. Higher PTH was independently associated with lower z score at the hip (P = 0.009); otherwise, calcium and PTH were not associated with lower z scores. Mortality in PHPT was associated with older age (P < 0.008), social deprivation (P = 0.028), and adjusted calcium (P = 0.009) but not independently with PTH at diagnosis.

CONCLUSIONS

Screening for nephrolithiasis has a low yield, particularly in lower risk patients. Osteoporosis is only minimally associated with biochemical indices of PHPT. Mortality is associated with higher calcium (and possibly vitamin D deficiency) but not PTH.

Prevalence of low molecular weight proteinuria and Dent disease 1 CLCN5 mutations in proteinuric cohorts

BACKGROUND

Dent disease type 1 (DD1) is a rare X-linked disorder caused mainly by CLCN5 mutations. Patients may present with nephrotic-range proteinuria leading to erroneous diagnosis of focal segmental glomerulosclerosis (FSGS) and unnecessary immunosuppressive treatments.

METHODS

The following cohorts were screened for CLCN5 mutations: Chronic Kidney Disease in Children (CKiD; n = 112); Multicenter FSGS-Clinical Trial (FSGS-CT) (n = 96), and Novel Therapies for Resistant FSGS Trial (FONT) (n = 30). Urinary α₁-microglobulin (α₁M), albumin (A), total protein (TP), and creatinine (Cr) were assessed from CKiD subjects (n = 104); DD1 patients (n = 14); and DD1 carriers (DC; n = 8). TP/Cr, α₁M/Cr, α₁M/TP, and A/TP from the CKiD cohort were compared with DD1 and DC.

RESULTS

No CLCN5 mutations were detected. TP/Cr was lower in DC and CKiD with tubulointerstitial disease than in DD1 and CKiD with glomerular disease (p < 0.002). α₁M/Cr was higher in DD1 than in CKiD and DC (p < 0.001). A/TP was lower in DD1, DC, and CKiD with tubulointerstitial disease and higher in CKiD with glomerular disease (p < 0.001). Thresholds for A/TP of ≤ 0.21 and α₁M/Cr of ≥ 120 mg/g (> 13.6 mg/mmol) creatinine were good screens for Dent disease.

CONCLUSIONS

CLCN5 mutations were not seen in screened CKiD/FSGS cohorts. In our study, a cutoff of TP/Cr > 600 mg/g (> 68 mg/mmol) and A/TP of < 0.3 had a high sensitivity and specificity to distinguish DD1 from both CKiD glomerular and tubulointerstitial cohorts. α₁M/Cr ≥ 120 mg/g (> 13.6 mg/mmol) had the highest sensitivity and specificity when differentiating DD1 and studied CKiD populations.

Net Acid Excretion and Urinary Organic Anions in Idiopathic Uric Acid Nephrolithiasis

BACKGROUND AND OBJECTIVES

Idiopathic uric acid nephrolithiasis, which is closely associated with obesity and the metabolic syndrome, is increasing in prevalence. Unduly acidic urine pH, the quintessential pathophysiologic feature of this disease, is in part explained by inadequate excretion of the principal urinary buffer ammonium. The role of net acid excretion in the pathogenesis of uric acid nephrolithiasis is incompletely understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We compared acid-base parameters of patients with idiopathic uric acid nephrolithiasis with matched control subjects under controlled diets in an inpatient metabolic unit. Measurements included fasting blood and 24-hour urine chemistries and 24-hour urine metabolomic analysis. Comparisons between groups included analysis of covariance models controlling for urine pH or body mass index.

RESULTS

Subjects with idiopathic uric acid nephrolithiasis had lower urine pH (5.5 versus 5.9; P<0.001) and higher net acid excretion (60 versus 43 mEq/24 h; P<0.001), with the excess H+ carried by nonammonium buffers. In all subjects, there was a positive relationship of net acid excretion with higher body mass index in spite of strictly controlled equivalent dietary acid intake. This relationship was most evident among control subjects (r=0.36; P=0.03). It was attenuated in patients with idiopathic uric acid nephrolithiasis whose net acid excretion remained fixedly high and ammonium excretion remained low relative to net acid excretion, resulting in low urine pH over a wide body mass index range. Urinary metabolomics was performed to attempt to identify excess organic acids presented to the kidney in idiopathic uric acid nephrolithiasis. Among the tricarboxylic acid cycle intermediates and amino acid and lipid metabolites analyzed, 26 organic anions with acid dissociation constants values in the range of urine pH showed greater protonation. However, protons carried by the identified organic acids did not entirely account for the higher titratable acidity seen in idiopathic uric acid nephrolithiasis.

