allopurinol and Urolithiasis

Hyperuricosuric calcium urolithiasis is a condition of mixed calcium oxalate stones characterized by hyperuricosuria either in isolation or in conjunction with other risk factors for calcium oxalate stones such as hypercalciuria, hyperoxaluria, and hypocitraturia. There are three proposed physicochemical models of pathogenesis where urate in its crystalline phase via heterogeneous nucleation, in its colloidal phase via removal of crystallization inhibitors, and in solution via precipitation crystallization, can all increase propensity to calcium oxalate precipitation. Regardless of the model, the phenomenologic observation of urate increasing calcium oxalate precipitation appears solid. Another supporting factor are retrospective data analysis and prospective trials showing uric acid lowering reduces stones events in hyperuricosuric calcium stone formers. Due to the heterogeneity of pathogenesis of calcium oxalate stones in the unselected stone-formers, association cannot be demonstrated between uric acid excretion rate and risk of kidney stone the general population. In calcium oxalate stoners with isolated hyperuricosuria or hyperuricosuria in combination with other calcium stone risks where treatment of these traditional risks fails to reduce stone formation, urate acid lowering should be cautiously attempted. More refinement of pathogenic models and prospective controlled trials in phenotypically defined subgroups of subjects with calcium oxalate urolithiasis will be informative.

Topics: Allopurinol; Calcium Oxalate; Chemical Phenomena; Gout Suppressants; Humans; Hypercalciuria; Risk Factors; Uric Acid; Urolithiasis

Adenine phosphoribosyltransferase (APRT) deficiency (OMIM #614723) is a rare autosomal recessive defect in the purine salvage pathway that causes excessive production of 2,8-dihydroxyadenine, leading to nephrolithiasis and chronic kidney disease (CKD). This case report describes the natural history of CKD in untreated APRT deficiency. We describe a novel APRT mutation (chr16:88877985 G / C; c.195 C>/G; p.His54Asp) presenting with CKD without nephrolithiasis. The patient initially required dialysis, but kidney function improved with allopurinol. We reviewed APRT deficiency reported in the literature to determine the loss of kidney function in individuals with untreated APRT deficiency and its relationship to nephrolithiasis. We identified 95 individuals in whom kidney function was assessed prior to treatment. There was a bimodal distribution of kidney failure. AKI occurred frequently in childhood due to obstructing nephrolithiasis or crystalline nephropathy and was usually reversible. CKD developed after age 20 in all patients irrespective of nephrolithiasis history, with 36/42 patients > 40 years of age having at least stage 3 CKD, and 24/42 having an eGFR > 10 mL/min/1.73m2 or being on dialysis. There were 13 adults without nephrolithiasis and 50 adults with nephrolithiasis. The mean age of end-stage renal diesease (ESRD) was 50.52 ± 13.9 for those without nephrolithiasis and 43.4 ± 15.8 years for those with nephrolithiasis (p = 0.24). APRT deficiency is associated with slowly progressive CKD that occurs independently of nephrolithiasis. Diagnosis should be considered in all individuals with chronic tubulointerstitial kidney disease, with or without the presence of nephrolithiasis. In our patient, allopurinol 300 mg/day resulted in improvement of kidney function.
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Topics: Adenine Phosphoribosyltransferase; Allopurinol; Antimetabolites; Glomerular Filtration Rate; Humans; Kidney Calculi; Male; Metabolism, Inborn Errors; Middle Aged; Nephritis, Interstitial; Renal Insufficiency, Chronic; Urolithiasis

The observed associations of hyperuricaemia with hypertension, cardiovascular disease and kidney disease are receiving increasing interest. The potential role of urate-lowering therapy in the management of these "non-gout diseases" has been raised, and in some countries it is already recommended. However, there is no consistent definition of hyperuricaemia or asymptomatic hyperuricaemia, much remains unknown about the causal role of urate in these "non-gout diseases" and there is currently a lack of evidence about the effects of urate lowering on disease progression. In addition, there is potential for serious adverse effects associated with urate-lowering therapies with recent evidence suggesting that asymptomatic hyperuricaemia may be an independent risk factor for the potentially fatal allopurinol hypersensitivity syndrome.. Pubmed was searched in January 2016 using the search term "asymptomatic hyperuricaemia".. Herein, we discuss the issues related to treating asymptomatic hyperuricaemia, which at present seems premature.

