Cystinuria Complicated by Anuria From Bilateral Obstructing Stones Requiring Bilateral Mini Percutaneous Nephrolithotomy in a 22-Month-Old.

Pediatric nephrolithiasis is increasing in incidence and presents differently compared to adults. We report a case of nephrolithiasis in a pediatric patient, presenting with complaints of emesis, anuria, hematuria, and abdominal distension, leading to a diagnosis of bilateral obstructing cystine stones requiring bilateral percutaneous nephrolithotomy. Pediatric patients with anuria should be evaluated for bilateral nephrolithiasis as an etiology. Calculous anuria requires prompt recognition of the pathologic process and relief of the obstruction with close follow-up and supportive care until definitive stone management. Bilateral percutaneous nephrolithotomy can provide definitive surgical intervention without significant morbidity.

Hydration for Adult Patients with Nephrolithiasis: Specificities and Current Recommendations.

Nephrolithiasis affects around 10% of the population and is frequently associated with impaired dietary factors. The first one is insufficient fluid intake inducing reduced urine volume, urine supersaturation, and subsequently urinary lithiasis. Kidneys regulate 24 h urine volume, which, under physiological conditions, approximately reflects daily fluid intake. The aim of this study is to synthesize and highlight the role of hydration in the treatment of nephrolithiasis. Increasing fluid intake has a preventive effect on the risk of developing a first kidney stone (primary prevention) and also decreases the risk of stone recurrence (secondary prevention). Current guidelines recommend increasing fluid intake to at least at 2.5 L/day to prevent stone formation, and even to 3.5-4 L in some severe forms of nephrolithiasis (primary or enteric hyperoxaluria or cystinuria). Fluid intake must also be balanced between day and night, to avoid urinary supersaturation during the night. Patients should be informed and supported in this difficult process of increasing urine dilution, with practical ways and daily routines to increase their fluid intake. The liquid of choice is water, which should be chosen depending on its composition (such as calcium, bicarbonate, or magnesium content). Finally, some additional advice has to be given to avoid certain beverages such as those containing fructose or phosphoric acid, which are susceptible to increase the risk of nephrolithiasis.

Why is childhood urolithiasis increasing? Etiology, diagnosis and management: a single-center experience.

BACKGROUND: Globally, urolithiasis is becoming more and more common among children. We aimed to determine the etiology, and the diagnostic and therapeutic approaches in patients with urolithiasis. METHODS: This was a retrospective study which included all patients (aged 1 month-18 years) admitted to the pediatric nephrology clinic in Elazig Fethi Sekin City Hospital with urolithiasis between November 2019 and 2021. Only patients whose diagnosis of urolithiasis was confirmed by urinary ultrasonography were included in the study, while patients with chronic diseases (neurological diseases such as epilepsy, cerebral palsy, chronic bowel diseases, etc.) predisposing to kidney stone formation were not. Demographic characteristics, serum and urine biochemical parameters, urine metabolic and kidney stone metabolic and chemical analyses, urinary tract ultrasonography findings and treatment modalities were collected. RESULTS: One hundred ninety-seven patients (91 female and 106 male) were included in the study. Hypervitaminosis D was detected in 4 (2%) patients, suppressed parathyroid hormone in 12 (6%) and hypercalcemia in 27 (14%) patients. Metabolic screening showed hypercalciuria in 69 (35%) patients, hypocitraturia in 39 (20%), hyperoxaluria in 15 (8%) and cystinuria in 6 (3%) patients. Eighty three (42%) patients had a positive family history for kidney stones. One hundred eighteen (60%) patients received potassium citrate treatment, 71 (36%) were given hydration and diet recommendations without medical treatment, 6 (3%) received tiopronin treatment, and 2 (1%) patients were treated surgically. CONCLUSIONS: Our study suggests that Vitamin D supplementation at doses higher than 400 IU/day may be a risk factor for kidney stones in children. We observed that mothers tend not to give water to infants who are breastfed or formula-fed in the first year of life. K-citrate treatment can be a good option for prevention and dissolution of stones by alkalinization.

Entering into 2.0 cystinuric management with a medical digital tool to monitor urine pH: a prospective, randomized study.