CONCLUSIONS

Higher acid load to the kidney, resulting in higher urinary net acid excretion, is an important factor in the pathogenesis of idiopathic uric acid nephrolithiasis.

Can urine osteopontin levels, which may be correlated with nutrition intake and body composition, be used as a new biomarker in the diagnosis of nephrolithiasis?

BACKGROUND AND AIM

The nephrolithiasis has a multifactorial etiology resulting from the interaction of metabolic, genetic and environmental factors. Parameters such as nutrition and urinary osteopontin (OPN) level may affect kidney stone formation. The purpose of this study is to evaluate the correlation between urinary OPN level and kidney stone formation and effect of nutrition on OPN level in nephrolithiasis.

MATERIALS AND METHODS

This study was conducted on 88 volunteers including 44 healthy individuals and 44 patients diagnosed with nephrolithiasis and aging between 20 and 65 years. Some serum parameters and urinary OPN levels of the individuals were analyzed. Several anthropometric measurements of the individuals were taken and calculated their body mass index. Additionally, 24-hour dietary recall and water intakes were recorded and the participants completed food-frequency questionnaire for the evaluation of their nutritional status.

RESULTS

Urinary OPN (ng/mL) levels of patients were lower than that of control group (p<0.05). Dietary energy, carbohydrate, poly-unsaturated fatty acid (PUFA) and n-6 fatty acids intakes and urinary OPN levels of male patients were positively correlated (p<0.05). Additionally, there was a negative correlation between their urinary OPN (ng/mL) and serum creatinine (mg/dL) levels of female patients (p<0.05). Body weight, waist circumference, hip circumference and body muscle mass values of healthy males were positively correlated with their urinary OPN levels (p<0.05).

CONCLUSIONS

Results of the study showed that low urinary OPN levels were correlated with increased kidney stone risk, and dietary habits can affect urinary OPN level.

Urologic Emergencies

Urologic emergencies can involve the kidneys, ureters, bladder, urethra, penis, scrotum, or testicles. History and physical examination are essential to diagnosis, whereas imaging is increasingly used to confirm diagnoses. Acute urinary retention should be relieved with Foley placement. Penile emergencies include paraphimosis, which can be treated by foreskin reduction, whereas penile fracture and priapism require urologic intervention. Fournier gangrene and testicular torsion are scrotal emergencies requiring emergent surgery. Nephrolithiasis, although painful, is not an emergency unless there is concern for concomitant urinary tract infection, both ureters are obstructed by stones, or there is an obstructing stone in a solitary kidney.

Study of Urine Composition of Patients With Recurrent Nephrolithiasis in Lorestan, Iran

INTRODUCTION

Nephrolithiasis is one of the most common urinary tract diseases. After the first episode of urinary calculus, the risk of recurrence is nearly 40% to 50% at 5 years. Nephrolithiasis is a systemic disease that is associated with some metabolic disorders. This study aimed to provide a picture of the frequency of metabolic abnormalities in patients with nephrolithiasis from west part of Iran.

MATERIALS AND METHODS

Patients with recurrent urinary tract calculi referred to the Nephrology-Urology Clinics in Khorramabad city were recruited. After collection of demographic data of all the patients, 24-hour urine and blood samples were taken to measure biochemical factors.

RESULTS

Of the 232 participants, 125 were males and 107 were females. Hyperoxaluria was seen in 93 (40.1%) of the participants, hypercalciuria in 55 (23.7%), hypocitraturia in 58 (25%), and hyperuricosuria in 33 (14.9%). Hyperoxaluria in the males was significantly more frequent than in the female patients. There were no significant differences between the two groups in other urinary metabolic disorders.

CONCLUSIONS

Patients with nephrolithiasis from Lorestan province may have metabolic characteristics varying from those of regions; ethnicity may be a possible reason. Variation of dietary regimens, such as the amount of meat or vegetable in the diet that can change oxalate, calcium, or citrate of urine, might have influenced the results. Time of sampling is another factor. Population-specific studies are helpful to health care providers for preventive planning for nephrolithiasis.