Topics: Allopurinol; Asymptomatic Diseases; Drug Eruptions; Drug Hypersensitivity; Febuxostat; Gout Suppressants; Humans; Hyperuricemia; Probenecid; Uricosuric Agents; Urolithiasis

The aim of this review was to provide current best evidence for evaluation, dietary, and medical management of patients with urolithiasis.. Literature addressing evaluation, dietary, and medical management of urolithiasis was searched. Papers were analyzed and rated according to level of evidence (LOE), whereupon a synthesis of the evidence was made. Grade of recommendation (GOR) was judged from individual clinical experience and knowledge of the evidence according to the Oxford Centre for Evidence-based Medicine.. It is obvious that different stone diseases influence the life of stone-forming individuals very differently, and that evaluation and medical management should be personalized according to risk of recurrence, severity of stone disease, presence of associated medical conditions, and patient's motivation. With regard to evaluation, dietary and medical management of patients with urolithiasis evidence from the literature suggest that selective metabolic evaluation may lead to rational dietary and medical management. Statements based on LOE and GOR are provided to guide clinical practice.. The provided evidence for evaluation of patients with urolithiasis aims at defining patients at high risk for recurrent/complicated stone disease. Based on this approach, evidence-based dietary and medical management regimes are suggested.

Topics: Allopurinol; Diet Therapy; Disease Management; Diuretics; Evidence-Based Medicine; Fluid Therapy; Gout Suppressants; Humans; Infrared Rays; Kidney Calculi; Potassium Citrate; Practice Guidelines as Topic; Sodium Chloride Symporter Inhibitors; Spectrum Analysis; Tomography, X-Ray Computed; Ultrasonography; Urinalysis; Urolithiasis; X-Ray Diffraction

Complete adenine phosphoribosyltransferase (APRT) deficiency is a rare inherited metabolic disorder that leads to the formation and hyperexcretion of 2,8-dihydroxyadenine (DHA) into urine. The low solubility of DHA results in precipitation of this compound and the formation of urinary crystals and stones. The disease can present as recurrent urolithiasis or nephropathy secondary to crystal precipitation into renal parenchyma (DHA nephropathy). The diagnostic tools available-including stone analysis, crystalluria, and APRT activity measurement-make the diagnosis easy to confirm when APRT deficiency is suspected. However, the disease can present at any age, and the variability of symptoms can present a diagnostic challenge to many physicians. The early recognition and treatment of APRT deficiency are of crucial importance for preventing irreversible loss of renal function, which still occurs in a non-negligible proportion of cases. This review summarizes the genetic and metabolic mechanisms underlying stone formation and renal disease, along with the diagnosis and management of APRT deficiency.

Topics: Adenine; Adenine Phosphoribosyltransferase; Allopurinol; Animals; Biomarkers; Disease Progression; Enzyme Inhibitors; Genetic Predisposition to Disease; Humans; Kidney Diseases; Metabolism, Inborn Errors; Phenotype; Predictive Value of Tests; Prognosis; Recurrence; Urolithiasis; Xanthine Dehydrogenase

Although significant progress has been made during the last 3 decades in the minimally invasive surgical management of stone disease, the medical prevention of urolithiasis still remains challenging as much less progress has been achieved during the same time period. The purpose of this article is to provide the practicing urologist with practical guidelines for the metabolic evaluation and management of the recurrent stone patient. The recommendations are based on the latest available information regarding the pathogenesis, medical treatment options, and decision-making rationale when managing these challenging patients.