BACKGROUND AND OBJECTIVES: Individuals with cystinuria can experiment recurrent lithiasis events due to the relative insolubility of cystine at physiological urine pH, resulting in renal function decline. The Lit-Control® pH Meter is a medical device that accurately allows urine pH self-monitoring. The main objective of this study was to compare the usability of the Lit-Control® pH Meter with the reactive strips for self-monitoring of urinary pH at home by patients with cystinuria, and their overall satisfaction with each tool. PATIENTS AND METHODS: We included 28 patients (9 females and 19 males, age 19-76 years), who were randomly assigned to monitor their urine pH with reactive strips (n = 17) or the Lit-Control® pH-meter (n = 11). RESULTS: After six months of use, the satisfaction with the two methods was similarly high, but the patients rated (0-10 scale) the pH meter better in terms of ease of learning (mean ±â€¯SD, 8.11 ±â€¯0.60 vs. 7.06 ±â€¯1.18; P = 0.038), ease to prepare (8.22 ±â€¯0.67 vs. 7.25 ±â€¯1.18; P = 0.034), and ease of use (8.22 ±â€¯0.67 vs. 7.25 ±â€¯1.39; P = 0.062). Overall, patients did not reach the alkalinization goals (pH between 7.0 and 8.0). CONCLUSIONS: The Lit-Control® pH Meter demonstrated to be an easy-to-use device that can facilitate urinary pH control by cystinuric patients. A prospective study is warranted to assess the correlation between urine pH monitoring, a treat to target approach, and the recurrence of cystine stones.

Case-based review of dietary management of cystinuria.

PURPOSE: The currently recommended treatment strategy for cystine stone formers is based on a progressive approach that starts with the most conservative measures. In patients with cystinuria, increased patient compliance with dietary management and medical treatment is associated with fewer stone interventions. In this case-based review, the dietary management of cystine stone former was reviewed under the guidance of evidence-based medicine. METHODS: The dietary management of the 13-year-old cystinuria patient, who underwent 18 endourological stone interventions, was reviewed in the light of evidence-based medicine. A literature search was performed in Pubmed, MEDLINE, Embase, and Cochrane Library databases according to PRISMA guidelines published from 1993 to September 2022. A total of 304 articles were included in this paper. RESULTS: In managing patients with cystinuria, hyperhydration, and alkalinization of the urine with medical treatment, the rational use of cystine-binding drugs by taking into account individual situations has come to the fore. A limited study has argued that a vegetarian diet is effective as the alkaline load from fruits and vegetables can reduce the amount of alkalizing substances required to achieve urinary alkalinization above pH 7.5, making it particularly suitable for the dietary treatment of cystine stone disease. CONCLUSION: Life-long follow-up with dietary modification, hyperhydration, and personalized medical therapy (alkalinization and cystine-binding drugs) are critical in preventing chronic kidney disease and kidney failure in cystinuria.

Pediatric urolithiasis: what can pediatricians expect from radiologists?

The incidence of urolithiasis in children has increased over the two last decades. Urolithiasis formation results from urine oversaturation following insufficient water intake, urinary obstruction (notably in cases of congenital uropathies), excess production of an insoluble compound, or imbalance between crystallization promoters and inhibitors. Whereas most urolithiases in adults occur secondary to environmental factors, in children, secondary causes are far more frequent, and 15% are related to genetic causes, most often monogenic. This is especially true in recurrent forms, with early and rapid progression and bilateral stones, and in cases of familial history or consanguinity. Because of differing clinical management, one should rule out cystinuria, primary hyperoxaluria and renal tubular acidosis, among other causes of urolithiasis. As such, a complete biochemical evaluation must be performed in all cases of pediatric urolithiasis, even in cases of an underlying uropathy. Ultrasound examination is the first-line modality for imaging pediatric urolithiasis, allowing both diagnosis (urolithiasis and its complications) and follow-up. US examination should also explore clues to an underlying cause of urolithiasis. This review is focused on the role of imaging in the management and etiological assessment of pediatric urolithiasis. Radiologists play an important role in pediatric urolithiasis, facilitating diagnosis, follow-up and surgical management. A trio of clinicians (pediatric nephrologist, pediatric surgeon, pediatric radiologist) is thus necessary in the care of these pediatric patients.

Cistinuria como causa de litiasis urinaria / Cystinuria as a cause of urolithiasis

La cistinuria es una enfermedad genética que provoca un defecto de reabsorción de cistina, causando como manifestación principal litiasis urinarias que pueden llegar a ser de gran tamaño. Es importante tratarla desde temprana edad porque puede comportar importantes comorbilidades. (AU)

Cystinuria is a genetic disease that causes impaired cystine reabsorption. Its main manifestation is urolithiasis, in some cases producing very large stones. It is important to treat it from an early age because it can lead to important comorbidities. (AU)

Disrupting Crystal Growth through Molecular Recognition: Designer Therapies for Kidney Stone Prevention.