Incidental Detection of Dent-2 Disease in an Infant with Febrile Proteinuria

OBJECTIVE

Febrile proteinuria is functional proteinuria and is seen as a transitory phenomenon during acute febrile illness, mainly viral infections. It is a benign phenomenon and clears promptly with resolution of the infection.

CLINICAL PRESENTATION AND INTERVENTION

In this report, we present a patient who was thought to have febrile proteinuria. Persistence of significant proteinuria after resolution of the infection prompted biochemical and genetic workup which led to the diagnosis of Dent-2 disease.

CONCLUSION

We recommend the use of SDS-PAGE (sodium dodecyl sulfate electropheresis) for the detection of low molecular weight proteinuria.

[Idiopathic hypercalciuria. Diagnosis and treatment]

Most patients with idiopathic hypercalciuria and calcium nephrolithiasis have a family history of the disease. Idiopathic hypercalciuria is a metabolic abnormality with various causes and developmental pathways. The systematic review describes specific mutations associated with idiopathic hypercalciuria and nephrolithiasis. Detection of these mutations may provide a better understanding of the pathogenesis of this heterogeneous disease and personalize patient management depending on the detected polymorphisms. A promising treatment option for a mutation in the vitamin D receptor gene is thiazide diuretics in combination with bisphosphonates. Among bisphosphonates, the drug of choice which has been most strongly supported by research evidence is alendronate.

Contemporary Management of Renal Transplant Recipients With De Novo Urolithiasis: A Single Institution Experience and Review of the Literature

OBJECTIVES

We report on the long-term follow-up of managing allograft stones at a single tertiary referral institution and review the relevant literature.

MATERIALS AND METHODS

A retrospective analysis of renal allograft recipient charts was performed to identify patients who developed allograft lithiasis between 1974 and 2009. Patient and stone characteristics, diagnoses, treatments, and outcomes were described.

RESULTS

Sixteen patients developed 22 stones after a median follow-up of 170 months (range, 51-351 mo). The mean (standard deviation) and median diameter of the stones were 13.8 (8.5) mm and 11 mm. Among these, 3 stones were treated conservatively, 3 by shock-wave lithotripsy, and 7 by cystolitholapaxy. Seven patients underwent percutaneous treatment in the form of percutaneous nephrostomy tube fixation and spontaneous passage of stone (1 stone), shock-wave lithotripsy (1 stone), antegrade stenting (1 stone), and percutaneous nephrolithotomy (6 stones). All patients were stone free after treatment, except for 2 patients whose stones were stable and peripheral on long-term follow-up.

CONCLUSIONS

Allograft lithiasis requires a multimodal treatment tailored according to stone and graft characteristics. Protocols regarding spontaneous passage can be adopted if there is no harm to the graft and the patient is compliant. Careful attention to the anatomy during percutaneous nephrostomy tube placement is mandatory to avoid intestinal loop injury. A more attentive follow-up is required for early stone management.

Phenotypic variability of Dent disease in a large New Zealand kindred

BACKGROUND

Dent disease 1 is a rare cause of chronic kidney disease (CKD) in childhood secondary to mutations in the gene encoding the chloride-proton exchanger, CLC-5, which is found mainly in the proximal tubule. Clinical manifestations are variable and there are no known genotype-phenotype correlations.

CASE DIAGNOSIS/TREATMENT

The proband was identified as having a mutation in CLCN5. The extended family of the proband was invited to participate in a study of Dent disease after several males were noted to have a history of CKD. Urine retinol binding protein, urine calcium, serum creatinine, and DNA samples were collected for analysis. Ten hemizygous males and 6 heterozygous females were identified. Advanced CKD was detected in 3 males (1 child). Renal biopsies in 4 children showed both glomerular and tubulo-interstitial changes. There was no correlation between age and disease severity.

CONCLUSIONS

This is the first reported family from the southern hemisphere with this condition. A novel CLCN5 mutation is described, c.1618G>C (p.Ala540Pro). The severity of renal disease varies greatly among individuals.