Topics: Allopurinol; Biomarkers; Calcium; Humans; Magnesium; Monitoring, Physiologic; Oxalates; Potassium Citrate; Recurrence; Risk; Sodium Chloride Symporter Inhibitors; Urolithiasis

The modern view of treatment for various forms of nephrolithiasis reflects the main features of nephrolithiasis pathogenesis, but changes in metabolic condition, the presence of dysmetabolism, and the course of pathologic process are not taken into account. Considering that the disease is easier to prevent than to treat, it would be more appropriate to base preventive measures not only on the data from general clinical and biochemical examination, but also on the results of aggregatometry and complex chromato-mass-spectrometric examination allowing prediction of the development of the pathologic process.

Topics: Allopurinol; Diet, Protein-Restricted; Diuretics; Free Radical Scavengers; Humans; Potassium Citrate; Secondary Prevention; Treatment Outcome; Urolithiasis

In recent years stone disease has become more widespread in developed countries. At present the prevalence is 5.2 and 15% of men and 6% of women are affected. The increase is linked to changes in lifestyle, eating patterns and obesity which has become very common. The 'metabolic syndrome' includes all the diseases, e.g. hypertension, lipid imbalances, type 2 diabetes mellitus, gout and cardiovascular disease, which are concomitant in the majority of stone formers. Dietary patterns, besides leading to stone formation, also determine stone chemistry. With a diet that is rich in oxalates, calcium oxalate will constitute 75% of stones, struvite 10-20%, uric acid 5-6% and cystine 1%. As approximately 50% of patients with stones suffer recurrences, metabolic and/or pharmacological prophylaxis is recommended.

Topics: Allopurinol; Calcium Oxalate; Cystine; Diet; Dietary Supplements; Drinking; Humans; Life Style; Renal Agents; Secondary Prevention; Sodium Chloride Symporter Inhibitors; Uric Acid; Urinary Calculi; Urolithiasis

Urolithiasis is a worldwide problem and a risk factor for kidney injury. Oxidative stress-associated renal endothelial dysfunction secondary to urolithiasis could be a key pathogenic factor, similar to obesity and diabetes-related nephropathy. The aim of the present study was to characterize urolithiasis-related endothelial dysfunction in a hyperoxaluria rat model of renal lithiasis.. Endothelial dysfunction was assessed in preglomerular arteries isolated from control rats and in which 0.75% ethylene glycol was administered in drinking water. Renal interlobar arteries were mounted in microvascular myographs for functional studies; superoxide generation was measured by chemiluminescence and mRNA and protein expression by RT-PCR and immunofluorescence, respectively. Selective inhibitors were used to study the influence of the different ROS sources, xanthine oxidase, COX-2, Nox1, Nox2 and Nox4. Inflammatory vascular response was also studied by measuring the RNAm expression of NF-κB, MCP-1 and TNFα by RT-PCR.. Endothelium-dependent vasodilator responses were impaired in the preglomerular arteries of the hyperoxaluric group along with higher superoxide generation in the renal cortex and vascular inflammation developed by MCP-1 and promoted by NF-κB. The xanthine oxidase inhibitor allopurinol restored the endothelial relaxations and returned superoxide generation to basal values. Nox1 and Nox2 mRNA were up-regulated in arteries from the hyperoxaluric group, and Nox1 and Nox2 selective inhibitors also restored the impaired vasodilator responses and normalized NADPH oxidase-dependent higher superoxide values of renal cortex from the hyperoxaluric group.. The current data support that hyperoxaluria induces oxidative stress-mediated endothelial dysfunction and inflammatory response in renal preglomerular arteries which is promoted by the xanthine oxidase, Nox1 and Nox2 pathways.