Aberrant crystallization within the human body can lead to several disease states or adverse outcomes, yet much remains to be understood about the critical stages leading to these events, which can include crystal nucleation and growth, crystal aggregation, and the adhesion of crystals to cells. Kidney stones, which are aggregates of single crystals with physiological origins, are particularly illustrative of pathological crystallization, with 10% of the U.S. population experiencing at least one stone occurrence in their lifetimes. The human record of kidney stones is more than 2000 years old, as noted by Hippocrates in his renowned oath and much later by Robert Hooke in his treatise Micrographia. William Hyde Wollaston, who was a physician, chemist, physicist, and crystallographer, was fascinated with stones, leading him to discover an unusual stone that he described in 1810 as cystic oxide, later corrected to cystine. Despite this long history, however, a fundamental understanding of the stages of stone formation and the rational design of therapies for stone prevention have remained elusive.This Account reviews discoveries and advances from our laboratories that have unraveled the complex crystal growth mechanisms of l-cystine, which forms l-cystine kidney stones in at least 20 000 individuals in the U.S. alone. Although l-cystine stones affect fewer individuals than common calcium oxalate stones, they are usually larger, recur more frequently, and are more likely to cause chronic kidney disease. Real-time in situ atomic force microscopy (AFM) reveals that the crystal growth of hexagonal l-cystine is characterized by a complex mechanism in which six interlaced anisotropic spirals grow synchronously, emanating from a single screw dislocation to generate a micromorphology with the appearance of stacked hexagonal islands. In contrast, proximal heterochiral dislocations produce features that appear to be spirals but actually are closed loops, akin to a Frank-Read source. These unusual and aesthetic growth patterns can be explained by the coincidence of the dislocation Burgers vector and the crystallographic 61 screw axis. Inhibiting l-cystine crystal growth is key to preventing stone formation. Decades of studies of "tailor-made additives", which are imposter molecules that closely resemble the solute and bind to crystal faces through molecular recognition, have demonstrated their effects on crystal properties such as morphology and polymorphism. The ability to visualize crystal growth in real time by AFM enables quantitative measurements of step velocities and, by extension, the effect of prospective inhibitors on growth rates, which can then be used to deduce inhibition mechanisms. Investigations with a wide range of prospective inhibitors revealed the importance of precise molecular recognition for binding l-cystine imposters to crystal sites, which results in step pinning and the inhibition of step advancement as well as the growth of bulk crystals. Moreover, select inhibitors of crystal growth, measured in vitro, reduce or eliminate stone formation in knockout mouse models of cystinuria, promising a new pathway to l-cystine stone prevention. These observations have wide-ranging implications for the design of therapies based on tailor-made additives for diseases associated with aberrant crystallization, from disease-related stones to "xenostones" that form in vivo because of the crystallization of low-solubility therapeutic agents such as antiretroviral agents.

Cystinuria poorly responding to treatment - the risk of chronic kidney disease.

Cystinuria is the genetic condition for the increased excretion of cystine in the urine. Patients mainly suffer from afflictions related to the presence and passage of kidney stones. The currently available treatment methods include conservative treatment based on increased fluid intake, appropriate diet, medications and urological procedures. The causal treatment has not yet been invented. A CASE REPORT: A patient case was described whose first symptomatic kidney stones appeared after the second year of life. Urinary cystine excretion was significantly increased - 25,431 µmol/1g creatinine (norm: 167-333 µmol/1g creatinine), which was also shown, but lower, in both parents of the patient. Despite the early initiation of therapy including low sodium diet, abundant hydration, alkalization, captopril and compliance with stringent restrictions, the level of urinary cystine excretion was still not within the normal range. There have been many modifications to the therapy and dose increases of drugs, but without visible results. The patient underwent several urological procedures, including: ESWL (Extracorporeal shock wave lithotripsy), URSL (Ureteroscopic lithotripsy), PCNL (Percutaneous nephrolithotomy) and open surgery to remove cystine deposits that were still produced in the kidneys. In addition, for many years the disease was complicated by recurrent urinary tract infections, underweight and lesions like epithelial metaplasia in the bladder. Renal parameters were repeatedly examined. Elevated results such as: serum creatinine 0.9 mg/dl, cystatin C concentration 1.10 mg/l, albumin-creatinine index 0.197, creatinine clearance 50.7 ml/min /1.73 m2 and eGFR 73 ml/min/1.73 m2 allowed for the diagnosis of chronic kidney disease before the age of 18. After many years of conservative treatment, only the introduction of thiopronine, still little known in Poland, reduced the level of cystine excreted in the urine. The inclusion of the drug reduced the tendency to produce kidney stones, which allowed to inhibit the progression of renal failure. CONCLUSIONS: Despite many years of research and modern drugs, cystinuria is still a disease with which patients are associated for the rest of their lives. The ongoing research, along with attempts to understand the genetic and epigenetic mechanisms responsible for the emergence of mutations in the main genes causing the disease and the course of the disease, gives hope for finding a method of causal treatment for cystinuria.