Clinical effectiveness in the diagnosis and acute management of pediatric nephrolithiasis

The incidence of pediatric nephrolithiasis has risen over the past few decades leading to a growing public health burden. Children and adolescents represent a unique patient population secondary to their higher risks from radiation exposure as compared to adults, high risk of recurrence, and longer follow up time given their longer life expectancies. Ultrasound imaging is the first-line modality for diagnosing suspected nephrolithiasis in children. Although data is limited, the best evidence based medicine supports the use of alpha-blockers as first-line MET in children, especially when stones are small and in a more distal ureteral location. Surgical management of pediatric nephrolithiasis is similar to that in adults with ESWL and URS first-line for smaller stones and PCNL reserved for larger renal stone burden. Clinical effectiveness in minimizing risks in children and adolescents with nephrolithiasis centers around ED pathways that limit CT imaging, strict guidance to ALARA principles or use of US during surgical procedures, and education of both patients and families on the risks of repeat ionizing radiation exposures during follow up and acute colic events.

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

BACKGROUND

Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research.

DESIGN

A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved.

RESULTS

Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients.

CONCLUSIONS

This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.

Recurrent nephrolithiasis associated with keratinizing desquamative squamous metaplasia

Keratinizing desquamative squamous metaplasia (KDSM) in the renal pelvis is a rare condition with unclear malignant potential. Recent reports suggest it is likely benign and favor endoscopic treatment approaches. Medical record review was completed on two cases at our center to obtain history, physical examination, radiographic findings, and management. A literature review was completed to identify all published cases of KDSM. Both patients at our center suffered recurrent urolithiasis, hypothesized to be secondary to KDSM. Both were managed with a percutaneous approach to ensure complete stone and KDSM plaque removal. Our cases highlight that percutaneous surgery is an excellent management option for stone and KDSM eradication from the collecting system. This approach also allows adequate oncologic surveillance of the underlying urothelium.

Pyelocystostomy for treatment of recurrent nephrolithiasis and ureteropelvic junction obstruction in a pelvic kidney

Patients with pelvic kidneys are at an increased risk of developing ureteropelvic junction obstruction (UPJO) and nephrolithiasis with limited endourologic options. A 54-year-old man with a left pelvic kidney, recurrent nephrolithiasis, and 12 previous ureteroscopies presented with left UPJO and lower pole calyceal stones. After two failed ureteroscopic attempts, an open pyelolithotomy and pyelocystostomy were performed. After 30 months, he continues to be asymptomatic without recurrence of nephrolithiasis. This constitutes the fifth such reported case. Therefore, pyelocystotomy is a good option for patients with pelvic kidneys, UPJO and recurrent nephrolithiasis refractory to endourologic procedures.

Evidence for epistatic interaction between VDR and SLC13A2 genes in the pathogenesis of hypocitraturia in recurrent calcium oxalate stone formers

BACKGROUND

Genetic factors play a key role in the pathogenesis of hypocitraturia, a common risk factor for nephrolithiasis. The Na⁺-dicarboxylate cotransporter NaDC1, encoded by the sodium-dicarboxylate cotransporter (SLC13A2) gene, is a major determinant of urinary citrate excretion and its biological functions are regulated also by the vitamin D/Vitamin D receptor (VDR) biological system. The aim of this case-control study was to evaluate the possible epistatic interaction between VDR ^rs731236and SLC13A2 ^rs11567842 allelic variants in the pathogenesis of hypocitraturia.

METHODS

Recurrent calcium-oxalate stone formers (SF) with or without hypocitraturia and healthy controls (C) were genotyped. Gene-gene interactions were estimated by the 1.0 software package of multifactor dimensionality reduction (MDR).

RESULTS

The prevalence of VDR ^TT and SLC13A2 ^GG genotypes was higher in hypocitraturic SF compared to C (odds ratio [OR] 3.24, 95 % confidence interval [CI] 1.38-7.60 for VDR ^TT vs. VDR ^tt and OR 4.06, 95 % CI 1.75-9.42 for SLC13A2 ^GG vs. SLC13A2 ^AA ). MDR analysis indicated a significant interaction between VDR ^TT and SLC13A2 ^GG in hypocitraturic SF compared to C [OR 3.81 (2.11-6.88)]. These data are compatible with an epistatic interaction between the VDR ^TT and SLC13A2 ^GG genotypes with a significant impact on the magnitude of the effect (suppressive effect).

CONCLUSIONS

These results point to an epistatic interaction between the VDR and the SLC13A2 alleles in the pathogenesis of idiopathic hypocitraturia in calcium-oxalate SF.

Is RIRS emerging as the preferred option for the management of 2 cm-4 cm renal stones: our experience

INTRODUCTION

The European Association of Urology (EAU) and the American Urological Association (AUA) guidelines recommend percutaneous nephrolithotomy (PCNL) as the first-line treatment of renal stones greater than 20 mm, however multistage retrograde intrarenal stone surgery (RIRS) is reported to have high stone-free rates (SFR), fewer complications and a rapid learning curve. This study presents our experience of RIRS in the management of 2 cm-4 cm renal stones.