Topics: Animals; Arteries; Hyperoxaluria; NF-kappa B; Oxidative Stress; Rats; Reactive Oxygen Species; RNA, Messenger; Superoxides; Urolithiasis; Xanthine Oxidase

Adenine phosphoribosyltransferase (APRT) deficiency is a rare, hereditary cause of kidney stones and chronic kidney disease (CKD) which is characterized by 2,8-dihydroxyadenine renal parenchymal crystal deposition. The aim of this study was to examine outcomes of kidney transplantation in APRT deficiency patients.. Included were 13 patients in the APRT Deficiency Registry of the Rare Kidney Stone Consortium, 2 from Westmead Hospital in Sydney, Australia, and 2 from Necker Hospital in Paris, France. The CKD-EPI and CKiD equations were used to calculate glomerular filtration rate estimates. Allograft survival was analyzed employing the Kaplan-Meier method. The Wilcoxon-Mann-Whitney test was used to compare alllograft outcomes according to xanthine oxidoreductase (XOR) inhibitor treatment status at transplantation.. Seventeen patients (9 females) received 22 kidney transplants. Age at first transplantation was 47.2 (14.9-67.0) years. Ten patients received XOR inhibitor therapy pretransplant (11 allografts), while 8 patients did not receive such treatment before transplantation (11 allografts). Two-year allograft survival was 91% and 55% in the 2 groups, respectively (P = 0.16). The median (range) estimated glomerular filtration rate at 2 years posttransplant was 61.3 (24.0-90.0) mL/min/1.73 m when XOR inhibitor therapy was initiated before transplantation, and 16.2 (10.0-39.0) mL/min/1.73 m (P = 0.009) when such treatment was not administered pretransplant.. Kidney allograft outcomes are good in APRT deficiency patients beginning XOR inhibitor therapy pretransplant. Delay in such treatment is a major cause of premature graft loss in these patients. Increased awareness among clinicians is imperative, promoting early diagnosis of APRT deficiency and pharmacotherapy initiation before kidney transplantation.

Topics: Adenine Phosphoribosyltransferase; Adolescent; Adult; Aged; Allopurinol; Enzyme Inhibitors; Europe; Febuxostat; Female; Graft Survival; Humans; India; Kidney Failure, Chronic; Kidney Transplantation; Male; Metabolism, Inborn Errors; Middle Aged; New South Wales; Retrospective Studies; Risk Factors; Time Factors; Treatment Outcome; United States; Urolithiasis; Xanthine Oxidase; Young Adult

Adenine phosphoribosyl transferase (APRT) deficiency is a rare genetic form of kidney stones and/or kidney failure characterized by intratubular precipitation of 2,8 dihydroxyadenine crystals. Early diagnosis and prompt management can completely reverse the kidney injury.. 44 year old Indian male, renal transplant recipient got admitted with acute graft dysfunction. Graft biopsy showed light brown refractile intratubular crystals with surrounding giant cell reaction, consistent with APRT deficiency. Patient improved after receiving allopurinol and hydration.. APRT forms a reversible cause of crystalline nephropathy. High index of suspicion is required for the correct diagnosis as timely diagnosis has therapeutic implications.

Topics: Adenine; Adenine Phosphoribosyltransferase; Adult; Allopurinol; Antimetabolites; Biopsy; Crystallization; Humans; Hydrotherapy; Kidney Transplantation; Male; Metabolism, Inborn Errors; Primary Graft Dysfunction; Urolithiasis

Adenine phosphoribosyltransferase (APRT) deficiency is a hereditary purine metabolism disorder that causes kidney stones and chronic kidney disease (CKD). The purpose of this study was to examine the course of APRT deficiency in patients who presented in childhood.. The disease course of 21 (35%) patients in the APRT Deficiency Registry of the Rare Kidney Stone Consortium, who presented with manifestations of APRT deficiency and/or were diagnosed with the disorder before the age of 18 years, was studied. The effect of pharmacotherapy on renal manifestations and outcomes was thoroughly assessed.. Fourteen children were placed on allopurinol, 100 (25-200) mg/day, at the age of 2.6 (0.6-16.5) years. Six of these patients had experienced kidney stone events and three had developed acute kidney injury (AKI) prior to allopurinol treatment. During 18.9 (1.7-31.5) years of pharmacotherapy, stones occurred in two patients and AKI in three. Six adult patients started allopurinol treatment, 200 (100-300) mg/day, at age 29.8 (20.5-42.4) years. Five of these patients had experienced 28 stone episodes and AKI had occurred in two. Stone recurrence occurred in four patients and AKI in two during 11.2 (4.2-19.6) years of allopurinol therapy. Lack of adherence and insufficient dosing contributed to stone recurrence and AKI during pharmacotherapy. At latest follow-up, estimated glomerular filtration rate (eGFR) was 114 (70-163) and 62 (10-103) mL/min/1.73 m. Timely diagnosis and treatment of APRT deficiency decreases renal complications and preserves kidney function.