The Impact of Diet on Urinary Risk Factors for Cystine Stone Formation.

Despite the importance of dietary management of cystinuria, data on the contribution of diet to urinary risk factors for cystine stone formation are limited. Studies on the physiological effects of diet on urinary cystine and cysteine excretion are lacking. Accordingly, 10 healthy men received three standardized diets for a period of five days each and collected daily 24 h urine. The Western-type diet (WD; 95 g/day protein) corresponded to usual dietary habits, whereas the mixed diet (MD; 65 g/day protein) and lacto-ovo-vegetarian diet (VD; 65 g/day protein) were calculated according to dietary reference intakes. With intake of the VD, urinary cystine and cysteine excretion decreased by 22 and 15%, respectively, compared to the WD, although the differences were not statistically significant. Urine pH was significantly highest on the VD. Regression analysis showed that urinary phosphate was significantly associated with cystine excretion, while urinary sulfate was a predictor of cysteine excretion. Neither urinary cystine nor cysteine excretion was affected by dietary sodium intake. A lacto-ovo-vegetarian diet is particularly suitable for the dietary treatment of cystinuria, since the additional alkali load may reduce the amount of required alkalizing agents.

An Update on Evaluation and Management in Cystinuria.

Cystinuria is the most common cause of inherited stone disease and is caused by the failure of absorption of filtered dibasic amino acids including cystine in the proximal tubules. It is associated with a very high recurrence rate in affected patients, with the potential for significant morbidity in such patients due to the need for repeated surgical interventions. A multimodal and multispecialty approach in a dedicated centre is the key to improving treatment outcomes and patient adherence to the treatment. This article reviews the latest knowledge on the clinical and diagnostic features and summarises key developments to aid clinicians in diagnosis and management options, together with future directions for the care of these patients.

Metabolic and Clinical Characteristics of Children with Urolithiasis from Southern India.

OBJECTIVE: To study the etiological profile and patterns of clinical presentations of urolithiasis (UL) in children. METHODS: This observational study included patients <18 y with UL, who were referred to the pediatric nephrology clinic. Clinical features, family history, consanguinity and estimated glomerular filtration rate (eGFR) at presentation and follow-up were recorded. The children were evaluated using relevant blood and urine investigations. RESULTS: A total of 72 children with UL were evaluated for the study. The etiology of UL (n = 72) included hyperoxaluria (n = 25; 34.7%), idiopathic hypercalciuria (n = 21; 29.2%), idiopathic hyperuricosuria (n = 3; 4.2%), cystinuria (n = 3; 4.2%), urate transporter defect (n = 2; 2.8%) and mixed stones (predominant component calcium oxalate) (n = 9; 12.5%). No etiology was detected in 4 cases (5.5%). Common presenting complaints included flank pain (n = 41; 56.7%), hematuria (n = 29; 40.3%), urinary tract infection (UTI) (n = 29; 40.3%) and vomiting (n = 11; 15.3%). The median age of presentation was 60 (36, 96) mo. Family history and consanguinity were present in 30 cases (41.7%) and 28 cases (38.9%) respectively. Stone analysis was done in 20 cases, of which 9 cases were mixed stones (predominant calcium oxalate) and 6 were calcium oxalate stones. CONCLUSIONS: Among children with urolithiasis, hyperoxaluria, idiopathic hypercalciuria, idiopathic hyperuricosuria, and cystinuria were the predominant identifiable entities, together accounting for 72% of cases; and renal colic, hematuria and UTI were the commonest clinical complaints.