MATERIALS AND METHODS

A retrospective study was performed of all patients who underwent RIRS for 2 cm-4 cm renal stones over a period of 22 months. The demographics of 71 patients as well as the stone and procedural demographics were recorded. Pre and postoperative radiological assessment was performed by NCCT scanning in 83% of the patients and ureteral access sheaths were used in only 12% of the patients. The severity of surgical complications was determined according to the Clavien-Dindo system.

RESULTS

RIRS was performed on 71 patients for renal stones with a mean size of 26 mm. The mean number of procedures per patient was 2.1 and the overall SFR was 81%. Few complications were encountered and only 1 patient had III-b Clavien complication.

CONCLUSION

The study further supports RIRS as a safe and efficacious treatment option for renal stones of 2 cm-4 cm in size. Although both the EAU and AUA do not currently recommend RIRS as the first-line treatment of such stones, it appears to be emerging as a commonly utilized primary modality.

[Cystinic nephrolythiasis: clinical experience and new diagnostic and therapeutic perspectives]

Cystinuria is an inherited autosomal recessive disease with a prevalence 1:7000 and typical age of onset in the second decade of life. This nephrolithiasis is not always well known and well studied and for this reason it is often underdiagnosed. Cystinuria is characterized by increased urinary excretion of cystine and dibasic amino acids (lysine, ornithine, arginine) caused by defective transport of these amino acids across the luminal membrane of proximal tubule and small intestine cells. Two mutated genes responsible of this tubular defect are SLC3A1 on chromosome 2 and SLC7A9 on chromosome 19. Clinical manifestations of cystinuria are essentially those related to stones formation and their movement across the urinary tract, like flank pain/abdomen pain and hematuria, as occurred in other nephrolithiasis types. Diagnosis is based on biochemical urine analysis, stone analysis and imaging. Genetic study of this disease may be a new and stimulating approach to better understand the defects and identify new therapeutic targets. A wider knowledge and a more detailed approach to cystinuria may help to ameliorate patients quality of life, to prevent recurrences and complications and to develop more specific and adequate treatments.

A Case of Solitary Kidney Atrophy Due to Primary Hyperparathyroidism: A Case Report

Although primary hyperparathyroidism (PHPT) is asymptomatic in most patients, its main clinical manifestation is nephrolithiasis. In general, hypercalcemia would lead to unilateral renal stones, which may become bilateral over time. We present a rare case of a large unilateral asymptomatic ureteral stone in a patient with hypercalcemia secondary to PHPT, which eventually led to renal atrophy.The diagnosis of PHPT should be considered in patients with hypercalcemia and renal stones, as asymptomatic PHPT may result in a devastating renal outcome.

[3D-TECHNOLOGY AS AN ELEMENT OF PLANNING, EFFECTIVE IMPLEMENTATION AND SURGICAL SIMULATION TRAINING IN STAGHORN NEPHROLITHIASIS MANAGEMENT]

Daily practice of a physician of any specialty is incomplete without an analysis of the data derived from the use of various imaging techniques. Over the past decade, there have been significant changes in the understanding of the clinical anatomy of the patient, which is largely the result of the introduction of modern computer technology in medicine.

Ureteroscopy for nephrolithiasis in transplanted kidneys

INTRODUCTION

While percutaneous nephrolithotomy (PCNL) is often the procedure of choice for renal and ureteral calculi in transplant kidneys, retrograde ureteroscopy (URS) is a less frequently applied but excellent option if stone burden is small. We retrospectively examined nine surgical cases performed in seven patients in what appears to be the largest single institutional series reported to date.

MATERIALS AND METHODS

Seven patients underwent nine retrograde URS between June of 2009 and September of 2013, by two endourologists. These cases were reviewed retrospectively.

RESULTS

Among the nine procedures, we were able to address the stone(s) endoscopically in seven. Among these procedures, laser lithotripsy was used in six cases, and basket stone extraction was applied in four procedures. Ureteral stents were placed following six procedures with ureteral access and treatment. Postoperative imaging revealed the patient to be stone free after five of the seven procedures with ureteral access and treatment. There were two postoperative urinary tract infections, and no major complications. Of the nine total procedures, six were outpatient, two were followed by observation stay < 24 hours, and one patient was admitted > 24 hours. Among the two failures, one underwent PCNL and the other had percutaneous nephrostomy (PNT) placed but expired from unrelated causes prior to the intended PCNL.