Topics: Acute Kidney Injury; Adenine; Adenine Phosphoribosyltransferase; Adolescent; Adult; Allopurinol; Child; Child, Preschool; Disease Progression; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Infant; Kidney; Kidney Calculi; Male; Metabolism, Inborn Errors; Recurrence; Registries; Renal Insufficiency, Chronic; Urolithiasis; Xanthine Dehydrogenase; Young Adult

Adenine phosphoribosyltransferase (APRT) deficiency is a rare, but significant, cause of kidney stones and progressive chronic kidney disease. The optimal treatment has not been established. The purpose of this pilot study was to compare the effect of the xanthine oxidoreductase inhibitors allopurinol and febuxostat on urinary 2,8-dihydroxyadenine (DHA) excretion in APRT deficiency patients.. Patients listed in the APRT Deficiency Registry of the Rare Kidney Stone Consortium, currently receiving allopurinol therapy, were invited to participate. The trial endpoint was the 24-h urinary DHA excretion following treatment with allopurinol (400mg/day) and febuxostat (80mg/day). Urinary DHA was measured using a novel ultra-performance liquid chromatography - electrospray tandem mass spectrometry assay.. Eight of the 10 patients invited completed the study. The median (range) 24-h urinary DHA excretion was 116 (75-289) mg at baseline, and 45 (13-112) mg after 14days of allopurinol therapy (P=0.036). At the end of the febuxostat treatment period, 4 patients had urinary DHA below detectable limits (<20ng/mL) compared with none of the participants following allopurinol treatment (P=0.036). The other 4 participants had a median 24-h urinary DHA excretion of 13.2 (10.0-13.4) mg at the completion of febuxostat therapy (P=0.036).. Urinary DHA excretion in APRT deficiency patients decreased with conventional doses of both allopurinol and febuxostat. Febuxostat was, however, significantly more efficacious than allopurinol in reducing DHA excretion in the prescribed doses. This finding, which may translate into improved outcomes of patients with APRT deficiency, should be confirmed in a larger sample.

Topics: Adenine; Adenine Phosphoribosyltransferase; Adult; Aged; Allopurinol; Cross-Over Studies; Enzyme Inhibitors; Febuxostat; Female; Humans; Iceland; Kidney Calculi; Male; Metabolism, Inborn Errors; Middle Aged; Pilot Projects; Registries; Treatment Outcome; Urolithiasis

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive disorder which leads to accumulation of poorly soluble 2,8-dihydroxyadenine in kidneys resulting in nephrolithiasis as well as chronic kidney disease from crystal nephropathy. This report describes a 55-year-old previously fit man who presented with shortness of breath and the investigative pathway that eventually led to a diagnosis of APRT deficiency. Early diagnosis has aided in timely institution of allopurinol, thereby improving his renal function and possibility of weaning off renal replacement therapy. Genetic testing has enabled early identification of other family members at risk and prevention of renal failure by commencing xanthine oxidoreductase (XOR) inhibitors. The issues surrounding kidney donation by a member of this family are also discussed. This case represents the importance of awareness and recognition of the signs and symptoms of this rare condition, complications of which can be easily prevented by early institution of XOR inhibitor therapy.