Assessment of health-related quality of life in patients with cystinuria on tiopronin therapy.

Cystinuria comprises less than 1% of kidney stones and is associated with impaired health-related quality of life (HRQOL). Limited evidence is available regarding HRQOL of patients with cystinuria treated with tiopronin (Thiola®). The objective of this study was to assess the HRQOL of patients with or without tiopronin treatment. For this cross-sectional survey, patients on tiopronin treatment were recruited through the "Thiola® Total Care Hub," a specialty pharmacy used to dispense tiopronin, and compared with patients not taking tiopronin (non-tiopronin group) who were identified from the Cystinuria Contact Registry at New York University School of Medicine. Consented patients responded to a survey that included questions about their experiences with kidney stones, the Wisconsin stone quality of life (WISQOL) (disease-specific) questionnaire, and the short form-36 version 2 (SF-36v2) (generic) HRQOL questionnaire. Statistical analyses included independent-sample t tests, one-way analysis of variance (ANOVA), and correlations. The survey was completed by 312 patients: 267 in the tiopronin group (144 male, 123 female; mean 49 years) and 45 in the non-tiopronin group (10 male, 35 female; mean 48 years). Both groups utilized pain medications similarly (24% overall). Patients on tiopronin had a significantly better HRQOL than patients not on tiopronin for all WISQOL domains (p < 0.001) and all but the physical functioning SF-36v2 domain (p < 0.001), where both groups approached the US normative mean, when controlling for the last stone event. Compared with patients in the non-tiopronin group, patients taking tiopronin reported better HRQOL on both the WISQOL and SF-36v2.

Hypertension and renal impairment in patients with cystinuria: findings from a specialist cystinuria centre.

Higher blood pressures (mean systolic difference 16.8 mmHg) when compared to matched individuals are already reported in patients with calcium urolithiasis. We present the prevalence of hypertension and renal impairment in patients with cystinuria from our specialist single centre. We analysed our prospective database of adult patients with cystinuria who attend our cystinuria service. This included details of the medical and operative management of their disease. Descriptive statistics were used to analyse and present the data. 120 patients were included with a median age of 40 (19-76) years, 66 were male (55%) and 54 were female (45%). 54/120 patients (45%) were taking medications to prevent stone formation. 78% (94/120) patients reported having undergone one or more stone-related procedure. 59% (55/94) of these having required at least one PCNL or open procedure during their lifetime. Prevalence of hypertension was 50.8% (61/120), and double in males compared to females (62.1% vs. 37.0%, P = 0.0063). Mean baseline creatinine was 88.2 (49-153) µmol/l and eGFR was 77.6 (32-127) ml/min/1.73 m2. When categorized by CKD stage, only 24.6% (27% vs. 21%, M vs. F) patients had normal renal function (being an eGFR > 89 ml/min/1.73 m2). 57.6% patients were CKD stage 2 and 17.8% CKD stage 3. Females had a slightly greater incidence of renal impairment. All patients who have previously undergone a nephrectomy (n = 10) or have a poorly functioning kidney (n = 19) have renal impairment (CKD stage 2 or 3). Incidence of hypertension in patients with cystinuria is 51%, with a male preponderance. Only 25% of patients with cystinuria have normal renal function. This highlights the long-term cardiovascular and renal risks that the metabolic effects of cystinuria pose, in addition to the challenges of managing recurrent urolithiasis in a young population.

Cystinuria: genetic aspects, mouse models, and a new approach to therapy.

Cystinuria, a genetic disorder of cystine transport, is characterized by excessive excretion of cystine in the urine and recurrent cystine stones in the kidneys and, to a lesser extent, in the bladder. Males generally are more severely affected than females. The disorder may lead to chronic kidney disease in many patients. The cystine transporter (b0,+) is a heterodimer consisting of the rBAT (encoded by SLC3A1) and b0,+AT (encoded by SLC7A9) subunits joined by a disulfide bridge. The molecular basis of cystinuria is known in great detail, and this information is now being used to define genotype-phenotype correlations. Current treatments for cystinuria include increased fluid intake to increase cystine solubility and the administration of thiol drugs for more severe cases. These drugs, however, have poor patient compliance due to adverse effects. Thus, there is a need to reduce or eliminate the risks associated with therapy for cystinuria. Four mouse models for cystinuria have been described and these models provide a resource for evaluating the safety and efficacy of new therapies for cystinuria. We are evaluating a new approach for the treatment of cystine stones based on the inhibition of cystine crystal growth by cystine analogs. Our ongoing studies indicate that cystine diamides are effective in preventing cystine stone formation in the Slc3a1 knockout mouse model for cystinuria. In addition to crystal growth, crystal aggregation is required for stone formation. Male and female mice with cystinuria have comparable levels of crystalluria, but very few female mice form stones. The identification of factors that inhibit cystine crystal aggregation in female mice may provide insight into the gender difference in disease severity in patients with cystinuria.