CONCLUSIONS

Retrograde URS with laser lithotripsy and/or basket extraction is a reasonable option for treating small renal transplant stones, with most patients in our series being discharged as outpatients, having complete stone clearance and avoiding PCNL.

Percutaneous stone removal: new approaches to access and imaging

Percutaneous renal access and removal of large renal calculi was first described nearly 40 years ago and has since become the gold standard in management of large and complex renal calculi. In this same time period, technological and medical advances have allowed this procedure to develop in improved efficacy and morbidity. The following review offers an update to new approaches to percutaneous renal access and imaging in the management of large and complex renal calculi.

Renal assessment in teenage patients with cystic fibrosis - preliminary report

BACKGROUND

Together with increasing life expectancy of patients with cystic fibrosis *CF*, there is a growing need to deal with unforeseen problems and complications. Among others renal dysfunction has become of great concern.

AIM

Evaluation of renal function in CF children.

MATERIAL AND METHODS

We performed cross-sectional study on a group of 11 teenage inpatients with CF. Physical examination, past medical history analysis, renal function measurements and analysis were conducted in all of them. Renal assessment included: serum cystatin C and creatinine levels, measured and estimated creatinine clearance, estimated cystatin C clearance, urine indicators of crystallization risk and renal ultrasonography.

RESULTS

One patient had elevated serum cystatin C level and diminished McIsaac equation. Renal ultrasound revealed non-congenital anomaly in 1 case - it was nephrolithiasis. All the individuals had elevated at least 1 urine indicator of crystallization risk.

CONCLUSION

There is a great need of good, standardized test of renal function in cystic fibrosis patients. The focus of research should turn towards finding a tool similar to faecal elastase, which is cheap, easy to perform, sensitive and specific, and can be used to confirm the diagnosis.

Osteoporosis and the risk of symptomatic nephrolithiasis: a population-based 5-year follow-up study in Taiwan

This study estimates the risk of symptomatic nephrolithiasis within 5 years of newly diagnosed osteoporosis in a Taiwan population. This cohort study consisted of patients with a diagnosis of osteoporosis between Jan. 2003 and Dec. 2005 (N = 1634). Four age- and gender- matched patients for every patient in the study cohort were selected using random sampling as the comparison cohort (N = 6536). All patients were tracked for 5 years from the date of cohort entry to identify whether they developed symptomatic nephrolithiasis. Cox proportional hazard regressions were performed to evaluate the 5-year nephrolithiasis-free survival rates. During the 5-year follow-up period, 60 osteoporosis patients (3.7%) and 165 non- osteoporosis patients (2.5%) developed symptomatic nephrolithiasis. The adjusted HR of symptomatic nephrolithiasis was 1.38 times greater risk for patients with osteoporosis than for the comparison cohort (95% confidence interval (CI) 1.03-1.86; P < .05). Osteoporosis is very likely to be an independent risk factor for subsequent diagnosis of symptomatic nephrolithiasis.

A lifetime of hypercalcemia and hypercalciuria, finally explained

CONTEXT

Hypercalcemia, hypercalciuria, and recurrent nephrolithiasis are all common clinical problems. This case report illustrates a newly described but possibly not uncommon cause of this presenting complex.

OBJECTIVE

We report on a patient studied for over 30 years, with the diagnosis finally made with modern biochemical and genetic tools.

DESIGN AND SETTING

This study consists of a case report and review of literature conducted in a University Referral Center.

PATIENT AND INTERVENTION

A single patient with hypercalcemia, hypercalciuria, and recurrent nephrolithiasis was treated with low-calcium diet, low vitamin D intake, prednisone, and ketoconazole.

MAIN OUTCOME MEASURE

We measured the patient's clinical and biochemical response to interventions above.

RESULTS

Calcium absorption measured by dual isotope absorptiometry was elevated at 37.4%. Serum levels of 24,25-dihydroxyvitamin D were very low, as measured in two laboratories (0.62 ng/mL [normal, 3.49 ± 1.57], and 0.18 mg/mL). Genetic analysis of CYP24A1 revealed homozygous mutation E143del previously described. The patient's serum calcium and renal function improved markedly on treatment with ketoconazole but not with prednisone.