Topics: Adenine Phosphoribosyltransferase; Allopurinol; Early Diagnosis; Enzyme Inhibitors; Humans; Male; Metabolism, Inborn Errors; Middle Aged; Pedigree; Urolithiasis

Topics: Adenine Phosphoribosyltransferase; Allopurinol; Child, Preschool; Dose-Response Relationship, Drug; Drug Administration Schedule; Enzyme Inhibitors; Female; Humans; Metabolism, Inborn Errors; Urolithiasis

Adenine phosphoribosyltransferase deficiency is a rare autosomal recessive disorder of uric acid metabolism that leads to formation and excretion of 2,8-dihydroxyadenine into urine. The low solubility of 2,8-dihydroxyadenine results in precipitation and formation of urinary crystals and renal stones. Patients with this disorder usually have recurrent nephrolithiasis and can develop nephropathy secondary to crystal precipitation in the renal parenchyma. The disease is most often underdiagnosed and can recur in renal transplant, causing graft failure. Lack of specific clinical manifestations, chemical and radiologic features identical to those shown with uric acid stones, and lack of awareness among clinicians are among the causes for the underdiagnoses of this treatable disease. Allopurinol, a xanthine dehydrogenase inhibitor, is the mainstay of treatment, supported by high fluid intake and dietary modifications. The possibility of adenine phosphoribosyl transferase deficiency should be considered in all cases of urolithiasis in children, patients with recurrent urolithiasis, and patients with urolithiasis associated with renal failure of unknown cause, including patients with end-stage renal disease and renal transplant recipients. Here, we report a case of a 41-year-old female patient who had a late diagnosis of 2,8-dihydroxyadenine nephropathy-induced end-stage renal disease, made on the native nephrectomy that accompanied the renal transplant, and who had a timely intervention that prevented recurrence in the graft.

Topics: Adenine; Adenine Phosphoribosyltransferase; Adult; Allopurinol; Biomarkers; Biopsy; Enzyme Inhibitors; Female; Humans; Kidney Failure, Chronic; Kidney Transplantation; Metabolism, Inborn Errors; Treatment Outcome; Urolithiasis; Xanthine Dehydrogenase

Topics: Allopurinol; Animals; Antimetabolites; Dog Diseases; Dogs; Male; Urolithiasis; Xanthine

The object of this study was to evaluate the effect of uric acid lowering therapy in reducing the new development of comorbidities and the frequency of acute attacks in gout patients. We retrospectively reviewed patients who were diagnosed to have gout with at least 3 yr of follow up. They were divided into 2 groups; 53 patients with mean serum uric acid level (sUA)<6 mg/dL and 147 patients with mean sUA≥6 mg/dL. Comorbidities of gout such as hypertension (HTN), type II diabetes mellitus (DM), chronic kidney disease, cardiovascular disease (CVD) and urolithiasis were compared in each group at baseline and at last follow-up visit. Frequency of acute gout attacks were also compared between the groups. During the mean follow up period of 7.6 yr, the yearly rate of acute attack and the new development of HTN, DM, CVD and urolithiasis was lower in the adequately treated group compared to the inadequately treated group. Tight control of uric acid decreases the incidence of acute gout attacks and comorbidities of gout such as HTN, DM, CVD and urolithiasis.

Topics: Adult; Allopurinol; Antimetabolites; Benzbromarone; Cardiovascular Diseases; Comorbidity; Diabetes Mellitus, Type 2; Enzyme Inhibitors; Febuxostat; Female; Gout; Gout Suppressants; Humans; Hypertension; Male; Middle Aged; Renal Insufficiency, Chronic; Retrospective Studies; Thiazoles; Uric Acid; Uricosuric Agents; Urolithiasis

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive disorder characterized by 2,8-dihydroxyadenine (2,8-DHA) crystalluria that can cause nephrolithiasis and chronic kidney disease. The aim of our study was to assess the clinical presentation, diagnosis, and outcome of APRT deficiency in a large pediatric cohort. All pediatric cases of APRT deficiency confirmed at the same French reference laboratories between 1978 and 2010 were retrospectively reviewed. Twenty-one patients from 18 families were identified. The median age at diagnosis was 3 years. Diagnosis was made after one or more episodes of nephrolithiasis (17 patients), after urinary tract infection (1 patient), and by family screening (3 patients). The diagnosis was based on stone analysis and microscopic examination of urine and/or enzymatic determination of APRT on red blood cells. All children had null APRT enzyme activity in erythrocytes. APRT gene sequencing was performed on 18 patients, revealing six homozygous and 12 compound heterozygous mutations. At diagnosis, half of the patients had decreased kidney function, and two children presented with acute renal failure. Allopurinol treatment was given to all patients at a median dose of 9 mg/kg/day. After a median follow-up of 5 years, all patients showed stabilization or improvement of kidney function, normal growth and development, and six patients had recurrence of nephrolithiasis. Based on these results, we conclude that an excellent outcome can be achieved in children with APRT deficiency who receive the proper treatment.