Renal stones in two children with two rare etiologies.

The incidence of urolithiasis in children has shown an increase in recent years which may be attributed to changing dietary patterns, sedentary lifestyles, and obesity. Among the various etiologies for renal stones in children, two rare entities worth mentioning are cystinuria and 2, 8-dihydroxyadenine (DHA) urolithiasis. Cystinuria is an inherited cause of nephrolithiasis which occurs due to impaired cystine reabsorption in the renal proximal tubule. 2, 8-DHA urolithiasis is an inherited autosomal recessive disease resulting in urinary stone disease secondary to deficiency of adenine phosphoribosyltransferase (APRT) activity. We describe two children who presented to our clinic with these two rare causes of stones.

The impact of surgical intervention on renal function in cystinuria / O impacto da intervenção cirúrgica sobre a função renal na cistinúria

ABSTRACT Introduction: Cystinuria is an autosomal recessive disorder due to intestinal and renal transport defects in cystine and dibasic amino acids, which result in recurrent urolithiasis and surgical interventions. This study aimed to assess the impact of surgical interventions on renal function by analyzing estimated glomerular filtration rates. Methods: Thirteen pediatric patients with cystinuria, who were followed-up in a single tertiary institution between 2004 and 2016, were included in the study. Medical records were reviewed to collect data on clinical presentation of patients, urine parameters, stone formation, medical treatment, surgical intervention, stone recurrence after surgical procedure, stone analysis, ultrasonography, 99m-technetium dimercaptosuccinic acid (99mTc-DMSA) radionuclide imaging results, and follow-up time. Creatinine clearances estimated by modified Schwartz (eGFR) formula before and after surgery were used to assess renal function and compared statistically. Results: Nine patients (69.2%) had renal scarring which were detected with 99mTc-DMSA radionuclide imaging. In ten patients (76.9%), open surgical intervention for stones were needed during follow-up. Significant difference was not detected between eGFR before and after surgical intervention (mean 92 versus 106, p = 0.36). Nine of the patients (69.2%) were stone free in the last ultrasonographic examination. Relapses of stone after surgery were seen in 66.6% of patients who underwent surgical intervention. Conclusions: Surgical interventions for urinary stones are commonly required in patients with cystinuria. Renal scarring is a prevalent finding in cystinuric patients. Surgical interventions have no negative impact on eGFR in patients with cystinuria according to the present study.

RESUMO Introdução: A cistinúria é um distúrbio autossômico recessivo causado por defeitos de transporte intestinal e renal da cistina e aminoácidos dibásicos que resultam em urolitíase recorrente e necessidade de intervenção cirúrgica. O presente estudo teve por objetivo avaliar o impacto das intervenções cirúrgicas sobre a função renal por meio da análise da taxa de filtração glomerular estimada. Métodos: Treze pacientes pediátricos com cistinúria acompanhados em uma instituição terciária entre 2004 e 2016 foram incluídos no estudo. Os prontuários médicos foram analisados e utilizados como fonte de dados sobre a apresentação clínica dos pacientes, parâmetros urinários, formação de cálculos, tratamento clínico, intervenção cirúrgica, recidiva de cálculos após procedimento cirúrgico, análise de cálculos, ultrassonografia, resultados de imagens com ácido dimercaptossuccínico marcado com tecnécio metaestável (99mTc-DMSA) e tempo de seguimento. A depuração de creatinina estimada pela fórmula modificada de Schwartz (TFGe) antes e após a cirurgia foi utilizada para avaliar e comparar estatisticamente os níveis de função renal. Resultados: Nove pacientes (69,2%) apresentaram cicatrizes renais detectadas por exame de imagem com 99mTc-DMSA. Dez pacientes (76,9%) necessitaram intervenção cirúrgica aberta por cálculo renal durante o seguimento. Não foram detectadas diferenças significativas entre os valores de TFGe anteriores e posteriores à intervenção cirúrgica (média de 92 vs. 106, p = 0,36). Nove pacientes (69,2%) não apresentaram cálculos no último exame ultrassonográfico. Recidivas de cálculos renais após cirurgia foram observadas em 66,6% dos pacientes submetidos a cirurgia. Conclusões: Intervenções cirúrgicas relativas a cálculos renais são frequentemente necessárias em pacientes com cistinúria. Cicatrizes renais são um achado prevalente em pacientes com cistinúria. De acordo com o presente estudo, cirurgia não afeta negativamente a TFGe de pacientes com cistinúria.