CONCLUSIONS

Chronic hypercalcemia, hypercalciuria, and/or nephrolithiasis may be caused by mutations in CYP24A1 causing failure to metabolize 1,25-dihydroxyvitamin D.

Calcium oxalate crystallization index (COCI): an alternative method for distinguishing nephrolithiasis patients from healthy individuals

Urinary supersaturation triggers lithogenic crystal formation. We developed an alternative test, designated calcium oxalate crystallization index (COCI), to distinguish nephrolithiasis patients from healthy individuals based on their urinary crystallization capability. The effect of urine volume, oxalate, phosphate, citrate, potassium, and sodium on COCI values was investigated. COCI values were determined in 24-hr urine obtained from nephrolithiasis patients (n=72) and matched healthy controls (n=71). Increases in urine oxalate and phosphate and decreases in urine volume and citrate resulted in significantly increased COCI values. The urinary COCI in nephrolithiasis patients was significantly higher than that in healthy individuals. Two healthy subjects who had elevated COCI values were found to have asymptomatic kidney calculi. The receiver operating characteristic analysis showed an area under the curve of the urinary COCI test of 0.9499 (95%CI: 0.9131-0.9868) for distinguishing between nephrolithiasis and healthy subjects. At the cutoff of 165 mg oxalate equivalence/day, the urinary COCI test provided sensitivity, specificity, and accuracy amounts of 83.33%, 97.18%, and 90.21%, respectively. Urinary COCI values were primarily dependent on urine volume, oxalate, and phosphate. The test provided high sensitivity and specificity for clinically discriminating nephrolithiasis patients from healthy controls. It might be used to detect individuals with asymptomatic kidney calculi.

[Modern tactics of management of patients with bilateral staghorn nephrolithiasis]

A comparative analysis of the effectiveness of open and percutaneous operations in the treatment of bilateral staghorn nephrolithiasis (SN) was performed. Of the 38 patients with bilateral SN, stage operation (without discharge) was performed in 26 (68.5%) patients, and single-step operation--in 12 (31.5%) patients. For the 47 patients with bilateral SN, who underwent open surgery, the interventions were following: pelviolithotomy (64 operations), nephrolithotomy (21 operations), nephrectomy (9 operations). Surgery was performed in stages on each side, but unlike percutaneous operations, with discharge from the hospital. When using open surgery, only in 27 of the 47 patients complete discharge of kidney stones was achieved. A comparative analysis of single-step and stage surgery for bilateral SN revealed no significant difference in the duration of surgery and intraoperative blood loss (p > 0.1); endoscopic surgery compared with open surgery is characterized by significantly lower intraoperative blood loss and postoperative in-hospital stay (p < 0.001).

Extracorporal shock wave lithotripsy in the management of stones in children with oxalosis--still the first choice?

BACKGROUND

Primary hyperoxaluria (PH) is a recognised cause of nephrolithiasis. The aim of this study was to evaluate the success of extracorporal shock wave lithotripsy (ESWL) in treating nephrolithiasis in children with PH.

METHODS

This was a retrospective review of patient characteristics, treatments and outcomes of 36 children with oxalate stones due to PH.

RESULTS

A total of 52 stones were formed in 28 patients, of which 23 stones were treated with ESWL. Of these 23 stones, ten improved and 13 did not; nine were located in the upper pole, nine in the lower pole and four and one in the pelvic and ureteric areas, respectively. All pelvic and ureteric stones improved, while 66.7 % of upper pole stones and 89.9 % of lower pole stones did not; 20 % of PH type 1 stones improved compared to 47 % of PH type 2 stones. The mean pre- and post-eGFR in stone-improvers was 98.82 and 104.7 ml/min/1.73 m(2), respectively; in the non-improvers, these values were 100.75 and 95.68 ml/min/1.73 m(2), respectively. Mean pre-ESWL stone size in the improved and non-improved groups was 7.3 mm and 8.5 mm respectively.

CONCLUSIONS

Based on our results, ESWL is not the ideal method of stone therapy for patients with PH. ESWL was more effective in treating pelvic and ureteric stones, with upper pole stone response being better than lower pole response. PH2 patients were more than twice as likely to respond to ESWL treatment. Stone size and prior preventive treatment did not affect outcome. eGFR was not affected by ESWL.

Recent finding and new technologies in nephrolitiasis: a review of the recent literature

This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.