Topics: Adenine Phosphoribosyltransferase; Adolescent; Allopurinol; Antimetabolites; Child; Child, Preschool; Female; Humans; Infant; Male; Metabolism, Inborn Errors; Retrospective Studies; Urolithiasis; Young Adult

To find factors associated with the development of renal colic during uricosuric therapy.. We performed a prospective cohort followup study of patients with gout and no previous history of kidney stones who had been treated with uricosurics. Clearance of creatinine and urate, 24-hour urinary uric acid (UA), undissociated urinary UA concentration, 24-hour undissociated urinary UA, and pH and urine sediment were obtained. Cox proportional hazards regression analysis was used to identify variables associated with renal colic as the outcome. The rate of renal colic was compared with that of control patients receiving allopurinol who had no previous history of renal stones.. We analyzed a 784 patient-year exposure from 216 patients: 206 with renal underexcretion of UA and 10 with normal excretion. There were 21 clinical events. Two variables showed increased risk hazard for developing lithiasis: clearance of UA at baseline and undissociated urinary UA concentration during followup. When only patients with underexcretion of UA were included in the analysis, undissociated urinary UA during followup remained the only statistically significant variable. Patients who showed an undissociated UA concentration < 20 mg/dl did not show an increase in the rate of lithiasis or events compared with patients receiving allopurinol.. Clearance of UA at baseline may be useful for selecting patients suitable for uricosuric treatment. The estimation of the concentration of undissociated urinary UA is useful for evaluating the risk of lithiasis during followup.

Topics: Allopurinol; Benzbromarone; Cohort Studies; Creatinine; Follow-Up Studies; Gout; Humans; Hyperuricemia; Middle Aged; Proportional Hazards Models; Prospective Studies; Renal Colic; Risk Factors; Time Factors; Uric Acid; Uricosuric Agents; Urolithiasis

Acute renal failure (ARF) is one of the complications of urolithiasis, but the role of medical treatment to relieve urinary obstruction in children with ARF is uncertain. We report on infants with acute obstructive uric acid lithiasis. We describe presentation features as well as diagnosis methods and medical treatment in five infants who were admitted to our institution with ARF due to uric acid lithiasis. The medical treatments for all patients were fluid liberalization, urine alkalinization, and oral allopurinol. Two children underwent urinary diversion. Within 8 h, urine output improved in all patients, and the stones passed spontaneously. All obstructed kidneys were relieved with medical treatment, and no renal sequel remained. So this series has showed a role of medical therapy in acute obstructive uric acid lithiasis.

Topics: Acute Kidney Injury; Allopurinol; Antimetabolites; Female; Fluid Therapy; Humans; Infant; Male; Prospective Studies; Treatment Outcome; Urinary Diversion; Urolithiasis

Lesch-Nyhan syndrome is a very rare X-linked recessive disorder caused by mutation in the gene encoding enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). A complete deficiency of HPRT leads to severe purine overproduction and to uric acid renal lithiasis as a consequence. This may be effectively prevented by administration of allopurinol; however, its overdosage may result in xanthinuria and xanthine urolithiasis. We report on a 9-year-old boy with Lesch-Nyhan syndrome who developed acute renal failure due to bilateral staghorn xanthine urolithiasis resulting from long-term treatment with excessive doses of allopurinol. To the best of our knowledge, the presented case is the first one in the literature.

Topics: Acute Kidney Injury; Allopurinol; Child; Humans; Lesch-Nyhan Syndrome; Male; Urolithiasis; Xanthine Oxidase; Xanthines