Reporte de un caso de Cistinuria: Uso de herramientas de diagnóstico a nivel nacional / Report of a case of cystinuria: Use of diagnostic tools at national level

La cistinuria es una enfermedad genética que se engloba dentro de alteraciones congénitas del transporte de aminoácidos con formación de cálculos en las vías urinarias, si bien es poco frecuente se caracteriza por su elevada recurrencia. En este trabajo presentamos el caso de una paciente de 34 años, con antecedentes de haber perdido un riñón por episodios anteriores de litiasis y con múltiples recidivas que es diagnosticada mediante la detección de cistina por espectroscopía infrarroja como componente único de 96 fragmentos de cálculos removidos mediante nefrolitotomía percutánea. La paciente fue evaluada laboratorialmente mediante el perfil metabólico y la cristaluria. Las indicaciones de tratamiento específicas incluyeron la administración de agentes alcalinizantes, régimen nutricional, y entrenamiento para control de pH urinario. Es importante señalar la agresividad de la litiasis de cistina con las consecuencias que puede tener la calidad de vida del paciente, y por tanto la importancia de contar con capacidades instaladas a nivel país para el diagnóstico y seguimiento de litiasis genéticas como la causada por la cistinuria(AU)

Cystinuria is a genetic disease that is included among congenital defects of renal amino acids transport that causes urinary stone formation. Although it is rare, it is characterized by its high recurrence. We present the case of a 34-year-old patient that lost one of her kidney because of recurrent episodes of lithiasis, and that was diagnosed by the detection of cystine with infrared spectroscopy as the sole component of 96 stone fragments removed by percutaneous nephrolithotomy. The patient was evaluated by metabolic profile and crystalluria. The specific treatment indications included the administration of alkalinizing agents, nutritional regimen, and training for personal measurement of urinary pH. This case highlights the aggressiveness of cystine stones with the consequences that may have on the quality of the patient life, and therefore the importance of having installed proper diagnostic capacities at national level to detect and monitor treatment efficacy in genetic lithiasis such as cystinuria(AU)

Conversion from Cystine to Noncystine Stones: Incidence and Associated Factors.

PURPOSE: Patients with cystinuria are often treated with medical alkalization and shock wave lithotripsy, although each treatment is hypothesized to increase the risk of calcium phosphate stones. We performed a multicenter retrospective review to evaluate whether stones of another composition develop in patients with cystinuria and with what frequency. MATERIALS AND METHODS: We retrospectively reviewed the records of a multi-institutional cohort of patients with cystinuria. We assessed medications, stone analyses, 24-hour urinalyses and types of procedures. We compared patients who formed only cystine stones vs those with noncystine stones. RESULTS: We identified 125 patients from a total of 5 institutions who were followed a mean of 5.2 years (range 0 to 26). Stones with noncystine components were submitted by 37 patients (29.6%). Potassium citrate medication was not associated with a noncystine composition (p = 0.1877). Regarding surgical management 18 patients (13%) underwent at least 1 shock wave lithotripsy session (range 0 to 9) and 79 (63%) underwent percutaneous nephrolithotomy at least once (range 0 to 10). When stratified based on pure cystine vs converted stones, the average total number of shock wave lithotripsy and percutaneous nephrolithotomy procedures was higher in the group with cystine and subsequent noncystine stone compositions (0.94 vs 0.10, p <0.0001, and 1.7 vs 1.5, p = 0.0053, respectively). On logistic regression male gender (OR 3.1, p = 0.0280) and the number of shock wave lithotripsy sessions (OR 3.0, p = 0.0170) were associated with an increased likelihood of the development of stones with a noncystine composition. CONCLUSIONS: Stones with noncystine components develop in more than 25% of patients with cystinuria, underscoring the importance of continued stone analysis. In this study prior shock wave lithotripsy was associated with conversion to a noncystine stone composition while urinary alkalization therapy was not associated.